key: cord- -skhoro authors: oboh, mary aigbiremo; omoleke, semeeh akinwale; imafidon, christian eseigbe; ajibola, olumide; oriero, eniyou cheryll; amambua-ngwa, alfred title: beyond sars-cov- : lessons that african governments can apply in preparation for possible future epidemics date: - - journal: j prev med public health doi: . /jpmph. . sha: doc_id: cord_uid: skhoro severe acute respiratory syndrome coronavirus (sars-cov- ) has placed unprecedented pressure on healthcare systems, even in advanced economies. while the number of cases of sars-cov- in africa compared to other continents has so far been low, there are concerns about under-reporting, inadequate diagnostic tools, and insufficient treatment facilities. moreover, proactiveness on the part of african governments has been under scrutiny. for instance, issues have emerged regarding the responsiveness of african countries in closing international borders to limit trans-continental transmission of the virus. overdependence on imported products and outsourced services could have contributed to african governments’ hesitation to shut down international air and seaports. in this era of emerging and re-emerging pathogens, we recommend that african nations should consider self-sufficiency in the health sector as an urgent priority, as this will not be the last outbreak to occur. in addition to the regional disease surveillance systems enhancement fund (us$ million) provided by the world bank for strengthening health systems and disease surveillance, each country should further establish an epidemic emergency fund for epidemic preparedness and response. we also recommend that epidemic surveillance units should create a secure database of previous and ongoing pandemics in terms of aetiology, spread, and treatment, as well as financial management records. strategic collection and analysis of data should also be a central focus of these units to facilitate studies of disease trends and to estimate the scale of requirements in preparation and response to any future pandemic or epidemic. severe acute respiratory syndrome coronavirus (sars-cov- ), which was initially detected in wuhan, china in december , has gradually snowballed into a worldwide pandemic [ ] . it has placed unprecedented pressure on healthcare systems, pissn - eissn even in advanced economies [ ] . as of april , , there were over . million confirmed cases globally and recorded deaths [ ] . although the numbers of cases and deaths reported in africa remain comparatively low [ ] , this might be an underrepresentation of the disease burden due to the challenges of insufficient diagnostic testing kits and centres relative to the teeming high population of the continent. these inadequacies are major causes of concern for disease control efforts, given the potential for gradual but steady geometric inter-community and intra-community spread because the virus has a high reproductive number and a short serial interval [ ] . given the various epidemic events that have previously oc-curred in africa, from ebola virus disease (evd) [ ] to yellow fever, cholera, measles and lassa fever [ ] , it would almost be safe to assume that african governments have prepared proactive measures against possible future epidemics. however, such proactive measures in africa towards pandemic situations still seem to be far-fetched, as demonstrated by the approach towards the novel sars-cov- pandemic. considering the high virulence of the pathogen and the rapid spread of the disease, there was a significant time lapse between the first confirmed case outside of china (thailand, on january , ) and confirmation of the first sars-cov- case in africa (specifically, in egypt on february , ) compared to other continents [ ] . the question then arises that, beyond the current containment efforts by various african countries, could they have done better to prevent the spread of this viral infection into and within the continent based on previous experiences with other emerging and re-emerging pathogens? with the great risk of trans-continental transmission of pathogenic agents due to the high emigrational tendency of africans to western countries and vice versa (for greener pastures and/ or tourism), and dependency on imported products into the continent from countries in the global north, african leaders should have been more proactive in closing and/or reducing travel into the continent. a measure could have been applied to restrict travel even from countries with fewer than confirmed sars-cov- cases given that the virus is highly transmissible, with a high reproductive number [ ] . for example, nigeria's travel ban was implemented on march , ( weeks after the first imported case) for countries with more than cases at that time, despite convincing evidence regarding potential importation from other countries not listed, while a total airport ban came a week later (march , ) [ ] . some proactive countries such as djibouti suspended all international flights before recording any cases of sars-cov- in the country. the authors are aware of the international health regulations, which frown at undue impositions of travel and trade restrictions due to a public health emergency of international concern. however, in the context of overwhelming evidence of an absent or inadequate national capacity to respond or cope with the epidemic, it is inevitable for countries to promptly wield international and local travel restrictions to slow down and reduce the peak of the epidemic. african countries, with their heavy reliance on their counterparts in the global north for medical supplies, should have purchased medical consumables, such as testing kits and per-sonal protective equipment, and should have initiated training of personnel and surveillance officers who will be needed in the event of an epidemic. it is worrisome, however, to observe different ministries of health from african countries scavenging for these supplies when they are already burdened with hundreds of active cases. apparently, borders and air spaces were left open, yet with little or no preparations made for the potential cases that were allowed into the countries. generally, the continent of africa suffers from deficiencies in human capacity and infrastructure, especially in medical and health research [ ] . hence, without the availability of the necessary consumables, trained laboratory scientists, clinicians, nurses, and other health workers for effective case management and systematic contact tracing, there will still be a huge gap in the management of coronavirus disease (cov-id- ) pandemic in africa, with potentially disastrous consequences. evidence suggests that many african countries had a relatively weak epidemic preparedness and response capacity before the current outbreak [ ] . these weaknesses have improved modestly, but not sufficiently to combat the covid- pandemic. despite the challenges mentioned above and the aftermath of the west african ebola crisis, the world bank supported the launching of the regional disease surveillance systems enhancement (redisse) with us$ million to strengthen the health systems and disease surveillance in west and central african countries. similarly, funds have been provided to support the african centers for disease prevention and control to build human capacity, provide guidelines, and coordinate epidemic prevention and response activities across the african continent. furthermore, other lessons learnt and builtup from the recent evd outbreak prompted the implementation of improved airport surveillance, temperature screening at points of entry, and training and scaling up of molecular diagnostic capacity for sars-cov- [ ] . a few countries, such as nigeria, south africa, algeria, ghana, and egypt, initiated some of these measures somewhat earlier, but were not decisive about the implementation of travel restrictions or bans, thereby allowing the importation of sars-cov- virus into africa. some key lessons from the current outbreak of sars-cov- include the dire need to improve hospital facilities (e.g., intensive care unit upgrading and expansion through the procurement of ventilators and other life-saving equipment, upgrading emergency medical facilities, and improved diagnostic capacity), retention of highly skilled human resources, epidemic preparedness, sustained surveillance, and baseline health demographic data for chronic infectious and non-communicable diseases that could serve as potential risk factors for aggravated outcomes of new and emerging diseases. african leaders cannot afford to be complacent in responding to such issues given their previous encounters with evd, and now sars-cov- . these experiences should serve as a wake-up call for african countries to prepare for possible future outbreaks. in conclusion, africa and the world at large will never remain the same after the covid- pandemic. therefore, the heads of states on the african continent should adopt preventive and precautionary measures rather than reactionary measures. in addition to the redisse fund (us$ million) created by the world bank for strengthening health systems and disease surveillance, each country should further map out an epidemic emergency fund that will be used to address situations such as this in the future. further, we recommend that epidemic surveillance units, under the ministry of health, should be strengthened in all african countries. these units should be given the responsibility to create a secure database of previous and ongoing pandemics in terms of aetiology, spread, and treatment, as well as financial management records. strategic collection and analysis of data should also be a central focus of these unit to facilitate the analysis of disease trends and to estimate the scale of all necessary resources in preparation and response to any future pandemic or epidemic. this paper is a perspective, so it did not need ethical approval. coronavirus disease and influenza - africa centre for disease control and prevention. covid- scientific and public health policy update insight into novel coronavirus -an updated interim review and lessons from sars-cov and mers-cov ebola virus disease (evd): an unprecedented major outbreak in west africa infectious disease outbreaks in the african region: overview of events reported to the world health organization coronavirus disease (covid- ) situation report - update on clarification of flight restriction into nigeria due to covid- pandemic preparedness and vulnerability of african countries against importations of covid- : a modelling study quagmire of epidemic disease outbreaks reporting in nigeria world health organization regional office for africa. who ramps up preparedness for novel coronavirus in the african region none. the authors have no conflicts of interest associated with the material presented in this paper. none. key: cord- -rgqwm vb authors: olarte-castillo, ximena a.; hofer, heribert; goller, katja v.; martella, vito; moehlman, patricia d.; east, marion l. title: divergent sapovirus strains and infection prevalence in wild carnivores in the serengeti ecosystem: a long-term study date: - - journal: plos one doi: . /journal.pone. sha: doc_id: cord_uid: rgqwm vb the genus sapovirus, in the family caliciviridae, includes enteric viruses of humans and domestic animals. information on sapovirus infection of wildlife is limited and is currently lacking for any free-ranging wildlife species in africa. by screening a large number of predominantly fecal samples (n = ) obtained from five carnivore species in the serengeti ecosystem, east africa, sapovirus rna was detected in the spotted hyena (crocuta crocuta, family hyaenidae), african lion (panthera leo, family felidae), and bat-eared fox (otocyon megalotis, family canidae), but not in golden or silver-backed jackals (canis aureus and c. mesomelas, respectively, family canidae). a phylogenetic analysis based on partial rna-dependent rna polymerase (rdrp) gene sequences placed the sapovirus strains from african carnivores in a monophyletic group. within this monophyletic group, sapovirus strains from spotted hyenas formed one independent sub-group, and those from bat-eared fox and african lion a second sub-group. the percentage nucleotide similarity between sapoviruses from african carnivores and those from other species was low (< . %). long-term monitoring of sapovirus in a population of individually known spotted hyenas from to revealed: i) a relatively high overall infection prevalence ( . %); ii) the circulation of several genetically diverse variants; iii) large fluctuations in infection prevalence across years, indicative of outbreaks; iv) no significant difference in the likelihood of infection between animals in different age categories. the likelihood of sapovirus infection decreased with increasing hyena group size, suggesting an encounter reduction effect, but was independent of socially mediated ano-genital contact, or the extent of the area over which an individual roamed. environmental contamination might be an important route for fecal-oral transmission of sapovirus, for example when spotted hyenas sniff virus infected feces or ingest water contaminated with virus infected feces. if so, individuals with a limited range may be less likely to encounter virus infected feces than those with an extensive range. in the serengeti np, adult and subadult hyenas (i.e. those ! months of age) not only range throughout the approximately km of their clan's territory, but also undertake long distance foraging trips (of approximately km distance round-trip) from their clan territory [ , ] . the ranges of cubs (< months of age) are by comparison extremely limited, being restricted to the communal den area within the clan territory [ ] . if the extent of an animal's range determines its chance of encountering virus infected feces, then all else being equal, cubs should be less often infected with sapovirus than older animals. finally, sapovirus transmission might depend on basic population parameters such as population density, principally represented by clan (group) size. if the chance of transmission increases with animal density, then individuals living in larger clans should be more likely to be infected than those in smaller clans. however, if an encounter reduction effect operates [ , ] , then we expect the chance of susceptible individuals encountering an infected animal to decline with clan size. in humans, sapovirus infection is currently thought to provide immunological protection, at least to antigenically homologous sapoviruses, although specific immunological responses are still unknown [ ] . currently nothing is known about the immunological responses of spotted hyenas to sapovirus infection, or the length of immunological protection following sapovirus infection. even so, if sapovirus infection induces long-term immunity against reinfection regardless of strain-type, we would expect cubs (i.e. naïve animals) to be more prone to infection than adults, as is the case for coronavirus infection in this species [ ] . however, if sapovirus infection provides only short-term immunity, we would expect re-infections among animals of all ages. if immune responses are strain-specific, re-infection would also be expected in animals of all ages, following the appearance of a divergent strain. this study aims to advance knowledge of sapovirus infection in wild carnivore communities in africa. we report the identification of sapoviruses in wild carnivores in africa and investigate the genetic diversity of strains infecting sympatric carnivore species in the serengeti ecosystem. we assess temporal changes in sapovirus infection in a large population of individually known spotted hyenas during a period spanning more than a decade and investigate whether sapovirus infection provides long-term immunity against future infection. furthermore, we test three mechanisms likely to affect the fecal-oral spread of sapovirus infection in spotted hyenas. this study was conducted in the serengeti np, from february to march . fresh fecal samples (n = ) were collected shortly after deposition from individually known spotted hyenas including samples from adults (females n = , males n = ), samples from subadults (females n = , males n = ) and samples from cubs (females n = , males n = ) from three large clans (denoted in fig as i, p, and m). fecal samples were also collected from other carnivores in the serengeti np (african lion, panthera leo, n = ; bat-eared fox, otocyon megalotis, n = ; silver-backed jackal, canis mesomelas, n = samples; golden jackal, canis aureus, n = ). following collection, feces were thoroughly mixed and divided in aliquots. tissue samples ( intestine, liver, lung, lymph node, spleen, blood, muscle, saliva) were also collected opportunistically from dead spotted hyenas which were mostly killed by lions or when hit by motor vehicles [ ] and hence were not necessarily members of study clans, and from two other carnivore species (bat-eared fox: intestines; silver-backed jackal: intestine, liver, lung). both fecal and tissue samples were stored and transported frozen at - °c, or were preserved in rnalater (sigma-aldrich inc., st. louis, mo, usa), stored initially at - °c, and finally stored at - °c until analyses [ , ] . currently, porcine enteric calicivirus (pec) cowden strain [ , ] is the only known sapovirus that can be cultured. hence, viral detection and initial characterization involves mostly molecular methods based on sequence data of the well-conserved rna-dependent rna polymerase (rdrp) and the variable structural vp genes [ , ] . in this study, sapovirus rna was detected by targeting the highly conserved rdrp gene. total rna was extracted from μl of % (wt/vol) fecal suspension in depc-treated water using the qiaamp minelute virus spin kit (qiagen, hilden, germany), according to manufacturer's instructions. sapovirus rna was detected with the broadly reactive primer pair p and p [ ] targeting highly conserved motifs in the rdrp protein of caliciviruses. based on the sequences initially generated, nested primers were designed, cali f ( '-cag tga cag cca cat cct tg- ') and cali r ( '-agc act gca gca gca aag ta- '), targeting the rdrp gene. rt-pcr was performed using superscript tm iii one-step rt-pcr system with platinum taq dna polymerase (invitrogen, karlsruhe, germany) following the user manual's instructions in a total reaction volume of μl. amplicons of the expected size were purified using the qiagen pcr purification kit (qiagen, hilden, germany). in order to avoid rnases, all surfaces were cleansed with rnase away (molecular bioproducts, san diego, ca, usa). the purified products were sequenced bidirectional using the big dye terminator cycle sequencing kit . (applied biosystems [abi], darmstadt, germany) following the manufacturer's instructions. a genetic analyzer (abi) was used for the sequencing. subsequently, sequences were assembled in geneious v . . (biomatters ltd, auckland, new zealand) or bioedit . . . [ ] . samples that could not be sequenced were considered positive when bands of the expected size were present with both primer pairs. for these samples the rt-pcrs were run in duplicate to ensure that the results were reliable. to obtain a longer segment of the rdrp gene, the primer r ( '-rcc ctc cat ytc aaa cac ta- ') was used together with the primer calir .. genbank accession numbers for sequences identified by this study are designated kt -kt . these accession number are included in our phylogenetic tree (fig ) , together with the host species, the year in which the variant was collected and for spotted hyenas also clan membership, denoted as i,m,p if know or z if not known. all partial rdrp genes sequences ( nucleotides, amino-acids) presented the characteristic caliciviral glpsg motif. one sample from a spotted hyena in was sequenced for a longer fragment of the rdrp gene ( nucleotides, amino-acids, accession number kt ) which presented both the glpsg motif and the ygdd motif. sapovirus sequences obtained in this study for the partial rdrp gene together with others retrieved from genbank were aligned using the muscle algorithm [ ] in geneious v . . (biomatters ltd, auckland, new zealand). at least one reference sequence of each of the five genogroups of sapovirus (gi-gv) was included in the analysis (gi, n = , accession numbers ay , ay , dq , u , u , gii, n = , ay , ay , ay , giii, n = , fj , af , fj , giv, n = , dq , gv, n = , ay ). additional sapovirus sequences from domestic dog (jn , jn ), california sea lion (jn ), mink (ay ) and bats (jn , jn , jn ) were included. viruses from other genera in the caliciviridae family known to infect carnivores were also included, such as feline calicivirus (af - ) and canine calicivirus (af , ab ) from the vesivirus genus, and a norovirus reported from a captive african lion (genus norovirus, ef ). average nucleotide and amino-acid similarities were calculated using discovery studio visualizer . (accelrys software inc, san diego, usa). phylogenetic relationships were reconstructed using maximum likelihood (ml) and bayesian markov chain monte carlo (mcmc) phylogenetic inferences. the ml analysis was performed in paup à . b [ ] using , bootstrap replicates to estimate the statistical support of the branches. the bayesian analysis was carried out using mrbayes version . [ , ] . the mcmc search was set to , , iterations, with trees sampled every , th iteration. the nucleotide substitution model used in the ml analysis was obtained using modeltest . [ ] and for the bayesian analysis using mrmodeltest . [ ] . for both cases the akaike information criterion (aic) was used to select the best-fitting model. to determine factors influencing the likelihood of sapovirus infection and changes in long-term infection prevalence we screened feces from individually recognized spotted hyenas in three study clans (i,m,p). age was estimated when individuals were first sighted as cubs, to an accuracy of ± days [ ] using pelage characteristics, whether their ears were flattened or upright, and their coordination during locomotion [ , ] . we classified animals as cubs when less than months of age, as subadults when between and less than months of age, and as adults when ! months of age [ ] . sex was determined by the dimorphic glans morphology of the erect phallus [ ] . total clan size comprised all adults, subadults and cubs of both sexes. access to food resources in clan territories is determined by social status: all immigrant males are socially subordinate to female clan members and their offspring at food resources in the clan territory [ ] . we determined the rank of adults in separate female and breeding male linear dominance hierarchies using the outcome of submissive responses in dyadic interactions within each sex, as detailed in [ , , ] . to compare individual ranks across clans of different sizes, we used standardized ranks. we calculated the standardized rank of each individual within its clan on the date it was sampled using the method described by [ ] . this method assigns standardized ranks between - (held by the animal with the lowest rank) and + (held by the animal with the highest rank) [ , ] . adult females with standardized ranks higher or equal to the median standardized rank of were classified as holding high social status, those with standardized ranks below as low social status [ ] . cubs and subadults were assigned the social status of their mother [ ] . all immigrant males held a social status below adult clan females [ ] . if sapovirus infection depends on intra-specific contact rates, we would expect the dynamics of social interactions within each clan to determine exposure to pathogens. for this purpose we constructed an index of social (ano-genital during greeting ceremonies) contact rates in spotted hyenas as follows. we combined social status and sex in that high ranking females and their offspring were given a high score (for contact rate), low ranking females and their offspring were given a medium score, and immigrant and reproductively active natal males were given a low score. in order to assess whether the range of an animal, the size of the area over which an individual typically roams, determines the chance of exposure to pathogens, we classified adults and subadults of both sexes with an extensive geographical foraging range as 'roaming' , because they range both within their clan territory (~ - km ) and undertake long distance foraging trips outside the clan territory [ , ] . cubs were classified as 'den-bound' , i.e., with a small range restricted to the vicinity of the communal den inside the clan territory. for the purpose of considering the effect of basic population parameters such as population density on incidence of infection we used total clan size on the date each animal was sampled. to investigate whether sapovirus infection provided immunity against re-infections we genetically screened feces from individually known spotted hyenas from which fecal samples were obtained on at least two different dates. of these, individuals were screened on two different dates, individuals on three different dates and individuals on four different dates. using these screening results we calculated the average interval duration between two successive sampling dates. we used nonparametric models, including the mann-whitney u-test and the kruskal-wallis test, to compare medians [ ] and the kaplan-meier survivorship and the logrank test in survival analyses to compare the survivorship curves of intervals between different combinations of incidences of infection [ ] . to investigate differences in the prevalence of sapovirus in the spotted hyena population studied between and we first tested for differences in the prevalence of infection across years, using a log-likelihood ratio-test. for this test we only considered years with a sample size of at least individuals, thus years , and were excluded where sample sizes were , and , respectively. we also checked for possible differences between age categories, using the same statistical test. these analyses were run in systat version (systat software inc., richmond, va, usa). we then ran models to assess which of three possible mechanisms influenced the likelihood of sapovirus infection in our study population. for this purpose we used binary logistic regression models [ ] , with predictor variables contact rate, lifetime range and clan size, and ran these as mixed models with animal identity as a random variable to account for the fact that some individuals contributed more than one tissue or fecal sample to the data set. if a genetic screening result was available for more than one organ or fecal sample for an individual on the same sampling date, only one result was included in the dataset for the prevalence models; if we obtained both a positive and negative result from an animal on the same day, the positive result was selected. this applied to individuals where we had two fecal samples from the same day, and to individuals from which altogether tissue samples were examined. we included data from all individuals sampled during the years which could either be classified as outbreak or non-outbreak years (see results). models were run with the glmer function of package lme version . - in in r (r development core team, v. . . ). we used log-likelihood ratio tests and information criteria (aic and schwartz's [bic s ] and raftery's bayesian information criterion [bic r ]) to check whether the final model was superior to an intercept-only or a reduced model. models were considered similar if differences in aic were less than . and preferable if the difference exceeded . [ ] ; similar if differences in bic r were less than . , a positive degree of preference if values of bic r varied between . and . and a strong degree of preference if values of bic r differed by more than (a. raftery in [ ] , p ). as the evaluation of our models with all information criteria produced similar conclusions, we report only aic values. the significance of each predictor variable was assessed in the following way. we calculated the marginal contribution of each parameter to the full model by subtracting from the full model the log-likelihood ratio of a second model with each variable removed and testing the difference against a chi-square distribution with the appropriate degrees of freedoms (see discussions in [ , ] ). in order to illustrate the effect of clan size on the chance of infection, we proceeded as follows. we calculated "covariate adjusted estimates" of the logits for each record over the observed range of values by adjusting them to the median of the remaining covariates (contact rate, lifetime range) of their log-odds (logit) for being infected ( [ ] , p ), and then converted the resulting estimates into probabilities using the logistic equation. this permitted us to show the effect of clan size on the likelihood of infection whilst controlling for the covariates contact rate and lifetime range at their middle values. the significance threshold for all tests was fixed at % and all tests were two-tailed. the data used for the statistical analyses is contained in s table. ethics statement the study was approved by the tanzanian commission of science and technology (cost-ech) and the tanzania wildlife research institute (tawiri). permission to work in the serengeti national park was granted by the tanzanian national parks authority (tanapa). the work was also approved by the internal ethics committee of the leibniz institute for zoo and wildlife research (izw), approval no. - - . screening targeting the conserved rdrp gene revealed sapovirus rna in feces from spotted hyena ( . %, / samples), african lion ( . %, / samples) and bat-eared fox ( . %, / samples). no sapovirus rna was found in fecal samples from golden ( / ) or silverbacked jackals ( / ). sapovirus rna was found in tissue samples collected opportunistically from dead spotted hyenas (spleen, / samples, liver / samples, lymph node / samples), but not in intestine ( / samples) or lung samples ( / samples). animals with positive spleen samples were negative for sapovirus rna in their other available tissues ( lymph nodes; liver; lung). a total of partial rdrp gene sequences ( from spotted hyenas, from african lions and from bat-eared foxes) were obtained and used for the phylogenetic analysis, together with publically available sequence data from representatives of all sapovirus genogroups, divergent unclassified sapoviruses, and other genera in the caliciviridae family, including norovirus and vesivirus. the sapovirus strains from wild carnivore species in the serengeti ecosystem were placed together in one independent monophyletic cluster (fig ) , and separately from all recognized sapovirus genogroups (gi to gv) and other unclassified sapoviruses. nucleotide sequence comparison between strains within the african wild carnivore group and other sapoviruses revealed low nucleotide similarity, ranging from . % ± . with two domestic dog strains to . % ± . with sequences from genogroup gii strains. at the amino acid level the highest similarity was with strains within genogroup giv ( . % ± . ) and the lowest with strains from one bat species in asia ( . % ± . ). nucleotide sequence comparison with members of other genera in the calicivirus family known to infect carnivores also showed low similarity values (feline and canine calicivirus; . % ± . and . % ± . , respectively, norovirus from a captive african lion; . % ± . ). within the group of african wild carnivore strains, the sapovirus strains from spotted hyenas grouped together and separately from those obtained from african lions and bat-eared foxes (fig ) . one strain from a member of the p clan (all from members of the p study clan), all the clusters contained variants obtained from members of at least two of the three study clans. notably, one variant obtained from a bat-eared fox in was placed separately from those obtained from spotted hyenas in that same year, but close to the three variants obtained in from african lions. comparison of nucleotide sequences revealed that the average similarity between all strains from spotted hyenas ( . % ± . ) was lower than between strains from african lions and bateared foxes ( . % ± . ). the percentage similarity from the variant in placed separately from the other spotted hyena variants was lower ( . % ± . ) than that of all the other spotted hyena variants that grouped more closely ( . % ± . ). however, comparison at the amino acid level revealed that all strains from spotted hyenas were identical. the average similarity of the sequences from african lions and bat-eared foxes was . % ± . (with differences at two amino acid positions). the average nucleotide and amino acid similarity between the spotted hyena strains and those from african lions and bat-eared foxes was . % ± . and . % ± . , respectively. overall, sapovirus infection prevalence (combining results from fecal and tissue samples) in spotted hyenas was . % ( / samples, table ). infection prevalence between and (fig ) fluctuated substantially between years (log likelihood ratio = . , df = , p < . ). we considered infection prevalence in any given year equal to or above % as indicative of an outbreak of sapovirus infection in that year. by this definition, , , , , were considered 'outbreak years' , and , , , were considered 'non-outbreak years' in which infection prevalence was below %. of the partial rdrp gene sequences obtained from spotted hyenas, of these were from outbreak years, three were from non-outbreak years and two were from years that could not be classified ( ). in the phylogenetic tree strains from non-outbreak years clustered with those from outbreak years (fig ) . to determine whether the prevalence of sapovirus infection was affected by age, we screened feces from animals in different age categories (i.e., cubs, subadults and adults). we found no significant differences in infection prevalence between different age categories across all years (chi square test, likelihood ratio = . , df = , p = . ), in non-outbreak years (likelihood ratio = . , df = , p = . ), or outbreak years (likelihood ratio = . , df = , p = . ). we screened for sapovirus rna in feces obtained from individuals on two separate occasions (s table) . of these, individuals were sampled on at least three separate occasions, and from five of these animals on a fourth occasion ( table ) . results revealed transitions of an individual from sapovirus rna negative to positive and transitions from positive to negative. in many cases the infection status did not change between sampling dates, for both initially negative (negative to negative, cases) and initially positive individuals (positive to positive, cases). we found no cases of transitions from positive to negative to positive ( table ) . transition intervals were similar between first and second, second and third, and third and fourth sampling date (kruskal-wallis test, h = . , df = , p = . ). we therefore analyzed the relationship between the duration of time intervals between successive samples and changes in infection status without regard to the number sampling repeats per individual. the duration significantly varied between different categories of changes of infection status (survival analysis, log-rank test, log-likelihood ratio = . , df = , p = . ). similar intervals were observed for changes in infection status from negative to positive (mean: . days, % c.i. . - . days, median days, n = ) and from positive to negative (mean: . days, % c.i. . - . days, median days, n = ). the shortest and longest intervals were observed when there was no change in status: negative to negative (mean: . days, % c.i. . - . days, median days, n = ) and positive to positive (mean: . days, % c.i. . - . days, median days, n = ), respectively. we used a mixed-effects binary logistic regression model to test factors influencing the likelihood of infection in spotted hyenas (log-likelihood ratio = . , df = , p = . , n = samples from individuals with complete information). the results revealed that infection was not significantly altered by either contact rates or the extent of an individual's range ( table ). the likelihood of infection significantly declined as clan size increased: with every additional individual in the clan, clan members were . times less likely to be infected with sapovirus ( table ) . as the actual clan sizes ranged from to individuals, this implied a more than two-fold change in the likelihood of infection across the observed range of clan sizes (fig ) . correspondingly, median clan sizes were significantly lower during outbreak (median = , mean = . , with % c.i.: . - . ) than non-outbreak (median = , table . rt-pcr fecal screening results for known spotted hyenas sampled at least three dates. this is the first report of sapovirus infection in wildlife species in africa. our results extend the host species range for this genus to include the spotted hyena, african lion and bat-eared fox. prior to our study, sapovirus infection in carnivores worldwide was not known from any species belonging to the felidae (including the domestic cat) [ ] , or hyaenidae, but was reported only for species in the families otariidae (californian sea lion) [ ] , mustelidae (mink) [ ] and canidae (domestic dog) [ ] . our phylogenetic analysis based on partial rdrp gene sequences revealed that sapovirus strains from wild carnivores in the serengeti ecosystem formed a monophyletic group that was distinct from other sapovirus strains worldwide, including strains from the three previously identified carnivore hosts (fig ) . strains from spotted hyena formed a separate sub-group from those obtained from african lions and bat-eared foxes, even within the same sampling year (fig ) , suggesting that strains circulating in the spotted hyena population are distinct from those in the african lion and bat-eared fox populations. evidence for a degree of species- specificity in host range is apparent in other viruses of carnivores in the serengeti ecosystem. genetically distinct alphacoronavirus variants infect spotted hyenas and sympatric silverbacked jackal during the same year [ ] , genetically distinct strains of kobuvirus infect domestic dogs and wild carnivores [ ] , and during the / canine distemper epidemic in the serengeti np, genetically distinct strains circulated in non-canids (african lion and spotted hyena) and canids (domestic dog and bat-eared fox) [ ] . more extensive characterization of sapovirus strains infecting carnivore species in the serengeti ecosystem would clarify their host range and help identify which species in the large carnivore guild are infected with sapovirus. currently it is not known whether or not domestic dogs and domestic cats in africa are infected with sapovirus. our results support the conclusion of previous studies, which emphasize the importance of long-term monitoring when documenting the genetic diversity of sapovirus strains [ , , ] . clearly we would have detected far less genetic diversity in our partial rdrp gene sequence data had our sampling of spotted hyenas been limited to a time frame of one or two years (fig ) , and particularly if sampling was (by chance) only undertaken during non-outbreak years when infection prevalence was low (fig ) . samples obtained during outbreak years revealed considerable genetic diversity; for example from to we obtained sequence data from five different variants, including the distinct variant (kt ) which was the least similar to all others from this host species. as we were not able to sequence data from all rt-pcr positive samples, we cannot exclude the possibility that the genetic diversity among spotted hyena strains was higher than our results indicate. even so, in line with a previous study [ ] , our result show that sequence data from the non-structural rdrp gene yields useful information on the genetic diversity of circulating sapovirus strains. some outbreaks of sapovirus infection in humans can be linked to the emergence of specific genotypes [ , , ] , suggesting that herd immunity against prevailing genotypes may be evaded by the emergence of genetically novel strains. our long-term monitoring of sapovirus infection in spotted hyenas revealed significant changes in yearly prevalence during the study (fig ) and the occurrence of three outbreaks of infection. the highest infection prevalence (above . %) occurred during an outbreak from to , whereas infection prevalence in two later outbreaks (from to and in ) was considerably lower. presumably the / sapovirus outbreak induced herd immunity to the genetic strains that circulated in spotted hyenas during this period, but our phylogenetic analysis (fig ) did not reveal the emergence of genetically distinct strains in response to this. even so, our partial sapovirus rdrp gene sequence data are insufficient to draw strong conclusions. for this, a more extensive genetic investigation is needed, particularly using the vp gene used to place sapoviruses in genogroups [ , ] , that may reflect the antigenic relationships between sapovirus [ ] . overall sapovirus infection prevalence in spotted hyenas ( . %) in the serengeti np was several magnitudes higher than the prevalence reported for the domestic dog (< %) [ , ] and the bat h. pomona ( . %) [ ] . moreover, our long-term monitoring reveals that infection prevalence in spotted hyenas was typically high, being above % in most years (fig ) . there has been much discussion about the effect of human age on sapovirus infection (reviewed by [ ] ), mostly based on studies on individuals with gastrointestinal infections. however, there is growing evidence from research on humans with and without clinical symptoms which demonstrates sapovirus infection across a wide range of ages [ ] , including elderly people [ ] . our results on sapovirus infection across different age categories indicate that the likelihood of infections in spotted hyenas was not significantly influenced by age ( table ) . the long-term perspective of our study allowed us to assess the sapovirus infection status of several individually known spotted hyenas on different sampling dates. several animals transitioned from positive to negative, and we interpret this to indicate that they successfully cleared the virus following infection. if, following an initial infection, spotted hyenas gained long-term immunity against further infection, infection prevalence should decline with age. as prevalence amongst adults reached almost % during outbreak years, our results do not provide strong evidence for long-term immunity in this species (table ) . even so, we found no individual that changed from rt-pcr positive to negative to positive (table ) which would have provided direct evidence of re-infection. during outbreaks of sapovirus in humans and pigs, cases of re-infection with sapovirus belonging to different genogroups have been reported in both species, suggesting genogroup-specific immunity for sapoviruses [ , , ] . more extensive investigation of the genetic diversity across strains circulating in our spotted hyena population is needed to determine whether sapovirus strains induce ( ) short-term immunity, which would permit re-infection with strains from the same sapovirus genogroup, ( ) genogroup-specific immunity, in which re-infection would involve strains from different genogroups, or ( ) possibly a complex interplay between the two, as hypothesized for the genetically and antigenically diverse norovirus which is closely related to the sapovirus genus [ , ] . interestingly, infection status depended on the length of time between repeated samples. animals that were negative on two separate dates (table ) had the shortest median period between sampling dates ( days), those that changed from negative to positive ( days) and from positive to negative ( days) had an intermediate median number of days, whereas animals that were positive on both sampling days ( days) had the longest median period. taken together, these results suggest that when a spotted hyena is infected, infection is cleared, and reinfection is unlikely within a period of several months, which is consistent with the idea that exposure to sapovirus does not provide long-term immunity against further infection. in humans, sapovirus shedding often subsided days after the onset of illness [ ] , but can persist for up to days [ ] . hence, we speculate that the spotted hyenas which were positive on two sampling dates several months apart were animals that were re-infected rather than individuals with persistent long-term infections. however, currently we cannot exclude the possibility that there may be spotted hyenas that shed sapoviruses for periods spanning several months. spotted hyena social and ranging behavior has been shown to structure transmission routes and the likelihood of infection by a broad range of pathogens [ , [ ] [ ] [ ] [ ] ]. yet when we tested whether these two factors influenced sapovirus infection in this species, neither the predicted effect of contact rates based on known patterns of greeting ceremonies, nor the extent of an individual's range significantly influenced the likelihood of infection in our study population (table ) . clan size was a significant factor, but contrary to our expectation, the likelihood of infection declined with increasing clan size. this phenomenon is known in the behavioral literature as the attack-abatement effect [ ] or as the encounter-reduction effect [ , , ] . in multi-species host assemblages the same phenomenon in the ecological literature is termed a 'dilution' effect. at least five non-exclusive mechanisms have been identified [ ] that can cause a reduction in infection incidence as the number of host species increases, but not all of them are relevant to intraspecific sapovirus infections in spotted hyenas. we have no evidence that sapovirus infection increases the death rate of infected individuals (mechanism ), as no obvious clinical signs are associated with sapovirus infection in most spotted hyenas. although we lack a precise measure of the recovery rate (mechanism ), the general absence of obvious clinical signs of sapovirus infection suggest that the recovery rate is already very high, so that a change in this factor is likely to be modest. a decrease in the density of susceptible individuals (mechanism ) is unlikely unless this results from a substantial increase in the proportion of clan members immune to sapovirus infection, even if immunity is relatively transient. a substantial increase in the prevalence of immune clan members would result in far fewer sapovirus susceptible individuals. moreover, such an increase in herd immunity would probably also lead to a decrease in the prevalence of sapovirus excreting clan members, thereby reducing the probability of: ( ) sapovirus transmission per encounter (mechanism ) between clan members and ( ) the encounter rate between susceptible and infectious individuals (mechanism ) in a clan. further research and more detailed modeling of the interplay between clan size and the prevalence of clan members in different sapovirus infection states (susceptible, infected/excreting virus, and immune) is required to test this idea. in the context of our study, mechanism (encounter rate between susceptible and infectious individuals) is similar to mechanism (decrease in the density of susceptible individuals) because a reduced density of susceptible clan members caused by a rise in the prevalence of transient immunity would also curb the number of infected animals in a clan and may prevent their number growing in proportion to increasing clan size, and possibly holding them at or below a fixed number (threshold). an increase in the risk of internal pathogen infection with a decrease in a group size component has been reported by other studies [ , ] . as sapoviruses cannot be cultured, with the exception of the strain pec cowden [ , ] , knowledge of viral tropism and the receptor use for entry to host cells is limited. moreover, sapovirus typically infects intestinal tissue and to our knowledge is not known to infect other tissues, as illustrated by the absence of viral rna in any extra-intestinal tissues in gnotobiotic pigs inoculated with pec cowden [ ] . however, in a few dead spotted hyenas (typically road casualties) from which we opportunistically obtained tissue samples, we detected sapovirus rna most often in the spleen and occasionally also in lymph nodes, intestines and the liver. to our knowledge this is the first report of sapovirus rna in extra-intestinal tissues following natural infections. the possibility that sapoviruses disseminate to extra-intestinal tissues may be of clinical importance [ ] . notably, in asymptomatic mice shedding murine norovirus in feces, viral rna was also found in several extra-intestinal organs, including the liver, spleen and lymph nodes [ ] . studies on caliciviruses infecting wild carnivores have focused on feline calicivirus (fcv, genus vesivirus, family caliciviridae). for example, serological surveys documented that african lions [ ] and spotted hyenas in the serengeti ecosystem were exposed to fcv [ ] with a high prevalence. our phylogenetic analysis shows that the variants we report from wild carnivores in africa are distinct from both fcv and canine calicivirus (fig ) . a norovirus (genus norovirus, family caliciviridae), genetically related to human noroviruses was reported from a captive african lion [ ] and subsequently identified in domestic dogs and domestic cats [ , ] . combining these findings with our results suggests that the spotted hyena and african lion can be infected by viruses belonging to three different genera of the family caliciviridae. we provide the first report of sapovirus infection in wild carnivore species in africa, including the spotted hyena, african lion and bat-eared fox. long-term monitoring revealed considerable genetic diversity of variants from these species which were phylogenetically distinct from previously reported sapovirus strains from other geographical areas worldwide. sapovirus prevalence in the spotted hyenas varied between years and was not influenced by age. an individual's likelihood of infection significantly declined with increasing group size, consistent with an encounter reduction effect. our results reinforce the importance of long-term studies in viral epidemiology of wild species. supporting information s emerging infectious diseases of 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(crocuta crocuta) in the masai mara national reserve norovirus in captive lion cub (panthera leo). emerg infect dis detection and molecular characterization of a canine norovirus discovery and genomic characterization of noroviruses from a gastroenteritis outbreak in domestic cats in the us key: cord- -vz qvp authors: chitray, m.; de beer, t. a. p.; vosloo, w.; maree, f. f. title: genetic heterogeneity in the leader and p -coding regions of foot-and-mouth disease virus serotypes a and o in africa date: - - journal: arch virol doi: . /s - - - sha: doc_id: cord_uid: vz qvp genetic information regarding the leader (l) and complete capsid-coding (p ) region of fmd serotype a and o viruses prevalent on the african continent is lacking. here, we present the complete l-p sequences for eight serotype a and nine serotype o viruses recovered from fmdv outbreaks in east and west africa over the last years. phylogenetic analysis of the p and capsid-coding regions revealed that the african isolates grouped according to serotype, and certain clusters were indicative of transboundary as well as intra-regional spread of the virus. however, similar analysis of the l region revealed random groupings of isolates from serotypes o and a. comparisons between the phylogenetic trees derived from the structural coding regions and the l region pointed to a possibility of genetic recombination. the intertypic nucleotide and amino acid variation of all the isolates in this study supported results from previous studies where the externally located d was the most variable whilst the internally located a was the most conserved, which likely reflects the selective pressures on these proteins. amino acids identified previously as important for fmdv structure and functioning were found to be highly conserved. the information gained from this study will contribute to the construction of structurally designed fmdv vaccines in africa. electronic supplementary material: the online version of this article (doi: . /s - - - ) contains supplementary material, which is available to authorized users. foot-and-mouth disease (fmd) is a highly contagious disease that affects domestic and wild cloven-hoofed animals [ , ] . despite all the information accumulated over the years on many aspects of fmd basic biology, there is still a lack of information regarding fmd virus transmission, maintenance, virulence and host range. although fmd is referred to as a single disease [ ] , the causative agent of the disease, fmd virus (fmdv), consists of seven immunologically distinct serotypes [ , ] . the fmdv serotypes, i.e., a, o, c, asia and the south african territories (sat) types , and , have different global geographical distribution patterns [ - , , , , ] and are endemic in many countries. even on the african continent, the distribution of serotypes is variable, with the sat serotypes occurring in most regions of sub-saharan africa but a and o confined mostly to the central and northern parts of the region [ ] . mortality is usually low, but morbidity can reach % and therefore remains a major economic concern for livestock health in many developing countries and a continued threat to disease-free countries [ ] . the eradication and control of fmdv in africa is complex and difficult due to the role of wildlife in virus spread and maintenance [ ] and the presence of six of the seven serotypes, i.e., a, o, c, sat , sat and sat . serotype c has not been reported since [ ] . fmdv is a non-enveloped virus containing a singlestranded rna genome of positive polarity in the genus aphthovirus of the family picornaviridae [ , , ] . the large open reading frame (orf) of * , nt, which differs in length between the different serotypes [ ] , encodes a single polypeptide, which is co-and posttranslationally cleaved by viral proteases to give rise to the structural and non-structural proteins [ , , , ] . ten of the cleavage events are catalysed by the virally encoded c protease [ , , , ] . translation takes place from a single open reading frame by a cap-independent mechanism at the internal ribosome entry site (ires) [ ] , located in the ' untranslated region (utr). there are two different sites on the rna at which the initiation of protein synthesis occurs, resulting in the generation of two forms of l proteinase (l pro ), lb and the less abundant lab, where lb is the truncated version, which arises after the initiation of translation at the second aug start codon [ ] . lab and lb can cleave the l/p junction and ensure the proteolytic degradation of the cellular cap-binding protein complex (eif g), which results in the shutoff of host translation [ ] . the p region is the viral capsid precursor and consists of the proteins a (vp ), b (vp ), c (vp ) and d (vp ). the antigenicity of the viral particles is dependent on the amino acid (aa) residues that are exposed on the surface of the capsid [ , ] . furthermore, it has been shown that the external capsid proteins play a role in binding to the fmdv cell-surface receptors, i.e., the rgddependant integrins [ , , - , , ] and heparan sulphate proteoglycans (hspgs) [ , , ] . the genetic heterogeneity of the virus, which is due to the lack of a proofreading mechanism during virus replication, has resulted in the occurrence of extensive variability as well as different lineages and antigenic variants within a serotype that have established themselves in different geographical regions [reviewed in refs. - , , , , , , ] . this has resulted in the need for multiple vaccine strains required for each serotype to cover the antigenic diversity when using vaccination as a control option [ ] . in africa and countries bordering europe, the disease is mainly controlled using vaccination and restriction of animal movement. thus, it is imperative to obtain as much information as possible regarding the fmdv prevalent on the african continent to further our knowledge on fmd epidemiology, define genetic relationships of viruses causing outbreaks [ , ] and to enable better control strategies by successful vaccine development. genetic information regarding the leader (l) and complete capsid-coding (p ) region of serotype a and o viruses prevalent on the african continent is lacking, although the sat isolates have been broadly studied in the past [ ] [ ] [ ] ] . for this study, the l and p coding regions for eight fmdv a and nine fmdv o viruses isolated between and were successfully sequenced and analysed using phylogenetic analysis, examination of sequence variability, and identification of highly conserved genomic regions relating to previously identified fmdv functional and structural biological capabilities. non-conservative substitutions were mapped to the available o (o bfs) [ ] and a (a /hol/ ) [ ] capsid structures, and amino acid substitutions that may be involved in antigenic divergence were identified. the sub-saharan african isolates included in this study belong to different topotypes of fmdv serotypes a and o as defined by d sequencing and represent a broad geographical distribution of viruses within east and west africa. the nine fmdv serotype o isolates and eight serotype a isolates were obtained from the institute for animal health, pirbright laboratory, pirbright, united kingdom (table ) . for the purpose of analysis, a select few complete l and p fmdv sequences currently available in genbank were included (table ) . the fmdv type o viruses were passaged for a previous study and were used directly in this study for processing, whereas the fmdv a isolates were first propagated on ib-rs- cells (instituto biologico renal suino cell line, a pig kidney cell line) to obtain a high viral titer. the ib-rs- cells were maintained in rpmi medium (sigma) supplemented with % foetal calf serum (fcs; delta bioproducts) and x antibiotic-antimycotic ( , gibcoÒ), invitrogen). virus was added to prepared cells containing rpmi supplemented with % (v/v) fcs and antibiotic-antimycotic mixture and incubated at °c until complete cpe was attained (after h). clarified cell culture supernatant containing virus was stored at - °c until further use. chinese hamster ovary (cho) cells strain k (atcc ccl- ) were maintained in ham's f- medium (invitrogen) supplemented with % fcs. plaque assays were performed by infecting monolayer cells with the virus for h, followed by the addition of a -ml tragacanth overlay [ ] and staining with % (w/v) methylene blue [ ] . total viral rna was extracted using a modified guanidinium thiocyanate (guscn)-silica method [ ] . the viral rna template was reverse transcribed at °c for h using u of amv reverse transcriptase (promega) and the antisense p primer (wda; '-gaagggcccaggg ttggactc- ') [ ] as described previously [ ] . amplification of the l-p region was undertaken using the antisense p (wda) primer and the sense ncr primer ( '-taccaagcgacactcgggatct- ') followed by pcr reactions using long-template taq dna polymerase (roche) and thermal cycling conditions described by van rensburg et al. [ ] . pcr products of ca. , bp were excised from a % agarose gel and purified using a nucleospin Ò extract kit (macherey-nagel). purified pcr products were sequenced using a genome-walking approach with genome-specific oligonucleotides and an abi prism tm bigdyeÒ terminator cycle ready reaction kit v . (applied biosystems). sequences were analysed using an abi prism genetic analyser (applied biosystems). ambiguous nucleotides (nt) of the l-p sequences were resolved manually and assembled into a contig using the sequencher tm . dna sequence analysis software (gene codes corporation, ann arbor, mi, usa). a consensus sequence representing the most probable nt for each position of the sequence was obtained for each isolate. consensus sequences were translated in bioedit . . dna sequence analysis software [ ] , and the complete l-p nt and aa sequences were aligned using clustalx . . [ ] . hypervariable regions in the complete aa alignment were defined as a linear -aa region containing more than % variable residues. the phylogenetic analysis included the newly determined sequences as well as sequences of non-african serotype a and o isolates obtained from genbank (table ) . maximum-likelihood analysis of the aligned sequences was carried out in paup [ ] under the aikake information criterion. phylogenetic trees were constructed using the neighbour-joining (nj), minimum-evolution (me) and maximum-parsimony (mp) methods included in the mega . program [ ] for the l, a, b, c, d-coding regions separately as well as the full p -coding region. node reliability was estimated by bootstrap replications for nj, me and mp trees, whilst the nucleotide substitution model of kimura -parameter was employed for the nj and me trees and close-neighbour-interchange (cni) with search level in effect for the mp and me trees. mega . [ ] was utilised to determine the nt and aa variation. plots representing the aa variation, hydrophobicity and secondary structures for each protein were drawn using python (http://python.org) and the matplotlib package (http:// matplotlib.sourceforge.net). the number of different amino acids occurring at a specific position was used as a measure of variation, and the hydrophobicity scale of kyte and doolittle [ ] was used to measure relative aa hydrophobicity. the crystallographic protomers of the capsid proteins of o bfs ( fod) [ ] and a /hol/ (( zbe) [ ] were visualized and the surface-exposed residues identified with pymol v . rc pre (delano scientific llc). phylogenetic trees based on the p (fig. ) (fig. ) , the latter belonging to the middle east-south asia (me-sa) topotype based on d phylogeny [ ] . the exception is o/sar/ / , which was isolated in south africa in during an outbreak caused by illegal feeding of swill to pigs [ ] . (fig. ) . furthermore, these p groupings were also observed when me and mp phylogenetic models were utilised (not shown). clustering similar to that of the p region was observed for the separate gene regions, but with low bootstrap support except for b ( (fig. ) . the nt sequence differences in the p -coding region between members of each topotype were typically more than %, similar to the cutoff defined for a topotype [ ] . globally, fmdv serotype a exists in three geographically distinct topotypes, asia, africa and europe-south america (euro-sa), based on the genetic relationships of d sequences [ ] . using the sequence information of the african a isolates together with p sequences of serotype a viruses available in the genbank database, at least two separate clusters were observed for the type a viruses, i.e., non-african and african a isolates, supported by % bootstrap values for all phylogenetic methods used for the p (fig. ) , b, c and d gene regions (supplementary data, s -s ). two east african isolates, a/tan/ / and a/som/ / formed a well-supported subgroup for the p (fig. ) and d nj trees (supplementary data, s ). in addition, there was a consistently strong grouping for three west african isolates, a/nig/ / , a/civ/ / and a/sen/ / , in the p (fig. ) , b, c and d nj analyses (supplementary data, s -s ). the serotype a non-african and african viruses displayed similar genetic variability when compared to serotype o. the intratypic nt sequence variation in an alignment of the -nt p -coding region for type a was calculated to be . %, whilst the corresponding region ( - nt) of type o only revealed . % variable nucleotides. analysis of the a gene region resulted in phylogenetic groupings that differed from those of the p , b, c and d analyses. when performing phylogenetic analysis on the combined o and a dataset, the fmdv a and o isolates did not group strictly according to serotype (supplementary data, s ). for example, three non-african fmdv a strains, isolated from brazil and venezuela (a /agua-rulbos/iso , a /zulia/iso and a /brazil/ iso ), grouped with o viruses from the me-sa, sea and ea topotypes, but with low bootstrap support. as expected, the region encoding a was the most conserved, exhibiting . % variant nucleotides and was the only capsid-coding region with the highest average %ts/tv rate of . % ( table ). in contrast, d had the highest variability of . % and lowest average %ts/tv rate of . % ( table ) . the phylogenetic trees based on the l pro -coding region for the combined serotype o and a dataset had similar tree topologies for the a and o isolates, independent of the phylogenetic methods employed. the nj tree of the l procoding region (fig. ) showed that the viruses did not group strictly according to serotype, in contrast to those areas of fmdv hydrophobicity and aa variation are represented by blue and green lines, respectively. regions of variability or hypervariable sites were defined as sites on the p that had five or more variable aa residues within a window of residues based on the structural proteins. the non-african a and o isolates that form a part of the euro-sa lineage [ ] formed separate subgroupings in the l pro -coding sequence nj tree (fig. ) . the pan-asian isolates formed a separate grouping with high bootstrap support ( % the l pro aa sequence displayed significant variation for a functional protein: . % for the serotype a alignment and . % for the serotype o isolates (table ) . at least . % ( of aa) of the aa residues were variable in the alignment of the structural proteins (translated from the p region) of the serotype a isolates, whilst the (table ) . a systematic analysis of the capsid proteins revealed the variation not to be random but focused in local regions of hypervariability. the most variable capsid region, d, displayed the most regions of hypervariability. figure a shows the hypervariable regions of type o at aa positions - , - , - , - , - . at least seven discrete hypervariable regions ( - , - , - , - , - , - , - ) were identified in d of type a (fig. b) . the conserved n-terminal motif of b, dkkteettl-ledril-ttrnghttsttqssvg, described by carrillo et al. [ ] , was present in the african a and o sequences (results not shown). two hypervariable sites, residues - within the bb-bc loop and - in the be-bf loop, were mapped within b of type o (fig. c) . b of type a displayed the same two hypervariable regions, residues - and - , and a third hypervariable region, - (bh-bi loop; fig. d ). most of the c aa substitutions for type o were concentrated in one hypervariable region, i.e. - . a second region with significant variability worth mentioning was residues - , where three residue positions displayed high entropy and were located within a surface-exposed loop of c (fig. e) . the latter was situated in the b-b 'knob' of c and included the epitope site for serotype o [ ] . at least three hypervariable regions were identified in the type a alignment, i.e. residues - , - and - (fig. f) . the a protein of serotype o was most conserved, with only four variable residues and hypervariable regions that were not common for a (not shown). the amino acids that have previously been identified as critical for fmdv were compared to the complete aa sequence alignment of the african and non-african a and o isolates from this study and are summarized in supplementary data s , showing that the aa residues important for fmdv function are conserved. [ ] and fry et al. [ ] confirmed the importance of the r residue of c for hs binding and cell culture adaptation. fmdv plaque assays in cho-k cells (table ) confirmed that o/ken/ / was the only virus that was able to infect and replicate in this cell line. taking all of the serotype o capsid-sequence data together, of the o isolates had a his residue at position of c, and they might therefore require integrins to replicate in cell culture. amino acid sequence variation in relation to structure vaccines based on a /iraq/ , a/eri/ and o manisa are recommended for the control of fmd in africa [ ] . we examined the variation within the deduced amino acid sequences of the capsid proteins of the african o and a isolates and compared the surface-exposed regions with those of the three recommended vaccine strains. regions with high aa variability in an alignment of the capsid proteins were mapped onto the x-ray crystallographic structures of type a (a /hol/ ; qqp) [ ] and o (o bfs; fod) [ ] viruses. figure shows that the regions of variability were mostly located on surfaceexposed regions of the virion. not all of the aa side chains within a variable region were exposed on the surface. closer inspection of each aa position within a region of hypervariability indicated that positions with high variability had side chains exposed to the microenvironment of the virion. for serotype a viruses, most of the hypervariable regions outside the d bg-bh loop were concentrated around the -fold and -fold axes of the virion and the c-terminus of d (fig. ) and correlated to a large extent with residues previously found to be involved in escape from neutralization by monoclonal antibodies (table ) . furthermore, many of the putative epitopes were probably discontinuous. for example, there was close proximity of b residue and c residues - and - around the -fold pore of the virion (fig. ) . similarly the regions of variability for type o correlated strongly with epitopes previously identified with distribution around the -fold and -fold axes of the virion ( fig. ; table ). the data from the analysis of the complete capsid-coding region, p , as well as the individual capsid-coding regions indicated that very similar tree topologies existed for the different genomic regions when comparing the african a and o viruses with those from other regions of the world. in general, analysis of the entire structural protein-coding region improved bootstrap values relative to d analysis alone. the longer the capsid-coding region included in the analysis, the more accurate the relationship conclusion. this supports the view that sequencing of the entire capsidcoding region, rather than d alone, is desirable in molecular evolution studies. phylogeny based on the nj trees of the p , b, c and d sequences resulted in the grouping of viruses according to serotype. in addition, the a and o virus clusters could be further divided into separate groupings of the african and non-african a and o isolates, which were observed for the p , b, c and d nj, me and mp trees. the separate groupings of the african and non-african a viruses support previous findings for type a viruses. these could be grouped into three major restricted genotypes, i.e., euro-south america, asia and africa, based on d phylogeny (this study only included fmdv a viruses from euro-south america and africa) [ , , ] . similarly, based on d phylogeny, type o viruses were divided into three groups: those originating from asia, europe-south america and the far east [ , , , ] . the p phylogeny therefore supports the three major virus groups within serotype o. the eastern and western african o viruses were grouped together with the sea and me-sa lineages, together with the pan-asia strain [ , , ] , albeit as lineages restricted to geographic regions (east africa- , , , and west africa). furthermore, the phylogeny is indicative of the transboundary spread of fmdv in africa among the east african countries, uganda, kenya, somalia and tanzania, that are in close proximity to each other, which is also true for the west african countries, i.e. nigeria, ivory coast and senegal. the groupings also indicated that the east african and west african viruses fall into separate large groups. another well-supported grouping was observed for the p , b and c trees (all methodologies) for o/uga/ / , o/uga/ / and o/uga/ / , with a maximum of . % nt and . % aa substitutions in any pairwise alignment. this grouping most likely signifies that the outbreak strains re-emerged from older strains that have been maintained in the endemic area since the early s, i.e. from to ( years). there was a difference in the groupings for the a trees when compared to the p and other capsid-coding gene regions where three non-african a isolates clustered with the non-african o viruses (for all phylogenetic methodologies). the phylogenetic tree representing the region encoding the l protein differed from that of the structural proteins where sub-grouping according to serotype was much less apparent, which was consistent with previous findings for this region [ , ] . interestingly, certain a and o african viruses clustered together and also did not separate into geographical regions such as east and west africa as observed for the structural coding regions. for example, bootstrap support of % for the l-region nj tree was observed for the grouping of o/uga/ / , o/uga/ / , o/uga/ / & a/eth/ / , which was not observed with the a, b, c, d and p phylogenetic analysis. this suggests that the african viruses share similarities or are closely related when comparing the l sequences, irrespective of serotype. taking into account the extensive, uncontrolled movement of animals across the borders and the ease of virus spread and infection of multiple serotypes in one animal, the role of recombination events in the genetic diversification of fmdv cannot be excluded. although we did not perform a study on the occurrence of recombination, the similarities present between fmdv a and o l sequences could be due to the occurrence of intertypic recombination events [ , [ ] [ ] [ ] ] . due to the high mutation rates of fmdv, it is likely that even brief epidemics might result in the generation of substantial antigenic variability [ ] . however, the adaptive significance of this variation remains unclear [ ] . the antigenicity of fmdv is attributed to the aa residues that are exposed on the surface of the capsid [ ] . an important immunogenic determinant, the d g-h loop [ ] , exhibited a high degree of variation for the a and o isolates included in this study. consequently, aa changes in this region are most likely involved in the appearance of novel antigenic types. analyses of antigenic sites of picornaviruses have been carried out using neutralising monoclonal antibodies (mabs) to select and screen mab-resistant mutants. sequence analysis of these mutants resulted in the identification of five antigenic sites of serotype o virus, i.e., o kaufbeuren [ , ] , and six sites for the fmdv a viruses [ ] . alignments of the aa sequences of the african a and o viruses indicated that the regions of variability identified corresponded to the known antigenic sites, which points to the fact that the location of antigenic sites are structurally conserved for the african a and o viruses. in addition to these sites, other regions of variability were identified for both the fmdv o and a african isolates from the aa variability plots. these regions could potentially be antigenic determinants, which may be difficult to map by the classical methodology of mab-resistant escape mutants. we have recently shown that an approach combining sequence variation with structural data and antigenic variation results in the reasonably accurate identification of novel antigenic determinants on the virion surface [ ] . the aligned l pro aa sequences displayed marked variation in both the lab and lb regions (not shown); however, despite this variation, the aa residues identified as being critical for the l pro function were highly conserved, i.e., the residues c , h and d required for l pro catalytic activity, the e residue required for l pro autocatalysis, and two his residues (h and h ) important for cleavage of the translation initiation factor, eif g, [ , , , ] . a comparison of the l/p cleavage sequence at the c-terminus of the l protein and n-terminus of the a protein of the fmdv non-african a types revealed a sequence of r(q/w)klk*gagq (* indicates cleaved peptide bond), whereas the african a types included in this study had the sequence k(r)r(k)lk*gagq (results not shown). both the fmdv non-african and african o types revealed a sequence of (k/r)(k/r)l(k/r)*gagq (* indicates cleaved peptide bond) (results not shown). these observations compared well with the l pro / a junction previously described for serotypes a, o and c [ ] , where the residues k(r)r(k)lk(r) at the l pro c terminus and the gagq at the a n terminus were observed. these results suggest that for all the a and o types included in this study, the conserved sequence xxlk(r)*gagq (where x is either k or r) is sufficient for l/p cleavage by l pro . the degree of hydrophobicity/hydrophilicity of the loops connecting the b chains varied between the african a and o surface proteins. hydrophilic b-b loops tend to be exposed on the protein surface, sometimes protruding from the protein core, and are candidates for antibody binding [ ] . overall, the aa sequence variation observed for the fmdv a and o viruses included in this study showed that the a viruses exhibited more variation, possibly indicating that the a viruses evolved rapidly, which supports studies by bachrach [ ] and brooksby [ ] . additionally, tully and fares [ ] showed that among all of the fmdv serotypes, serotype a is the most divergent and that adaptive evolution has occurred in the c protease (involved in rna replication and processing of the polyprotein) and b (involved in membrane rearrangements), which supports the hypothesis of selection for faster replication in serotype a. neff et al. [ ] showed that a variant of the type o virus containing an arg at residue of c required only hs binding to replicate in cho-k cells but that another variant with a his residue at this position required integrins to replicate in cell culture. interestingly, in this study, it was shown that o/ken/ / was the only african virus to have this arg residue at residue of c, and it was indeed able to replicate in cho-k cells. however this virus has been passaged three times on ib-rs- cells, and it is possible that the mutation arose during cell culture passage. additionally, various aa residues that were previously identified as important for playing a role in various functions for fmdv were found to be conserved for the a and o isolates (see ''results''). it is clear from the outbreaks of fmd during the last two decades that there is a continuing threat to the livestock industry. the results presented here show distinct geographical grouping of serotype a and o viruses in africa, although common ancestry with the euro-south american-asian topotypes is clear. the natural diversification of fmdv occurs during replication in infected animals and results in the rapid generation of mutants and the ability to persist and to spread amongst livestock. thus, continuous surveillance and an active molecular epidemiology program increases our knowledge with regard to fmdv phylogenetic relationships, virus antigenicity, and the ability of existing vaccine strains to provide protection against emerging and re-emerging viruses. the pathogenesis and diagnosis of foot-and-mouth disease foot-and-mouth disease robertson bh ( ) foot-and-mouth disease virus: immunogenicity and structure of fragments derived from capsid protein vp and of virus containing cleaved vp multiple virulence determinants of foot-andmouth disease virus in cell culture neutralization epitopes of type o foot-and-mouth disease virus. i. identification and characterization of three functionally independent, 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selection-drift balance drive the evolution and epidemiology of foot-and-mouth disease virus lymphocyte recognition elements on the vp protein of theiler's virus genetic heterogeneity in the foot-and-mouth disease virus leader and c proteinase a similar pattern of interaction for different antibodies with a major antigenic site of foot-and-mouth disease virus: implications for intratypic antigenic variation review of the status and control of foot and mouth disease in sub-saharan africa sequencing and analysis for the full-length genome rna of foot-and-mouth disease virus china/ genetic heterogeneity of fmdv african types a and o acknowledgments this work was supported by the sa-uk collaboration initiative via the department of science and technology. the authors would like to express their gratitude to the personnel at the arc-ovi (tadp) for their contributions to virus isolation. we would like to thank dr. b. blignaut for assistance with plaque titrations. we also gratefully acknowledge dr. o. koekemoer, dr. m. van kleef and dr. n. singanallur for critical reading of the manuscript.open access this article is distributed under the terms of the creative commons attribution license which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. key: cord- -ojfm rt authors: langan, jennifer n.; jankowski, gwen title: overview of african wild dog medicine date: - - journal: fowler's zoo and wild animal medicine current therapy, volume doi: . /b - - - - . - sha: doc_id: cord_uid: ojfm rt nan the african wild dog (lycaon pictus)-also referred to as the african hunting dog, painted dog, and cape hunting dog-is one of africa's most endangered carnivores. owing to its decreasing numbers, it holds an international union for conservation of nature (iucn) red list priority status for the conservation of canid species in africa. african wild dogs were formerly distributed throughout sub-saharan africa but are now mostly confined to southern africa and the southern portion of east africa (fig. . ). , they require large ranges and live at low population densities. the population is currently estimated at animals and continues to decline as a result of ongoing habitat fragmentation, conflict with humans, and infectious disease. , predation by lions and competition with spotted hyenas also contribute to population suppression. there are approximately african wild dogs in zoos, which serve to educate the public and fulfill an important role as ambassadors aiding the recovery effort for this species. the african wild dog is a member of the family canidae in the order carnivora; it likely diverged from wolves in the pleistocene period. genetic studies demonstrate that it is sufficiently different from other canid species to warrant being classified into a separate genus. adults weigh - kg, with males slightly larger than females. , , the average age of survival in zoos is . years ; a few animals live - years. , , the african wild dog's most striking characteristic is the tricolored spotted coat, for which it received its latin name, lycaon pictus, meaning "painted wolf." it has large round ears, lacks a supracaudal (tail) gland, has four digits on each limb (lacks dew claws), and the pads of the middle digits are connected by dermal webbing. reproductive anatomy is similar to that of domestic dogs in both males and females, but females have - mammae. they have very sharp, large premolars relative to their body mass, which allow them to consume overview of african wild dog medicine jennifer n. langan and gwen jankowski sizable quantities of meat and bone with impressive speed. the dental formula is i / , c / , pm / , m / = , of which the last mandibular molar is vestigial and generally not visualized. the typical wild pack is composed of an older dominant female paired with a young dominant male and subordinates of both sexes. dominant males may be displaced as they age or lose strength. juvenile males are most likely to stay with the pack, whereas females often emigrate. following the death of the dominant female, significant social changes occur within the group, which can result in pack dispersal in the wild. , social management of african wild dogs under human care is challenging and can have significant health impacts. it involves working across institutions to create and maintain packs that thrive socially, support a healthy population, and sustain genetic diversity. the most stable social groups include a well-established dominant pair with male offspring of any age and young female offspring. the inability to disperse may result in conflict between female offspring above months of age and the dominant female. the decreasing frequency of "hoo-calls" (long-distance communication calls) and distance between resting sites of same-sex groups suggest that unrelated individuals under human care are more likely to integrate into a pack successfully. if animals need to be separated due to social incompatibility, it is recommended that individuals be split up as same-sex packs or with littermates less than months of age. contraception for reproductively mature individuals intended to reduce aggression has not been successful. measurement of fecal corticosteroids may be a useful management tool and has demonstrated that dominant animals generally have the highest stress levels. [ ] [ ] [ ] behavior is a key indicator of social and physical wellbeing in african wild dogs. "normal" behavior varies by an individual's status within the pack, and establishing pack hierarchy is essential for avoiding excessive aggression. have access to multiple heated areas if the temperature regularly drops below . °c- . °c ( °f- °f) and should have shelter from the elements. additionally, a heated den should be provided if breeding is planned. facilities should have sufficient holding space to accommodate separating animals for long periods. with the exception of fish, housing african wild dogs with other species is not recommended due to their high predatory drive. african wild dogs should be moved only in sturdy metal or wood crates with good ventilation that meet us department of agriculture (usda) and international air transport association (iata) requirements for live animal transport. completing a written transport plan, health evaluation, and crate training facilitates transitions when animals are relocated. african wild dogs are generalist predators, occupying a range of habitats where they hunt medium-sized antelope. in natural settings, reduced prey populations and competition from other predators inhibit population growth. , african wild dogs in zoos are fed a nutritionally complete raw meat-based diet ( - . kg/adult/day) and are supplemented with small whole prey, knuckle/rib/shank bones (one to two times week), and carcasses (pig, deer, calf, horse). lactating bitches require up to three times permanent or even brief temporary removal of an established pack member may have profound social impacts, including changes in social hierarchy with aggression so substantial that reintroduction may not be possible. , detailed plans to reduce stress and promote normal behaviors should be implemented if a dog must be isolated, including maintaining olfactory and visual contact. if separation is required, it may be helpful to subdivide the pack and then reintroduce them all simultaneously. alternatively, introductions of subordinate dogs first, then dominant pairs, may be effective. successful implementation of enrichment has included environmental devices, sensory stimulants, and food, behavioral, and habitat variance. piles of leaves, dirt, and mulch allow natural digging and rolling behaviors. rotating exhibits with other predators provides habitat diversity and promotes scent-marking behavior. offering carcass feeds hung from trees or on zip lines, feeding bones, providing several types of enrichment to the pack simultaneously, and permitting breeding when possible are recommended for this species. , enclosures should be large and contain ample space for exercise to meet the animals' physical, social, behavioral, and psychological needs. specific size and perimeter recommendations may be found in the association of zoos & aquariums (aza) large canid care manual. facilities that allow the public to observe the animals should prevent close contact or inadvertent access to the enclosure. dogs should ah, inc., fort worth, texas). current estimates show % of females have some degree of reproductive pathology, the most frequently reported of which is cystic endometrial hyperplasia (ceh) with or without pyometra and adenomyosis ( fig. . ). [ ] [ ] [ ] adenocarcinoma, uterine rupture, and pyometra without other pathology have also been reported (kinsel, personal communication, april , ). , , the species survival plan program (ssp) currently recommends that all postreproductive females (> years) be spayed. deslorelin implants have been used for contraception and behavioral alteration in males with variable results (see table . for a summary of reproductive information) (see also chapter ) . , , healthy adult african wild dogs are not physically restrained due to safety concerns. noninvasive procedures including visual examination, hand injections, wound treatment, venipuncture, and crate training may be accomplished with operant conditioning. restraint cages are useful and provide a safe, controlled environment to facilitate intramuscular injections of anesthetics. a quiet area away from the pack promotes quick inductions and smooth recoveries. remote injection systems are recommended for immobilizing free-ranging african wild dogs or in situations when a chute is not available. anesthetic regimens selected should take into account health status, age, and environmental conditions. in cases where cardiovascular disease has been confirmed or cardiac status is unknown, alpha- agonists should be avoided and alternatives such as ketamine-midazolam-butorphanol with propofol or gas anesthesia (isoflurane, sevoflurane) should be considered. chemical restraint protocols used in african wild dogs may be found in table . and have been previously published. [ ] [ ] [ ] drug combinations at higher dosages for free-ranging african wild dogs are available in the literature. , reversal of alpha- agonists and opioids with atipamezole and naloxone decreases recovery time. to avoid dysphoria, it is advised to wait at least minutes postinduction before administering reversals. recovery in a crate or nest box may reduce struggles to stand during recovery. telazol (tiletamine hcl and zolazepam hcl, zoetis, parsippany, new jersey) as a sole agent or used in combination with medetomidine is a reliable option during an emergency response but often results in a prolonged recovery time. vascular access, intubation, and monitoring equipment are applied as in other canids. every wild dog anesthesia should include oxygen supplementation, electrocardiography (ecg), and monitoring of pulse oximetry, heart and respiratory rate, blood pressure, and temperature. as in other canids, the jugular, cephalic, and saphenous veins are commonly used sites for venipuncture. tables . maintenance caloric intake. specific recommendations for kilocalorie requirements may be found in the aza large canid care manual. feeding african wild dogs a portion of their diet while separated from the pack aids in monitoring individual animals' food consumption. packs are generally fasted from their normal meat diet day per week and may be provided with bones. african wild dogs are seasonally monoestrous obligate cooperative breeders with a brief copulatory tie. , within a pack the alpha male and female produce the majority of surviving pups annually. , , most successful reproduction occurs after years of age, with senescence around - years. , subordinate females may reproduce, but offspring typically do not survive. more often, subordinate females develop pseudopregnancy and may lactate in order to help care for the pups of the dominant pair. females produce an average of six to eight pups , and up to pups in a den after a gestation of - days. [ ] [ ] [ ] primiparous females have higher estrogen, which is reported to result in more male offspring. hand-rearing is not recommended due to the extremely aggressive and social nature of these animals. in zoos, the breeding pair is separated from the pack to prevent trauma to the pups. the group is gradually introduced when the pups begin to emerge from the nest box. a birth plan detailing responses to aggression toward the pups, large litter size, and other contingencies is recommended. newborn pups weigh about g, open their eyes around weeks of age, and emerge from the den to start taking solid food at weeks. sex determination is similar to that for other canids. pups are weaned and start to follow the pack at - weeks of age. in free-range settings, all members of the pack raise the pups; they regurgitate food while the young are in the den and relinquish kills to the pups and yearlings. , reproductive anatomy is similar to that of other canid species. owing to social dynamics, most reproduction has been natural; however, semen has been preserved and used for artificial inseminations. captive lycaon pictus generally reproduce in the fall in the northern hemisphere. estrus lasts - days and includes vulvar swelling and sanguineous discharge with interest from the male. attraction from the male may be observed for - weeks prior to tying. , males show increased testicular development, spermatorrhea, and semen production; therefore the corresponding seasonal ability to collect sperm via electroejaculation is improved. the progestin-based melengestrol acetate (mga) implant, previously used in canids, has been associated with uterine pathology. the aza reproduction management center (formerly the wildlife contraception center) (www.stlzoo.org/ animals/scienceresearch/reproductivemanagementcenter) recommends gonadotropin releasing hormone (gnrh) agonists such as suprelorin (deslorelin acetate) implants or lupron depot (leuprolide acetate . mg implant, virbac extinction events. [ ] [ ] [ ] [ ] there is serologic evidence of exposure to canine parvovirus, canine distemper virus, adenovirus, rabies virus, coronavirus, rotavirus, and ehrlichia canis. , , outbreaks of anthrax in kruger national park occur, but infected animals commonly survive. contact with domestic dogs has been reported to increase exposure to some canid pathogens, but sylvatic viral strains also pose a significant threat. , parasitic disease and infection has rarely been described. [ ] [ ] [ ] toxocara canis, dipylidium caninum, spirometra sp., taeniidae, and ancylostoma spp., as well as two genera of canid protozoan gastrointestinal parasites, sarcocystis and isopora, were identified in fecal samples from free-ranging animals but were not associated with clinical disease. , standard anthelmintics at canine dosages have been successfully used to treat internal parasites. it is recommended that african wild dogs be routinely tested and maintained on prophylactic heartworm preventative in endemic areas. over the last decade, valvular dysplasia of varying severity has been increasingly recognized as a significant concern in african wild dogs in north america. sibling groups and offspring have been affected over multiple generations, and . show normal hematologic and serum chemistry reference ranges for captive african wild dogs. , diseases rabies and distemper have contributed to mortality in african dog populations, occasionally resulting in local neoplasia has not been extensively reported in the literature but appears to play an important role in the health of captive populations. apocrine gland tumors have been documented in clinical settings, presenting as single or multiple dorsal cutaneous masses that can progress to large regionally invasive tumors (fig. . ) (agnew, personal communication, april , ) . cases from females are overrepresented in pathology reports submitted to the african wild dog ssp (kinsel, personal communication, april , ). surgical excision is recommended, although large tumors may require other forms of treatment. tumor growth results in ulceration and necrosis and negatively affects an animal's quality of life. other common neoplasias include hemangiosarcoma, peripheral odontogenic fibroma (fibromatous epulis), adrenocortical adenoma/carcinoma, and mammary and uterine neoplasia. other notable conditions diagnosed in african wild dogs include dental disease-particularly fractured teethpancreatitis, diabetes, spina bifida, syringomyelia, keratitis, snake bites, and trauma from conspecifics (kinsel, personal communication, april , ). african wild dogs mask signs of illness and may have advanced disease by the time a change in behavior or appetite is observed. suggesting that the condition has a genetic, inheritable basis, as is well documented in domestic dogs. cases range from minor to severe valvular insufficiency with congestive heart failure (fig. . ) . mildly affected animals exhibit no clinical signs, making the condition difficult to detect. the extent of this disease is uncertain, but it is highly probable that cardiac disease is underdiagnosed. incorporating preventative health, preshipment, and quarantine examinations should be conducted to determine an animal's health. a complete physical exam-including a dental examination, complete blood count, chemistry panel, heartworm testing, urinalysis, radiographs of the thorax and abdomen, and evaluation for endo-and ectoparasites-should be completed on a routine schedule as part of a preventive medicine plan. additionally, abdominal ultrasound examination or computed tomography in females and echocardiograms for both sexes are recommended owing to disease predilection in this species. athens, georgia) provided persistent protective titers. a survey in showed that most african wild dogs maintained presumably protective titers after vaccination for canine distemper and rabies for year; however, few dogs maintained titers for - years. there is a paucity of scientific information regarding vaccination against canine parvovirus and leptospiral infection. protocols should be developed that take into consideration local environmental disease prevalence, animal health, and risk factors. select vaccination protocols for captive african wild dogs are listed in table . (see also chapter ). external and internal parasites should be treated according to domestic dog guidelines. fleas, ticks, and ear tip trauma from biting flies have responded well to products containing carbaryl or pyrethrins. good hygiene, removing standing water, fly traps, and premise sprays help control fly and mosquito populations. newly acquired animals should be quarantined away from the collection for a predetermined period based on a thorough risk assessment by the supervising veterinarian and have at least two negative fecal examinations. animals should be individually identified with microchip transponders placed subcutaneously between the shoulder blades or to the left of midline over the shoulder. currently there are no universal recommendations for vaccination protocols. the safety and efficacy of vaccines in african wild dogs have historically been unsatisfactory. vaccination strategies to conserve free-ranging populations have been reported and continue to be investigated. modified live canine distemper vaccinations have failed to produce protective antibody levels in some cases and have induced distemper resulting in mortality in other cases. , , , vaccine-induced distemper can be avoided by using killed vaccines, and at least one vaccine (purevax ferret distemper, merial inc., athens, georgia) has been shown to produce measurable titers after a series of three injections at -to -week intervals. subunit canine distemper vaccines (cdv-iscom, erasmus mc, rotterdam, the netherlands) stimulated appropriate titer formation, but titers did not endure relative to the purevax ferret distemper vaccine. vaccine recommendations for domestic dogs have been reduced from yearly to triennially; however, it is unknown whether nondomestic canids maintain titers in a similar manner. in one study, protective titers from the purevax vaccine persisted in %- % of african wild dogs for a minimum of year. early studies have indicated that vaccination with killed rabies vaccines may not be sufficient for protection. , , however, a recent study showed that a single intramuscular vaccination of dogs older than weeks with imrab (merial inc., the african wild dog: behavior, ecology and conservation canids: foxes, wolves, jackals and dogs. status survey and conservation action plan. iucn/ssc canid specialist group carnivora. in grzimek's animal life encyclopedia lycaon pictus (north africa subpopulation) birth order, estrogens and sex-ratio adaptation in african wild dogs (lycaon pictus) steroid metabolism and validation of noninvasive endocrine monitoring in the african wild dog (lycaon pictus) seasonal changes in steroid hormone profiles, body weight, semen quality and the reproductive tract in captive african wild dogs (lycaon pictus) in south africa naturally occurring and melengestrol acetate-associated reproductive tract lesions in zoo canids retrospective study of mortality of captive african wild dogs (lycaon pictus) in a french zoo cystic endometrial hyperplasia and pyometra in three captive african hunting dogs (lycaon pictus) control of reproduction and sex related behaviour in exotic wild carnivores with the gnrh analogue deslorelin: preliminary observations induction of contraception in some african wild carnivores by downregulation of lh and fsh secretion using the gnrh analogue deslorelin immobilization of wild dogs (lycaon pictus) with a tiletamine hydrochloride/ zolazepam hydrochloride combination and subsequent evaluation of selected blood chemistry parameters anesthesia of captive african wild dogs (lycaon pictus) using a medetomidine-ketamineatropine combination zoo animal and wildlife immobilization and anesthesia chemical restraint and immobilization of wild canids immobilization of freeranging african wild dogs (lycaon pictus) using a ketamine/ xylazine/atropine combination lycaon pictus, no selection by gender, all ages combined, cd.html in isis physiological reference intervals for captive wildlife: a cd-rom resource african wild dogs (lycaon pictus) endangered by a canine distemper epizootic among domestic dogs near the masai mara national reserve canine distemperrelated mortality among wild dogs (lycaon pictus) in chobe national park fatal canine distemper infection in a pack of african wild dogs in the serengeti ecosystem contact with domestic dogs increases pathogen exposure in endangered african wild dogs (lycaon pictus) diet of four sympatric carnivores in save valley conservancy, zimbabwe: implications for conservation of the african wild dog (lycaon pictus) aza canid tag: large canid (canidae) care manual population analysis and breeding and transfer plan: african painted (wild) dog (lycaon pictus) aza species survival plan yellow program general zims database reference: species , zims.species . org behavioural cues can be used to predict the outcome of artificial pack formation in african wild dogs (lycaon pictus) monitoring stress in captive and free-ranging african wild dogs (lycaon pictus) using faecal glucocorticoid metabolites evaluating adrenal activity in african wild dogs (lycaon pictus) by fecal corticosteroid analysis social stress and dominance reproductive hormonal patterns in pregnant, pseudopregnant and acyclic captive african wild dogs (lycaon pictus) studies of male reproduction in captive african wild dogs (lycaon pictus) enrichment options for african painted dogs (lycaon pictus) order carnivora hormonal and experiential factors in the expression of social and parenteral behavior of canids natural selection of the communal rearing of pups in african wild dogs (lycaon pictus) a molecular genetic analysis of social structure, dispersal, and interpack relations of the african wild dog (lycaon pictus) serosurvey for selected viral diseases and demography of african wild dogs in tanzania conservation role of captive african wild dogs (lycaon pictus) intrapartum uterine rupture with coincidental uterine adenomyosis in an african wild dog (lycaon pictus) vaccination strategies to conserve the endangered african wild dog (lycaon pictus) serum antibody levels before and after administration of live canine distemper vaccine to the wild dog (lycaon pictus) canine distemper in african hunting dogs (lycaon pictus) -possibly vaccine induced vaccine-associated canine distemper infection in a litter of african hunting dogs (lycaon pictus) comparison of oral and intramuscular recombinant canine distemper vaccination in african wild dogs (lycaon pictus) humoral immune response of african wild dogs (lycaon pictus) to novel canine distemper vaccines in proceedings of the attempts to reintroduce african wild dogs (lycaon pictus) into etosha national park, namibia single versus double dose rabies vaccination in captive african wild dogs (lycaon pictus) immunization and antibody persistence to canine distemper and rabies vaccination in captive african wild dogs (lycaon pictus rabies in african wild dogs (lycaon pictus) in the serengeti region serologic survey for selected microbial pathogens in african wild dogs (lycaon pictus) and sympatric domestic dogs (canis familiaris) in maasai mara an investigation into the health status and diseases of wild dogs (lycaon pictus) in kruger national park a survey of internal parasites in free-ranging african wild dogs (lycaon pictus distemperlike disease and encephalitozoonosis in wild dogs (lycaon pictus) molecular detection of babesia rossi and hepatozoon sp. in african wild dogs (lycaon pictus) in south africa african wild dog (lycaon pictus) and spotted hyaena (crocuta crocuta) in the luangwa valley, zambia multilobular tumor of bone in an african wild dog (lycaon pictus) successful snakebite treatment in three juvenile african wild dogs (lycaon pictus) with polyvalent antivenom: a namibian case report this chapter is dedicated to the researchers, veterinarians, biologists, and animal care staff that have contributed to our collective knowledge, helped conserve wild populations, and have improved the care of african wild dogs around the world. we thank drs. anneke moresco and mike kinsel for their contributions to reproduction, pathology, and disease presented in this chapter and drs. sathya chinnadurai and matthew lenyo for sharing their expertise and thoughtful review. key: cord- -arjzx c authors: ibrahimi, sahra; yusuf, korede k.; dongarwar, deepa; maiyegun, sitratullah olawunmi; ikedionwu, chioma; salihu, hamisu m. title: covid- devastation of african american families: impact on mental health and the consequence of systemic racism date: - - journal: int j mch aids doi: . /ijma. sha: doc_id: cord_uid: arjzx c african americans are bearing a disproportionate burden of morbidity and mortality due to covid- pandemic. to our knowledge, no previous study has delineated inequities potentially incentivized by systemic racism, and whether synergistic effects impose an abnormally high burden of social determinants of mental health on african american families in the era of covid- pandemic. we applied the social ecological model (sem) to portray inequities induced by systemic racism that impact the mental health of african american families. in our model, we identified systemic racism to be the primary operator of mental health disparity, which disproportionately affects african american families at all levels of the sem. programs tailored towards reducing the disproportionate detrimental effects of covid- on the mental health of african americans need to be culturally appropriate and consider the nuances of systemic racism, discrimination, and other institutionalized biases. covid- pandemic has further unveiled the distressful reality of racial disparity in the united states. african americans are bearing a disproportionate burden of morbidity and mortality due to covid- . in many cities like chicago, although african americans are only % of the population, they make up more than % of covid- cases and about % of covid- deaths. covid- health and economic consequences have a detrimental effect on mental health, particularly among african americans. according to kaiser health news report, compared with the rest of the population, african american adults are % more likely to experience mental health issues. systemic racism exacerbates the adverse impacts of social determinants of health, causing racial health disparities in african americans. african americans are more susceptible to contract covid- due to systemic racism that historically carved out the type of work they are obliged to perform including deliberate neighborhood and school segregation policies which currently explain their increased work place and environmental exposure to covid- infection. as a result, a greater proportion of african americans now suffer from the stress, anxiety and depression engendered by covid- . no previous study has delineated inequities incentivized by systemic racism, and whether synergistic effects impose an abnormally high burden of social determinants of mental health on african american families in the era of covid- pandemic. in this study, we hypothesized systemic racism to be the primary operator of the mental health disparity, which disproportionately affects the psychological well-being of african american families at all levels of the socio-ecological model (sem). a rapid search of the literature on covid- pandemic, the social determinants of mental health, systemic racism, as well as their impact on the mental health of african american families was conducted in pubmed and google scholar. next, the sem was employed to portray inequities induced by systemic racism, which aggravates the adverse effect of social determinants of mental health on african american families. the sem considers the complex interplay across individual, interpersonal, organizational, community, and public policy level factors. the model emphasizes that behaviors and the social environment have a symbiotic relationship and impact each other. the rapid search yielded research articles and only seven of them were included in this review. we found that covid- disproportionately impacts african american families and their mental health due to systemic racism, which intensifies the adverse effects of the social determinants of mental health. figure represents a social ecological model that delineates social determinants of mental health aggravated by systemic racism among african american families in the era of covid- pandemic. from the sem we found that at the individual level, african americans may experience stress from perceived knowledge of covid- that may be inaccurate and may stem from biased information presented by the local media and other social media networks. misinformation and more than conspiracy theories have been trending since the beginning of the pandemic and have led to confusion and stress. misinformation is more likely to trend among communities with limited access to quality educational resources. studies show that majority of african americans are systemically disadvantaged from proper education, distinctly afforded by asians and whites. therefore, misinformation may be more likely to prey on african americans than caucasians. at the interpersonal level, heightened stress and fear may also originate from family members and relatives whose lives and jobs are affected by covid- . because black families have been impacted disproportionally, they likely experience more stress than whites. according to the centers for disease control and prevention (cdc), african americans are less than % of the population but make up . % of hospitalized covid- patients. at the organizational level, african americans endure discrimination and racism at school and or work, while at the community level, african americans lack access to equitable mental healthcare, healthy food options, and recreational facilities. covid- health problems in the african american community manifest not because african americans do not like to social distance or take care of themselves, but because resources are abominably inadequate in their neighborhood. finally, at the public policy level, african americans are disadvantaged by segregated housing and lack of access to equitable education and job opportunities. compared with caucasians, african americans are more likely to live in densely populated areas, increasing their potential contact. as the number of contacts increases, so does the anxiety of being exposed to covid- . in addition, african americans make up the majority of the "essential" workforce, including % of bus drivers, and % of food service workers. these structural conditions exacerbate the impact of covid- on mental health as consequences of stress, fear, anxiety, and despair, which in severe cases result in posttraumatic stress disorder (ptsd) and or depression. covid- has impacted african american lives, including their mental health, at a higher rate compared to other racial/ethnic groups. as we had hypothesized, we found systemic racism to be the primary operator of the mental health disparity, which disproportionately affects the mental health of african american families at all levels of the sem. as a result of systemic racism that affects african americans at different levels, the standard mental health promotion approaches may not work in this population. studies show that public policies and health interventions that are tailored and adapted for local contexts and community characteristics are more beneficial and effective than standard approaches. programs tailored towards improving the mental health of african americans should be culturally appropriate and community competent. they also need to consider the nuances of systemic racism, discrimination, and other institutionalized biases at each level of the sem in order to reduce the disproportionate detrimental effects of covid- on the mental health of african americans. more importantly, policymakers and program implementers need to develop laws and programs that would dismantle systemic racism. public policies have the power to mitigate the impact of covid- among african americans and improve their mental health outcomes or to exacerbate health disparities. interpersonal level (il): stress from family members and relaƟves whose lives and jobs may be affected by covid- . stress from perceived knowledge that may be inaccurate and/or bias informaƟon on media and other social media networks. • african americans are bearing a disproportionate burden of morbidity and mortality due to covid- pandemic. • systemic racism is the primary operator of mental health disparity, which disproportionately affects african american families at all levels of the social ecological model (sem). • programs tailored towards reducing the disproportionate detrimental effects of covid- on the mental health of african americans need to be culturally appropriate and consider the nuances of systemic racism, discrimination, and other institutionalized biases. hospitalization rates and characteristics of patients hospitalized with laboratory-confirmed coronavirus disease -covid-net, states the covid- pandemic and mental health impacts black history month and african american mental health statistics alliance for science. covid: top current conspiracy theories why are blacks dying at higher rates from covid- ? key: cord- - z f gz authors: barreiro, luis b.; patin, etienne; neyrolles, olivier; cann, howard m.; gicquel, brigitte; quintana-murci, lluís title: the heritage of pathogen pressures and ancient demography in the human innate-immunity cd /cd l region date: - - journal: the american journal of human genetics doi: . / sha: doc_id: cord_uid: z f gz the innate immunity system constitutes the first line of host defense against pathogens. two closely related innate immunity genes, cd and cd l, are particularly interesting because they directly recognize a plethora of pathogens, including bacteria, viruses, and parasites. both genes, which result from an ancient duplication, possess a neck region, made up of seven repeats of amino acids each, known to play a major role in the pathogen-binding properties of these proteins. to explore the extent to which pathogens have exerted selective pressures on these innate immunity genes, we resequenced them in a group of samples from sub-saharan africa, europe, and east asia. moreover, variation in the number of repeats of the neck region was defined in the entire human genome diversity panel for both genes. our results, which are based on diversity levels, neutrality tests, population genetic distances, and neck-region length variation, provide genetic evidence that cd has been under a strong selective constraint that prevents accumulation of any amino acid changes, whereas cd l variability has most likely been shaped by the action of balancing selection in non-african populations. in addition, our data point to the neck region as the functional target of such selective pressures: cd presents a constant size in the neck region populationwide, whereas cd l presents an excess of length variation, particularly in non-african populations. an additional interesting observation came from the coalescent-based cd gene tree, whose binary topology and time depth (∼ . million years ago) are compatible with an ancestral population structure in africa. altogether, our study has revealed that even a short segment of the human genome can uncover an extraordinarily complex evolutionary history, including different pathogen pressures on host genes as well as traces of admixture among archaic hominid populations. infectious diseases have been paramount among the threats to health and survival for most of human evolutionary history (haldane ; lederberg ; harpending and rogers ; cooke and hill ) . the interaction of the human host with a wide variety of pathogens has been accompanied by genetic adaptations to spatially and temporally fluctuating selective pressures imposed by the infectious agents. numerous studies have sought the genetic imprint of natural selection imposed by pathogen pressures in human genes involved in immune response or, more generally, in host-pathogen interactions (vallender and lahn ) . for example, natural selection has acted on such genes as mhc, b-globin, g pd, il- , il- , tnfsf , the duffy blood group genes, and ccr (ohta ; hughes et al. ; flint et al. ; hamblin and di rienzo ; tishkoff et al. ; bamshad et al. ; sabeti et al. ; verrelli et al. ) . however, little is known about genetic variation of genes involved in direct recognition of pathogens, or pathogens' products, and virtually no studies have investigated the extent to which pathogens have exerted selective pressures on the innate immune system. the phylogenetically ancient innate immune system governs the initial detection of pathogens and stimulates the first line of host defense (medzhitov and janeway a janeway and medzhitov ) . recognition of pathogens is mediated by phagocytic cells through germline-encoded receptors, known as "pattern recognition receptors," which detect pathogenassociated molecular patterns that are characteristic products of microbial physiology (kimbrell and beutler ; janeway and medzhitov ) . this initial interaction is then translated into a set of endogenous signals that ultimately lead to the induction of the adaptive immune response (medzhitov and janeway b) . in recent years, the c-type lectin receptors have re- scaled diagram of the cd /cd l genomic region. sequenced regions are represented in gray. for cd , we sequenced a total of , bp per chromosome, and, for cd l, , bp per chromosome. the neck region corresponding to exon and composed of seven coding repeats is also shown. ceived much attention in the area of innate immunology, the results of which were novel functional insights into the primary interface between host and pathogens (medzhitov ; cook et al. ; fujita et al. ; geijtenbeek et al. ; mcgreal et al. ) . in this context, two prototypic members of the c-type lectinreceptor family are particularly interesting, since they can act as both cell-adhesion receptors and pathogenrecognition receptors. these lectins include cd (dc-sign: dendritic cell-specific icam- grabbing nonintegrin [mim ]) and its close relative cd l (l-sign: liver/lymph node-specific icam- grabbing nonintegrin [mim ]) (curtis et al. ; geijtenbeek et al. b geijtenbeek et al. , soilleux et al. ; pohlmann et al. ). these lectin-coding genes are located on chromosome p . - , within an ∼ -kb segment, and result from a duplication of an ancestral gene (bashirova et al. ; soilleux ). an additional characteristic of both cd and cd l is the presence of a neck region, primarily made up of seven highly conserved -aa repeats, that separates the carbohydrate-recognition domain involved in pathogen binding from the transmembrane region. this neck region presents high nucleotide identity between repeats, both within each molecule and between cd and cd l. it has been shown that this region plays a crucial role in the oligomerization and support of the carbohydraterecognition domain; therefore, it influences the pathogen-binding properties of these two receptors (soilleux et al. (soilleux et al. , feinberg et al. ) . in regard to expression profiles, cd is expressed primarily on phagocytic cells, such as dendritic cells and macrophages, whereas cd l expression is restricted to endothelial cells in liver and lymph nodes (bashirova et al. ; soilleux et al. soilleux et al. , . as pathogen-recognition receptors, the two lectins have been shown to recognize a vast range of microbes, some of which are of major public health importance (geijtenbeek et al. ) . indeed, cd captures bacteria such as mycobacterium tuberculosis, helicobacter pylori, and certain klebsiela pneumonia strains; viruses such as hiv- , ebola virus, cytomegalovirus, hepatitis c virus, dengue virus, and sars-coronavirus; and parasites like leish-mania pifanoi and schistosoma mansoni (geijtenbeek et al. a alvarez et al. ; colmenares et al. ; halary et al. ; appelmelk et al. ; lozach et al. ; tailleux et al. ; tassaneetrithep et al. ; bergman et al. ; marzi et al. ) . with regard to cd l, studies to date have shown an interaction with a variety of viruses, including hiv, hepatitis c, ebola, and coronavirus, as well as with the parasite schistosoma mansoni (bashirova et al. ; alvarez et al. ; gardner et al. ; jeffers et al. ; van liempt et al. ) . in this context, the efficiency of the two lectins in pathogen recognition and subsequent processing may have important consequences for the quality of host immune responses and consequent pathogen control and/or clearance. an important step forward in the understanding of human adaptation to pathogens and control of infectious diseases includes the description of quality and quantity of genetic variation in genes involved in host recognition of infectious agents. given the direct interaction of cd and cd l with a large variety of pathogens, the cd /cd l genomic region provides an excellent model system to illustrate the extent to which pathogens have exerted selective pressures on host immunity genes. an additional feature that makes these genes highly interesting in evolutionary studies is that they are likely to have been influenced by similar genomic forces (recombination, mutation rates, etc.) because of their close physical proximity (∼ kb), high nucleotide ( %) and amino acid ( %) identity, and identical exon-intron organization (soilleux ) ). in addition, it has been proposed that gene duplication of immunity genes is a molecular strategy developed by the host to enlarge its defense potential (ohno ; trowsdale and parham ) . a number of immune-system gene families have evolved, by gene duplication followed by natural selection, to provide responses to a wider range of pathogens, with welldocumented examples in immunoglobulin and mhc genes (hughes et al. ; ota et al. ) . in this context, duplicated genes in cis, like cd and cd l, may have undergone differential selective pressures to enlarge the defense role of these lectins. to address these complex issues, we performed a sequence-based survey of the entire cd /cd l region in a panel of individuals of different ethnic origins. here, we report evidence showing that these two closely related innate immunity genes have gone through completely different evolutionary processes that are reflected in their current patterns of diversity. in addition, our study provides novel insights into how pathogens have shaped the patterns of variability of immunity genes resulting from gene duplication. sequence variation of the cd /cd l region was determined in sub-saharan africans, europeans, and east asians, in a total of chromosomes from the human genome diversity panel (hgdp)-ceph panel ). more-detailed information about the composition of the three major ethnic groups can be found in table . the variation in the repeat number of the neck region of cd and cd l was defined in the entire hgdp-ceph panel, comprising , dna samples from worldwide populations. in addition, the orthologous regions for both genes were sequenced in four chimpanzees (pan troglodytes). the sequenced fragments of the cd /cd l genomic region are shown in figure . the entire cd region-including exons, introns, and ∼ kb of the utr corresponding to the promoter region-was sequenced, for a total of . kb per individual. for cd l, we sequenced a total of ∼ . kb per individual, following the same approach used for cd , with the exception of the neck region. that region was genotyped for its number of repeats, since it turned out to be highly polymorphic, which prevented the sequencing process. genotyping was performed by a single pcr amplification followed by migration in % agarose gels. human primers were used to both amplify and sequence the orthologous regions in chimpanzees. however, because of polymorphisms specific to the chimpanzee lineage, we could not obtain the entirety of the sequence. thus, . kb ( % of the total) of the chimpanzee cd sequence were obtained, and . kb ( % of the total) of cd l. detailed information on primer sequences and pcr amplification conditions is available on request. all nucleotide sequences were obtained using the big dye terminator kit and the automated sequencer from applied biosystems. sequence files and chromatograms were inspected using the genalys software (takahashi et al. ; centre national de genotypage). as a measure of quality control, when new mutations were identified in primer binding regions, new primers were designed and sequence reactions were repeated, to avoid allele-specific amplification. all singletons observed in our data set were systematically reamplified and resequenced. on the basis of the levels of diversity observed in the cd /cd l genomic region, we calculated the average number of pairwise differences (p) and the watterson's estimator ( ) (watterson (fay and wu ) . p values for the different tests were estimated from coalescent simulations under an infinite-site model, with use of a fixed number of segregating sites and the assumption of no recombination, which has been shown to be a conservative assumption (gilad et al. ) . in parallel, we estimated p values for all these tests, using the empirical distribution obtained from sequencing data of genes in a panel of african americans and european americans (akey et al. ). all these analyses, together with the interspecies mcdonald-kreitman (mcdonald and kreitman ) and k a /k s (kimura ) tests, were performed using the dnasp package (rozas et al. ) . genetic distances between populations (f st ) and heterozygosity values were estimated using the arlequin package (schneider et al. ) . f st statistical significance was assessed using , bootstrap replications. to bear out a deficit or an excess of heterozygosity in the neck region of cd and cd l, we used bottleneck (cornuet and luikart ) to compute for each geographic region, the distribution of the heterozygosity expected from the observed number of alleles, given the sample size (n) under the assumption of mutational-drift equilibrium. this distribution was obtained through simulation of the coalescent process of n genes under two mutational models, the infinite-site model and the stepwise mutation model. in addition, to obtain information on the fraction of genetic variance in the neck region that is due to intraand interpopulation differences, we performed an anal-ysis of molecular variance (amova), using the arlequin package (schneider et al. ) . the amova results were compared with those of microsatellites analyzed in the same population panel . haplotype reconstruction was performed by use of the bayesian statistical method implemented in phase (v. . . ) (stephens and donnelly ) . we applied the algorithm five times, using different randomly generated seeds, and consistent results were obtained across runs. after haplotype reconstruction, linkage disequilibrium (ld) between pairs of snps was computed using lewontin's d index (lewontin ) . for this analysis, only markers presenting a minimum allele frequency (maf) of % were considered, since rare alleles have been shown to present a higher probability of being in significant ld than do common ones (reich et al. ) . the graphic display of the ld plots was constructed using gold (abecasis and cookson ; center for statistical genetics) . to support the existence of a recombination hotspot in the region under study, we used the hotspot-recombination model implemented in phase (v. . . ). under this model, we assumed that there was, at most, one hotspot of unknown position. we then estimated the background population-recombination rate (r) and the relative intensity of any recombination hotspot. to obtain better estimates, we increased times the number of iterations of the final run of the algorithm. all our estimations were obtained by averaging results of five independent runs with use of different seed numbers. since the model used is bayesian, we could also estimate, for each population, the posterior probability of a hotspot of intensity ( ) l and ( ). l we obtained the gene tree and estimated the time of the most recent common ancestor (t mrca ) for cd , using the maximum-likelihood coalescent method implemented in genetree (griffiths and tavare ) . the mutation rate m for each gene was estimated on the basis of the net divergence between humans and chimpanzees and under the assumption both that the species separation occurred million years ago (mya) and of a generation time of years. using this m and v maximum likelihood (v ml ), we estimated the effective population size parameter ( ). with the assumption of a n e generation time of years and the estimated , the n e coalescence time, scaled in units, was converted into n e years. the coalescence process implemented in sim-coal (laval and excoffier ) allowed us to estimate the probability of the t mrca for cd , through simulations, with use of both the number of # observed segregating sites and the estimated . n e we determined sequence diversity in the cd and cd l genes ( fig. ) as well as length variation of the neck region in chromosomes originating from three major ethnic groups: sub-saharan africans, europeans, and east asians. in addition, the orthologous sequences were obtained in four chimpanzees, to infer the ancestral state at each site, to estimate the divergence between humans and chimpanzees, and to perform a number of interspecies neutrality tests. for cd , we identified a total of snps and indels, including nonsynonymous, synonymous, and noncoding variants. the five nonsynonymous snps were all located in the neck region (exon ): snps (argrgln), (glurasp), and (argrgln) achieved a frequency of ∼ %, and snp (leur val), a frequency of %. these mutations were restricted to the african sample. snp (alarthr) was observed as a singleton in an east-asian individual. for cd l, we identified snps and indels, including nonsynonymous and noncoding variants. the four nonsynonymous variants were located in different exons: snp (thrrala) in exon , snp (aspr asn) in exon , snp (thrrala) in exon , and snp (argrgln) in exon . all these mutations were singletons except snp , which presented high frequencies for its derived allele in all geographic regions: . % in africans, % in europeans, and % in east asians. all variable sites were in hardy-weinberg equilibrium for both cd and cd l, after bonferroni correction for multiple testing. the allelic composition of cd and cd l haplotypes and their frequency distribution in the three major ethnic groups is illustrated in figure , along with the haplotype composed of the ancestral allelic state of each snp inferred from chimpanzee data. for cd , we identified different haplotypes, with an overall heterozygosity of % (table ) . three major haplotypes (h , h , and h ) accounted for ∼ % of the african variability, whereas they were at very low frequency (h at ∼ %) or absent (h and h ) in europeans and east asians ( fig. a ). in turn, the two haplotypes (h and h ) that accounted for % and % of the european and east asian variability, respectively, were observed at very low frequency (h at %) or even absent (h ) in africa. however, h , which had a frequency of % and % in europe and east asia, respectively, is just a one-step mutation (snp ) from h , the most frequent haplotype in the african sample. the most in- inferred haplotypes for cd (a) and cd l (b). the chimpanzee sequence was used to deduce the ancestral state at each position, except for the cd l positions , , and . for those polymorphisms, the ancestral state was considered to be the most frequent allele. dark boxes correspond to the derived state at each position. the numbers on the right of the figure indicate the absolute frequency of each haplotype in the different populations studied. repeat-number variation in the neck region of each gene is reported in the gray columns with the column heads "nr." indel polymorphisms are referred as to " " for insertion and " " for deletion. teresting observation of the cd haplotype variability was the presence of a highly divergent haplotype cluster. this cluster, which contains haplotypes - (referred to here as "cluster a"), differs from all other haplotypes (referred to here as "cluster b") by fixed positions ( fig. a ). cluster a is africa specific and is present at a frequency of ∼ %, whereas cluster b is present in the remaining african and all non-african samples. it is worth noting that three (snps (snps , (snps , and of the five nonsynonymous mutations identified for this gene are unique to cluster a. in all cases, these three mutations were segregating together, with the exception of one haplotype, h , which does not contain the snp . samples from cluster a are geographically wide- b) , with an overall heterozygosity of % (table ) . only one haplotype (h ) at a frequency of ∼ % was shared in the three continental regions. to assess the degree of population differentiation, if any, we computed wright's f st (wright ) , using haplotype frequencies. estimates were significant f st ( ) for all population comparisons, indicating p ! . continental differentiation for both cd and cd l. however, substantial differences were observed between the two genes: the overall f st for cd among africans, europeans, and east-asians was . , whereas cd l presented a threefold lower f st value of . . for both genes, the larger f st values were observed between african and east asian populations, with f st values of . for cd and . for cd l. the average nucleotide diversity (p) was strikingly different, both between the two genes and among populations (table ) . globally, p values were three-to fivefold lower for cd ( ) than for cd l Ϫ - # (∼ # Ϫ ), except for african populations, for whom the cd p value was unusually high ( ) be-Ϫ # cause of the presence of the highly divergent cluster a. indeed, when cluster a was excluded from the analysis, the african p value dropped to . to estimate Ϫ # the substitution rate of each region and evince possible mutational differences that could explain the strong contrast observed in nucleotide-diversity patterns, we determined the human-chimpanzee divergence for both genes. the average net number of differences between the two species was . substitutions (or . substitutions per nucleotide) for cd and . substitutions (or . substitutions per nucleotide) for cd l. since the human-chimpanzee speciation occurred mya, we obtained similar nucleotide-substitution rates per site per year (cd , ; Ϫ . # cd l, ). Ϫ . # to assess the patterns of ld in the cd /cd l region, haplotypes for the entire genomic region were reconstructed using markers with an maf of %. d measures among these markers were estimated for african and non-african populations independently; the graphical representation of ld levels is illustrated in figure . two distinct regions, which correspond to either cd or cd l, showed strong ld and are separated by a boundary that corresponds to the intergenic region. for cd , a block of intragenic ld was observed in both african and non-african populations. for the african sample, % of all pairwise comparisons indicated significant levels of ld, whereas, for non-africans, all d pairwise comparisons were significant. the magnitude of intragenic recombination (and/or gene conversion) of cd l was slightly higher than for cd . nevertheless, considerable and significant levels of ld were observed between sites: % of all ld pairwise comparisons were significant in the african group, and % were in the non-african sample. overall, cd exhibited a blocklike structure in both groups, whereas cd l presented lower-although mostly pairwise d ld plots in non-african and african populations. european and east asian samples were plotted together as "non-africans" because they showed similar levels of ld (data not shown). red tags indicate the physical position of each snp across the genomic region studied. blue and green lines label the snps ( ) used for cd and cd l, respectively, in the ld plot. for cd , maf % snps presented an in the african sample and in the non-african, whereas, for cd l, snps showed an in maf % maf % africans and in non-africans. the high prevalence of snps with for cd in africa is due to the presence of the highly maf % divergent cluster a, which presents diagnostic variants with a frequency of %. significant-ld levels, in particular among the non-african sample. the strong decay in ld observed in the intergenic region ( fig. ) , which spans only ∼ kb, suggests the occurrence of a number of recombination events. to test the hypothesis of a possible recombination hotspot situated within this region, recombination parameters across the entire cd /cd l region (∼ kb) were computed for the three populations, by use of the recombination model implemented in phase (v. . . ) ( fig. ). this model (stephens and donnelly ) estimates the position and relative intensity of the hotspot (l) as compared with the background population recombination rate (r) (see the "material and methods" section). a l value of corresponds to absence of recombinationrate variation, whereas l values indicate the presence of a hotspot. the model detected the occurrence of a hotspot in the intergenic region, with africans presenting a l of , whereas europeans and east asians exhibited l values of and , respectively ( fig. ) . we estimated the posterior probabilities of a hotspot of any kind, , and of at least times the background re-pr (l ) combination rate, . was % for pr (l ) pr (l ) all population groups, and was % for af-pr (l ) ricans, % for europeans, and % for east asians. thus, our data clearly indicate a relative increase of the recombination levels between the two genes, which suggests the occurrence of a hotspot of recombination, the magnitude of which varies among the major ethnic groups. however, our data do not include intergenic snps; therefore, the exact location and width of the recombination hotspot within the intergenic region remains unclear, since this observation would be consistent with either an intense narrow hotspot or a weaker but wider hotspot. the identification of a strong decay in ld between cd and cd l facilitated the interpretation of neutrality tests, because the noise introduced by hitchhiking effects between the genes is reduced. we applied tajima's d and fay and wu's h tests to determine whether these statistics significantly deviated from expectations under neutrality, using both coalescent simulations and the empirical distribution obtained from akey et al. ( ) . globally, tajima's d test indicated different tendencies for the two genes (table ) . cd always yielded negative values for tajima's d but never achieved significance to reject the hypothesis of neutrality, whereas cd l yielded significantly positive values for non-african populations, with use of both estimates of the hotspot intensity (l) for africans, europeans, and east asians. estimates of the population recombination rate (r) for each population as well as the posterior probabilities of and are also reported in the key. l l (table ) . to evaluate the selective pressures at the protein level, we performed two interspecies tests: k a /k s , which gives the ratio of nonsynonymous and synonymous changes between species, and the mcdonald-kreitman test, which tests the null hypothesis that the ratio of the number of fixed differences to polymorphisms is the same for both nonsynonymous and synonymous mutations. for the k a /k s test, cd and cd l showed similar values, . and . , respectively. for the mcdonald-kreitman test, the hypothesis of neutrality was rejected for only cd , because of a clear lack of nonsynonymous polymorphic sites (table ) . the identical genomic organization of cd and cd l is extended to the neck region, which, in both genes, encodes a track of seven coding repeats of aa each ( fig. ) (soilleux et al. ) . a previous study has shown that the length of the neck region of cd l varied between individuals of european descent (bashirova et al. ) . to investigate the degree of polymorphism of the neck region in both cd and cd l, we genotyped it in the entire hgdp-ceph panel ( , individuals from worldwide populations). striking differences were observed between the two genes (see fig. and table for detailed allele frequencies in each population). for cd , virtually no variation was observed, and the -repeat allele accounted for % of the total variability. despite this limited variation, eight different alleles were observed, with an allele size range of - repeats, not including a -repeat allele. the geographic region that presented the highest variability was the middle east, with five of the eight different alleles observed ( fig. a and table ) . for cd l, a com-pletely different pattern emerged, with strong variation in allelic frequencies of different repeat numbers. of the seven alleles observed (from - -repeat allele size classes), the three most common overall were the -( . %), the -( . %), and the -( . %) repeat alleles. european, asian, and pacific populations presented a mosaic composition of different allelic classes, whereas -and -repeat alleles accounted for most ( %) of the african diversity ( fig. b ). the strong difference in the neck-region lengths between the two genes was consequently visible in the heterozygosity values: cd exhibited an overall heterozygosity of only %, whereas cd l presented a value of % (table ) . our results showed that the levels of heterozygosity observed at cd were considerably lower than expected, regardless of the mutation model considered (i.e., infinite site or stepwise mutation models) (table ). in strong contrast, although not statistically significant for individual populations, cd l exhibited a pattern of an excess of heterozygosity in all populations. the table is available in its entirety in the online edition of the american journal of human genetics. the low levels of intragenic recombination observed in cd allowed maximum-likelihood coalescent analysis (griffiths and tavare ) for estimation of the time scale of the origin and evolution of this gene. since this method assumes an infinite-site model without recombination, the same analysis for cd l was not conducted because of the substantial amount of recombinant haplotypes observed. for cd , only of the chromosomes analyzed had to be excluded, as did a single segregating site (snp ). the resulting cd gene tree estimate, rooted with the chimpanzee sequence (i.e., the chimpanzee sequence was used to define ancestral/derived status of human mutations), is shown in figure . the tree is partitioned into two deep branches that correspond to haplotype clusters a and b. african samples were observed in both sides of the deepest node of the tree (i.e., in both clusters a and b), whereas non-african samples are restricted to one branch of the tree (i.e., cluster b). the maximum-likelihood estimate of v (v ml ) for cd was . . on the basis of this v ml value and the estimated mutation rate ( per gene Ϫ . # per generation), the effective population size ( ) was n e , , a value comparable to most figures reported in the literature (for a review, see tishkoff and verrelli [ ] ). the t mrca of the cd tree was then estimated at mya, one of the oldest t mrca val- . ‫ע‬ . ues estimated so far in the human genome (excoffier ). the cd /cd l region possesses a number of characteristics that make it a powerful tool for evolutionary inference. these two genes are not in ld, despite their very close physical vicinity (∼ kb), and each of them behaves as an independent genetic entity. moreover, our results suggest that the cd /cd l region is a uniform landscape of genomic forces, since the two lectincoding genes present similar mutation rates, as well as high nucleotide identity and conserved exon-intron organization ( fig. ). our diversity study revealed completely different patterns for the two genes. first, levels of nucleotide diversity (p) were found to be much lower for cd than for cd l (table ) . on the basis of . million snps, the international snp map working group defined as the average value of nucleotide di-Ϫ . # versity for the human genome and showed that % of all bins presented p values varying from to Ϫ . # (sachidanandam et al. ). in addition, Ϫ . # an independent study analyzed nucleotide and haplotype diversity for genes and defined the average p value as (stephens et al. ) . in this context, the ) are at least twofold higher than average Ϫ - # genome estimates and fall into the upper limit of the % ci defined by the snp consortium (sachidanandam et al. ) . this contrast in nucleotide diversity between the two genes can be explained either by a disparity in local mutation rates or by actual differences in selective pressures. however, no major differences in mutation rates ( vs. ) were ob- . # . # served between the two homologues, nor was there substantial variation in gc content, which has been positively correlated with mutation rates and levels of polymorphisms (sachidanandam et al. ; smith et al. ; waterston et al. ; hellmann et al. ) . indeed, the gc content for cd ( . %) was slightly higher than that observed for cd l ( . %), which reinforces the idea that different selective pressures may indeed have been the driving force behind the distinct patterns of diversity observed. second, the patterns of repeat variation in the neck region also turned out to be strikingly different between the two genes. cd showed levels of heterozygosity of only %, whereas cd l presented an extraordinarily high level of worldwide diversity, with an overall heterozygosity of % (table and fig. ). although the neck regions of both genes share % of nucleotide identity, nonuniform mutation rates could, again, explain the patterns observed. however, this does not seem to be the case, since mutation-rate variation should influence the number of alleles observed rather than their frequencies, which are subject either to genetic drift or to natural selection. indeed, we observed an even higher number of repeat alleles for cd (eight alleles) than for cd l (seven alleles) (table and fig. ). overall, differences in genomic forces seem to be insufficient to explain the contrasting patterns observed at both the sequence and neck-region length variation levels; therefore, the action of differential selective pressures acting on these genes becomes the most plausible scenario. for cd , not only nucleotide diversity but also f st intercontinental values ( . ) were in conformity with previous worldwide estimations (harpending and rogers ; akey et al. ; cavalli-sforza and feldman ) . for frequency-spectrum-based tests, only fay and wu's h test detected an excess of highly frequently derived alleles for the african and east asian samples, a picture that may be interpreted as the result of a selective sweep. however, the significantly negative value observed in africa is, again, exclusively due to the presence of cluster a, since of the fixed snps distinguishing it from cluster b corresponded to the derived allelic status in the latter cluster. because cluster b accounts for % of the african variability, a clear excess of frequently derived alleles was observed. the extent to which the presence of this cluster is due to either natural selection or population structure will be discussed in detail below. for east asia, the significance of the h test is also questionable when accounting for the confounding effects of demography. indeed, when we plotted our h value against the empirical distribution of h values from non-african populations (akey et al. ) , the east asian p value became nonsignificant ( ). this observation reinforces the idea that the p p . h test is particularly sensitive to past bottlenecks and/ or population subdivision (przeworski ) . thus, regarding the global levels of sequence diversity, the cd locus seems to evolve under evolutionary neutrality. nevertheless, when we focused our analyses at the protein level, signs of natural selection were uncovered. indeed, the mcdonald-kreitman test rejected neutrality for this gene because of a clear excess of polymorphic synonymous sites (i.e., a lack of nonsynonymous variants). in addition, when the number of synonymous sites ( ) versus nonsynonymous sites ( ) was compared with the observed number of synonymous ( ) versus nonsynonymous ( ) mutations, we detected a significant lack of nonsynonymous mutations (twotailed fisher exact test, ). these obser-Ϫ p p . # vations point to a strong selective constraint acting on cd that prevents the accumulation of amino acid replacements over time. further support for a functional constraint in cd comes from the patterns of diversity observed in the neck region. in contrast to cd l, virtually no variation was observed at cd ( fig. a) , with the -repeat allele accounting for % of the total variability. moreover, the low levels of heterozygosity observed resulted in a consistent rejection of mutation-drift equilibrium in almost all geographical regions (table ). the probability of finding such a low heterozygosity value, given the overall number of alleles observed, was estimated to be ! . %, independent of the mutational model considered (table ) . thus, the fact that no alleles other than the repeat allele have increased in frequency, together with recent studies addressing the functional consequences of a populations are grouped as described by rosenberg et al. ( ) . b amova values are from our cd l study; % cis are defined from autosomal microsatellites in the same population panel repeat-number variation in this region (bernhard et al. ; feinberg et al. ) , strongly suggests a clear reduced fitness of any allele other than the -repeat allele. interestingly, it has been recently shown that a protein with two fewer repeats (a -repeat allele) results in a partial dissociation of the final tetramer, whereas a protein with ! repeats exhibits a dramatic reduction in overall stability (feinberg et al. ) , with all these differences having a direct impact on the quality of ligand-binding functions (bernhard et al. ) . taken together, the patterns of diversity observed at cd clearly point to a strong functional constraint acting on this gene and further support the proposed crucial role of this lectin in pathogen recognition and in the early steps of immune response (geijtenbeek et al. b (geijtenbeek et al. , . in clear contrast to its homologue, cd l presented extremely elevated nucleotide-diversity levels. high levels of diversity can result either from a relaxation of the functional constraint, which allows the stochastic accumulation of new mutations, or from the action of balancing selection, which maintains over time two or more functionally different alleles (and all linked variation) at intermediate frequencies. several lines of evidence lend support to the selective hypothesis. first, if cd l nucleotide diversity has been driven by the action of balancing selection, population-genetics relationships would have been accordingly altered. in this context, diversity studies in neutral, or assumedly neutral, regions of the genome-such as the y chromosome (underhill et al. ; hammer et al. ; jobling and tyler-smith ) , mtdna (wallace et al. ; ingman et al. ; mishmar et al. ) , alu insertions (watkins et al. ) , as well as some autosomal genes (stephens et al. ; akey et al. )-showed that african populations are genetically more diverse than are non-africans, an observation generally interpreted as a support of the "out of africa" model for the origin of modern humans (lewin ) . for cd l, even if we observed . times more segregating sites in african than in non-african populations, as indicated by the higher value found in africa, similar values of nucleotide v w diversity were detected in the three groups, with europeans presenting even higher p values than do africans. this unusual scenario, which is at odds with neutral expectations, has already been described for other regions of the genome, such as the b-globin gene and the cis-regulatory region of ccr , for which the action of balancing selection has been convincingly proposed (harding et al. ; bamshad et al. ) . second, balancing selection tends to increase within-population diversity while decreasing f st , compared with neutrally evolving loci (cavalli-sforza ; harpending and rogers ; akey et al. ; bamshad and wooding ; cavalli-sforza and feldman ) . indeed, our data are compatible with these predictions, since the % f st value observed for cd l is threefold lower than that estimated for cd ( %) and is similar to that found, for example, for the bitter-taste receptor gene ( . %), for which there is compelling evidence of balancing-selection action (wooding et al. ) . third, results of our tajima's d analysis were significantly positive for european and east asian populations, because of the skew of cd l frequency spectrum toward an excess of intermediate-frequency alleles (table ), a pattern that further supports the action of balancing selection. however, since the null model used to assess significance makes unrealistic assumptions about past population demography (i.e., constant population sizes), the rejection of the standard neutral model cannot be interpreted as unambiguous evidence of selection. indeed, the observation that only non-african populations showed a significant departure from neutrality raises the question of whether these patterns could have resulted instead from the bottleneck that occurred during the out of africa exodus. a way to circumvent this conundrum is to analytically integrate the fact that demography affects all the genome equally, whereas selection directs its effects toward specific loci. thus, to correct for the confounding effects of demography, we plotted our results against the empirical distributions of akey et al. ( ) for tajima's d statistics. our values remained significant for cd l, which therefore reinforces the idea that the pattern observed is unlikely to be the sole result of demography. last, if the patterns of variation in cd l represent the molecular signature of balancing selection, at least in non-africans, then a functional target of such selective regime is needed. in this context, the neck region constitutes an excellent candidate, since it plays a major mediating role in the orientation and flexibility of the carbohydrate-recognition domain. since this domain is directly involved in pathogen recognition, neck-region length variation has important consequences for the pathogen-binding properties of these lectins (mitchell et al. ; bernhard et al. ; feinberg et al. ) . in perfect agreement with the results of our sequence-based data set, higher diversity in repeat variation was observed in the neck region among non-african populations (native americans excepted). out of africa, at least three alleles account for most population diversity, whereas, in africa, the -and -repeat alleles alone account for % of the global variability ( fig. b ). again, the higher diversity observed out of africa could be due to a higher level of relaxation of the functional constraint of the neck region in non-african compared with african populations, which would lead to a random accumulation of proteins with varying neck-region lengths among non-africans. conversely, these patterns could also be explained by the action of balancing selection in non-africans and could therefore point to the neck region as the functional target of such selective regime. to evaluate the plausibility of these two conflicting scenarios, we compared the variation in the cd l neck region with that inferred from neutral autosomal microsatellites typed elsewhere for the same population panel . we reasoned that if cd l diversity has been shaped only by demography (i.e., bottleneck out of africa), the distribution of genetic variance at different hierarchical levels should be comparable to that inferred through the neutral markers. on the other hand, if selection has driven the cd l neckregion diversity, population-genetics distances would be influenced accordingly and would therefore differ from neutral expectations. indeed, the amova values inferred for cd l fell systematically outside the % ci defined for the microsatellite data set (table ). we observed that populations within europe, asia, the middle east, and oceania exhibited lower-than-expected diversity among populations within the same region. a reduction of genetic distances between populations is expected under balancing selection; therefore, the results from the cd l neck region favor, once again, the action of this selective regime in most non-african populations, in detriment of the neutral hypothesis. one may argue that the differences in the proportions of genetic variance between our data and those of could be due to differences in the pace of mutation between microsatellite loci and our neck repeated region that could be considered a "coding minisatellite." however, under neutrality, differences in mutation rate should have a similar and proportional effect in all population comparisons and should influence all values with a similar tendency (i.e., higher or lower values). indeed, this is not the case: populations within europe, the middle east, central/south asia, east asia, and oceania turned out to be genetically closer than expected, whereas populations within africa and the americas exhibited the opposite pattern (table ) , which makes it highly unlikely that mutation-rate differences influenced our conclusions. taken together, the integration of the results from levels of nucleotide and amino acid diversity, neutrality tests, population-genetics distances, and neck-region length variation in cd and cd l clearly points to a situation in which cd has been under a strong selective constraint that prevents accumulation of any of amino acid changes over time, whereas cd l variability has most likely been driven by the action of balancing selection, at least in non-african populations. in apparent dichotomy with the strong selective constraint described for cd , we observed an unusual excess of diversity of fixed differences separating the two basal branches of the gene tree ( fig. ). in addition, we estimated a t mrca of mya, a time that . ‫ע‬ . places the most recent common ancestor of cd back in the pliocene epoch, before the estimated time for the origins of the genus homo ∼ . mya (wood ; wood and collard ) . a number of studies have already reported loci that present unusually deep coalescent times (harris and hey ; zhao et al. ; webster et al. ; garrigan et al. a garrigan et al. , b , but our estimation for cd remains one of the deepest t mrca values yet reported (excoffier ) . the probability of finding such a deep coalescence time under a scenario of a random-mating population was estimated, through a coalescent process (laval and excoffier ) , to be very low ( ) (see fig. ). in addition to the p p . unexpected antiquity of the cd locus, we observed a peculiar tree topology made of two highly divergent and frequency-unbalanced lineages, cluster a embracing only internal haplotypes and cluster b comprising the remaining ( fig. ). different hypotheses can account for such elongated and divergent haplotype patterns. indeed, the high levels of nucleotide identity between cd and cd l could have led to gene conversion between the two genes, an event that would explain the outlier position of cluster a in the context of cd phylogeny. we reasoned that if gene conversion has occurred, we expect that the derived alleles distinguishing clusters a and b in cd would correspond to the allelic state observed in their homologous positions in cd l. of all positions, only four fit this criterion. in addition, these positions were not physically clustered, which therefore excludes a major gene-conversion event as the explanation of the divergent cd phylogeny. two other circumstances may be responsible for the topology and the time depth of the cd gene tree: long-standing balancing selection or ancient population structure, with africa, in both cases, being the arena of such events (i.e., cluster a is restricted to africa). several lines of evidence argue against the balancing-selection hypothesis. first, under this selective regime, one would expect that tajima's d test would also point in this direction by yielding significantly positive values, which is not the case (table ) . second, such a long-standing balancing selection in africa would have entailed a number of recombinant haplotypes between clusters a and b, which, again, is not the case, as illustrated by the high ld levels at cd (fig. ) . third, a claim of balancing selection at this locus must imply a functional difference between the two balanced alleles. indeed, three nonsynonymous mutations, situated in the neck region, separate cluster a and b, and they could correspond to the alleles under selection. but, if the neck region is the target of selection, it is more likely that the balanced alleles would correspond to different numbers of repeats rather than punctual nucleotide variation within each track, as observed for cd l and suggested by functional studies (bernhard et al. ; feinberg et al. ) . since no variation in the number of repeats was detected between both clusters, we predict that there are no major functional differences between the two lineages. taken together, maintenance of ancient lineages by balancing selection does not seem to be responsible for the observed haplotype divergence. in this view, the patterns observed are best explained by an ancestral population structure on the african continent. indeed, several studies have already proposed that african populations must have been more strongly subdivided and isolated than non-african ones (harris and hey ; labuda et al. ; excoffier ; goldstein and chikhi ; harding and mcvean ; satta and takahata ; garrigan et al. a) . in particular, a recent study of the xp . locus presented convincing statistical evidence that supports the hypothesis that our species does not descend from a single, historically panmictic population (garrigan et al. a ). the divergent haplotype pattern observed at the xp . locus prompted those authors to explain their data under the isolation-and-admixture (iaa) model and/or a metapopulation model (harding and mcvean ; wakeley ) . indeed, as observed for cd , under an iaa model, the two basal branches are expected to be longer than those under a wright-fisher model, depending on the length of time subpopulations spent in isolation. the extent to which the iaa model fits the data depends on the number of mutations, referred as to "congruent sites," occurring in the two basal branches of the genealogy. for xp . , congruent sites over polymorphisms were observed (i.e., ∼ % of the total number of sites). we applied the same approach to cd and obtained a very similar percentage of ∼ %, in good accordance with the iaa model. our observations, together with a number of autosomal diversity studies, show that modern human diversity appears to have kept genetic traces of admixture among archaic hominid populations. however, a number of questions remain unanswered, such as the time when these admixture events occurred (i.e., before or after the appearance of anatomically modern humans), the precise quantitative contribution of ancient genetic material to our modern gene pool, and the geographic provenance of these genetic vestiges. the need of continuous evolution for both the human host and the pathogens is predicted by the red queen hypothesis (van valen ; bell ) , in reference to the remark of the red queen to alice in through the looking glass (carroll ) : "now, here, you see, it takes all the running you can do, to keep in the same place." this metaphor provides a conceptual framework for understanding how interactions between the two species lead to constant natural selection for adaptation and counteradaptation. in this context, one feature exploited by the host immunity genes to increase their defense potential is gene duplication by retention, through conservation of one duplicate, of the currently useful function of the encoded protein, while its twin is liberated to mutate and possibly acquire novel functions (ohno ; trowsdale and parham ) . the lectins cd and cd l represent a prototypic model of a duplicated progeny of ancestral genes that interact with a vast spectrum of pathogens. our results clearly indicate that these duplicated genes have evolved, and might still evolve, under completely different evolutionary pressures. whereas one, cd , shows signals of strong conservation, its paralogue, cd l, exhibits an excess of sequence diversity compatible with the action of balancing selection. in addition, the strong contrast observed in length variation of the neck region between the two genes may have important consequences in medical genetics. in this context, association studies are now needed that correlate length variation of the neck region and susceptibility to infectious diseases whose etiological agents are known to interact with one (or both) of these lectins. more generally, our study has revealed that even a short segment of the human genome can help uncover an extraordinarily complex evolutionary history, including different pathogen pressures on host immunity genes, as well as traces of ancient population structure in the african continent. the coming years will certainly bring unprecedented large data sets of sequence diversity, genomewide and populationwide, with each genomic region possibly revealing a different aspect of human history. the integration of all these apparently independent pieces of the same reality will provide us with a much broader and more realistic view of the demographic history of the human species, as well as of human adaptation to the different environmental conditions imposed not only by pathogens but also by other major factors such as climate and nutritional resources. gold-graphical overview of linkage disequilibrium population history and natural selection shape patterns of genetic variation in genes interrogating a high-density snp map for signatures of natural selection c-type lectins dc-sign and l-sign mediate cellular entry by ebola virus in cis and in trans cutting edge: carbohydrate profiling identifies new pathogens that interact with dendritic cell-specific icam- -grabbing nonintegrin on dendritic cells signatures of natural selection in the human genome a strong signature of balancing selection in the cis-regulatory region of ccr a dendritic cell-specific intercellular adhesion molecule -grabbing nonintegrin (dc-sign)-related protein is highly expressed on human liver sinusoidal endothelial cells and promotes hiv- infection novel member of the cd (dc-sign) gene family in primates helicobacter pylori modulates the t helper cell /t helper cell balance through phase-variable interaction between lipopolysaccharide and dc-sign proteomic analysis of dc-sign on dendritic cells detects tetramers required for ligand binding but no association with cd a human genome diversity cell line panel through the looking glass. macmillan, london cavalli-sforza ll ( ) population structure and human evolution the application of molecular genetic approaches to the study of human evolution dendritic cell (dc)-specific intercellular adhesion molecule (icam- )-grabbing nonintegrin (dc-sign, cd ), a c-type surface lectin in human dcs, is a receptor for leishmania amastigotes toll-like receptors and the genetics of innate immunity genetics of susceptibility to human infectious disease description and power analysis of two tests for detecting recent population bottlenecks from allele frequency data sequence and expression of a membrane-associated c-type lectin that exhibits cd -independent binding of human immunodeficiency virus envelope glycoprotein gp human demographic history: refining the recent african origin model hitchhiking under positive darwinian selection extended neck regions stabilize tetramers of the receptors dc-sign and dc-signr the population genetics of the haemoglobinopathies the lectin-complement pathway-its role in innate immunity and evolution l-sign (cd l) is a liverspecific capture receptor for hepatitis c virus deep haplotype divergence and long-range linkage disequilibrium at xp . provide evidence that humans descend from a structured ancestral population evidence for archaic asian ancestry on the human x chromosome dc-sign, a dendritic cell-specific hiv- -binding protein that enhances trans-infection of t cells identification of dc-sign, a novel dendritic cell-specific icam- receptor that supports primary immune responses self-and nonself-recognition by c-type lectins on dendritic cells mycobacteria target dc-sign to suppress dendritic cell function evidence for positive selection and population structure at the human mao-a gene human migrations and population structure: what we know and why it matters sampling theory for neutral alleles in a varying environment human cytomegalovirus binding to dc-sign is required for dendritic cell infection and target cell trans-infection disease and evolution detection of the signature of natural selection in humans: evidence from the duffy blood group locus hierarchical patterns of global human y-chromosome diversity archaic african and asian lineages in the genetic ancestry of modern humans a structured ancestral population for the evolution of modern humans genetic perspectives on human origins and differentiation x chromosome evidence for ancient human histories a neutral explanation for the correlation of diversity with recombination rates in humans natural selection at 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nucleotide polymorphisms from sequencing data dc-sign (cd ) mediates dengue virus infection of human dendritic cells haplotype diversity and linkage disequilibrium at human g pd: recent origin of alleles that confer malarial resistance patterns of human genetic diversity: implications for human evolutionary history and disease mini-review: defense strategies and immunity-related genes y chromosome sequence variation and the history of human populations positive selection on the human genome van die i ( ) molecular basis of the differences in binding properties of the highly related c-type lectins dc-sign and l-sign to lewis x trisaccharide and schistosoma mansoni egg antigens a new evolutionary law evidence for balancing selection from nucleotide sequence analyses of human g pd metapopulation models for historical inference mitochondrial dna variation in human evolution and disease initial sequencing and comparative analysis of the mouse genome patterns of ancestral human diversity: an analysis of aluinsertion and restriction-site polymorphisms on the number of segregating sites in genetical models without recombination common bglobin rflp haplotypes harbour a surprising level of ancestral sequence mosaicism human evolution the human genus natural selection and molecular evolution in ptc, a bitter-taste receptor gene evolution in mendelian populations worldwide dna sequence variation in a -kilobase noncoding region on human chromosome we warmly acknowledge guillaume laval for useful suggestions on the use of simcoal software, laurent excoffier and francesca luca for stimulating discussions, and two reviewers for constructive comments on the first version of the manuscript. l.b.b. was supported by fundaçã o para a ciência e a tecnologia fellowship sfrh/bd/ / . the urls for data presented herein are as follows: key: cord- - zjrunzc authors: faye, martin; faye, oumar; diagne, moussa moise; fall, gamou; weidmann, manfred; sembene, mbacke; sall, amadou alpha; faye, ousmane title: full-genome characterization and genetic evolution of west african isolates of bagaza virus date: - - journal: viruses doi: . /v sha: doc_id: cord_uid: zjrunzc bagaza virus is a mosquito-borne flavivirus, first isolated in in central african republic. it has currently been identified in mosquito pools collected in the field in west and central africa. emergence in wild birds in europe and serological evidence in encephalitis patients in india raise questions on its genetic evolution and the diversity of isolates circulating in africa. to better understand genetic diversity and evolution of bagaza virus, we describe the full-genome characterization of west african isolates, sampled from to . parameters such as genetic distances, n-glycosylation patterns, recombination events, selective pressures, and its codon adaptation to human genes are assessed. our study is noteworthy for the observation of n-glycosylation and recombination in bagaza virus and provides insight into its indian origin from the th century. interestingly, evidence of bagaza virus codon adaptation to human house-keeping genes is also observed to be higher than those of other flaviviruses well known in human infections. genetic variations on genome of west african bagaza virus could play an important role in generating diversity and may promote bagaza virus adaptation to other vertebrates and become an important threat in human health. bagaza virus (bagv) belongs to the flaviridae family, flavivirus genus and ntaya serological group. bagv is a mosquito-transmitted virus, which was first isolated in the bagaza district of the central african republic (car), in , from a pool of mixed-species female culex spp. mosquitoes during entomological investigations [ ] . as is characteristic of flaviviruses, bagv possesses a linear single-stranded, positive-sense rna genome [ ] . the bagv genome is , nucleotides in length, encoding a single polyprotein ( amino acids) from which viral proteins are derived, and flanked by and untranslated regions (utrs) of and nt, respectively [ ] . bagv has been isolated repeatedly with a high titer from different species of mosquitoes in central and west african countries [ ] [ ] [ ] , and in india, where serological investigations suggested subclinical infections in humans [ , ] . despite this widespread circulation of bagv, outbreaks involving humans or animals have not yet been reported from these countries. subsequently, in september , bagv was associated with a high mortality among game birds (partridges and pheasants) in southern spain, the first detection of bagv in europe and the first isolation from a vertebrate host [ , ] . however, it is not surprising that bagv infects birds since it has been shown to be synonymous with israel turkey all virus strains analyzed in this study were derived from the who collaborating center (http://apps.who.int/whocc/detail.aspx?cc_ref=sen- &cc_code=sen) for arboviruses and viral hemorrhagic viruses in senegal at institut pasteur de dakar (dakar, senegal) ( table ). viral stocks were prepared by inoculating viral strains into aedes albopictus (c / ) cell line in leibovitz (l- ) growth medium viruses , , of (gibcobrl, grand island, ny, usa) supplemented with % fetal bovine serum (fbs) (gibcobrl, grand island, ny, usa), % tryptose phosphate and antibiotics (sigma, gmbh, germany). bagv infection was confirmed after days of propagation by immunofluorescence assay (ifa) using specific hyper-immune mouse ascitic fluid, as previously described [ ] . cultures supernatants were collected for virus rna isolation. extraction of viral rna from supernatants was performed with the qiaamp viral rna mini kit (qiagen, heiden, germany) according to manufacturer's instructions. extracted rna was frozen at − • c prior to downstream applications. real-time rt-pcr (reverse transcriptase-polymerase chain reaction) was performed using the quantitect ® probe rt-pcr kit (qiagen, heiden, germany) in a final volume of µl following previously established protocols and primers [ ] . reverse-transcription was performed using the amv kit (promega, madison, wi, usa) following manufacturer's instructions and cdna were stored at − • c. the polymerase chain reaction with each primer set was carried out in a final volume of µl using the gotaq ® dna polymerase kit (promega, madison, wi, usa) according to manufacturer's instructions. briefly, µl (around µg) of cdna was added to µl of a rt-pcr mix containing mm mgcl , mm of dntp, x reaction buffer, u gotaq polymerase, . µl of nuclease-free water and pmols of each primer (sense and antisense). pcr was carried using the following conditions: an initial incubation at • c for min, followed by cycles of • c for min, min at melting temperature of primers, and • c according to the length of pcr product and • c during min. subsequently, µl of each pcr product was analyzed by gel electrophoresis on % agarose gels stained with ethidium bromide to check the size of amplified fragments by comparison to a dna molecular weight marker (hyperladder™ kb, bioline, taunton, ma, usa). the dna bands from the pcr amplification were purified (qiaquick gel extraction kit, qiagen, heiden, germany) and sequenced from both ends for each positive sample (beckmann coulter, high wycombe, uk). sequencing of the and termini of the viral genome was performed using a race kit (invitrogen, carlsbad, ca, usa) and a race kit (roche, basel, switzerland) following the manufacturer's protocols. additional sequences representing strains from central african republic, india, strain related to spanish wild bird's outbreak in , the itv and the ntaya virus were obtained from genbank, with the following accession numbers, respectively: ay , eu , hq , kc and nc_ . full-length genome sequences bagv isolates were obtained by assembling overlapping nucleotide sequences using the unipro ugene software (http://ugene.net/download.html) [ ] . multiple alignments of full-genome sequences were carried out by using muscle algorithm (http://www.drive .com/muscle/) [ ] within unipro ugene software. based on these alignments, we investigated the genetic properties of these different isolates circulating in west africa, such as genome length and location of main conserved amino acid motifs previously described in mosquito-borne flaviviruses (mbfvs) with sometimes mutations which include no physicochemical properties changes [ ] . comparatively, conservation of these motifs was also assessed in culex flavivirus (cxfv) and aedes flavivirus (aefv) (insect-specific flaviviruses; (isfs)) and in modoc virus (modv) and rio bravo virus (rbv) (vertebrate-specific flaviviruses, also known as no known vector flaviviruses (nkvfs)). we also searched for evidence of informative amino acid sites among bagv sequences using the divein web server (https://indra.mullins.microbiol.washington.edu/divein/) [ ] . the genetic divergence between previously available bagv complete genomes and new characterized sequences was also assessed at the nucleotide and protein levels. prediction of n-glycosylated sites on the genome of bagv were performed by submitting complete polyproteins on online version of netnglyc . server (http://www.cbs.dtu.dk/services/ netnglyc/). n-linked glycosylation is a post-translational event whereby carbohydrates are added to asparagines, which occur in the consensus sequence asn-xaa-ser/thr, where xaa is any amino acid except proline. "potential" scores of predicted n-glycosylated sites across the protein chain from n-to c-terminal were illustrated using the default threshold of . and the "jury agreement" indicates how many of the nine networks support the prediction [ ] . the rnaz method [ ] implemented in the vienna rna websuite (http://rna.tbi.univie.ac.at/) [ ] was used to detect thermodynamically stable and evolutionarily conserved structural rna domains on complete non-coding regions of the west african bagv isolates characterized in this study and the isolates from spain and car, because complete non-coding sequences are not currently available for the isolate from india. the rnaz method use an algorithm which testing a large set of well-known conserved structural rna domains and reports a "rna classification probability" or p-value as a measure of thermodynamic stability. structural rna domains with p > . are classified as stable [ ] . furthermore, the optimal secondary structures were predicted with a minimum free energy using the rnaalifold method [ ] implemented also in the vienna rna websuite that use a dynamic programming algorithm with rna parameters as previously described [ ] . furthermore, previously described organization of conserved sequences (cs) [ ] was analyzed on predicted secondary structures of the utr, considering possible repetitions of these cs. thus, a conserved sequence was considered as imperfect when it presented three or more differences with corresponding consensus sequence previously described [ ] , marked by a deletion, an insertion, or a substitution. a bayesian phylogenetic analysis for estimation of data quality and selection of the best-fit nucleotide substitution model were performed using mega . (https://www.megasoftware.net/) with a discrete gamma distribution (+g) with rate categories. thus, a total of different nucleotide substitution models were tested and model with the lowest bic score (bayesian information criterion) was considered to describe the best substitution pattern. further parameters as aicc value (akaike information criterion, corrected) and maximum likelihood value (lnl) are also estimated [ ] . a maximum likelihood tree was then constructed with complete polyprotein sequences from insect-specific flaviviruses, no known vector flaviviruses, tick-born flaviviruses, mosquito-borne flaviviruses, the orfs from new characterized west african bagv isolates and bagv sequences previously available from spain (hq - , kr - ), india (eu ) and car (ay ). tree was inferred using fasttree v . . (http://www.microbesonline.org/fasttree/) [ ] , where nucleotide substitution was modeled using general time-reversible with a proportion of invariant sites (gtr+i). nodes were labeled with local support values, which were computed with the shimodaira-hasegawa test (sh-like) for replications. topology was visualized by figtree v. . . (http://tree.bio.ed.ac.uk/software/figtree/). to prevent potential biases during phylogenetic inference due to recombination, all polyprotein sequences were analyzed using seven methods (rdp, geneconv, maxchi, bootscan, chimaera, siscan, and seq) implemented in the recombination detection program (rdp beta . ) to uncover evidence for recombination events [ ] . the disentangle recombination signals option was "on" and the linear sequence setting was used. the remaining settings were kept at their default values. only events with p-values < × − that were detected by four or more methods were considered to represent strong evidence for recombination using permutations and the bonferroni correction [ ] implemented in the rdp program to prevent false positive results. a chi-square test was used to determine if the sequence identity between a recombinant isolate and a given parent was significantly different both inside and outside the recombinant region. in addition, a bootscan analysis including the recombinant and the parental strains determined above was also performed to confirm these putative recombination events. the occurrence of recombination in bagv genomes was also investigated with a method called genetic algorithms for recombination detection (gard) implemented in datamonkey web server (http://datamonkey.org) [ ] , that estimates breakpoints based on a genetic algorithm. the statistical significance of putative breakpoints was evaluated through kishino-hasegawa (hk) tests; breakpoints were considered significant if their p value was < . . separate neighbor-joining (nj) trees were constructed for identified putative recombinant region and non-recombinant alignment partitions dictated by the breakpoint locations. phylogenetic trees were inferred using the percentage of bootstrap replications under the appropriate model of nucleotide substitution. recombination can mislead inference of positive natural selection if it is not properly accounted for. if recombination was identified, these potential recombinant sequences were excluded from further analyses to avoid inferential biases [ ] . the non-synonymous/synonymous rate ratio (dn/ds) is a widely used method to detect positive selection. the statistical test dn/ds permitted to distinguish diversifying or positive selection (dn/ds > ) from negative or purifying selection (dn/ds < ). positive selection is inferred when the rate of non-synonymous (dn) substitutions is higher than that of synonymous (ds) substitutions (dn > ds). episodes of positive selection in each gene of bagv were analyzed using methods of estimation among individual sites and internal sites on branches of the phylogenetic tree. for this, a total of alignment partitions were performed corresponding to c, prm, e, ns , ns a, ns b, ns , ns a, ns b and ns proteins. as site model, we used the single-likelihood ancestor counting (slac) that estimated the difference between non-synonymous (dn) and synonymous (ds) rates per codon site at . significance level. the fast unconstrained bayesian approximation (fubar) method which evaluated episodic positive selection at each site in the alignment at posterior probability ≥ . was also used [ ] . the mixed effects model of evolution (meme) was also conducted at a . significance level for estimation selective pressure changes among codon sites. finally, branch-site random effects likelihood (branch-site rel) analysis was used to evaluate evidence of diversifying selection on specific branches in the phylogenetic tree at a proportion of sites, considering p-values less than . as significant. all four methods were conducted with hyphy package implemented in datamonkey web server [ ] . an episode of positive diversifying selection in concern of a region was considered if it was detected by at least two different methods. the evolutionary analysis was performed using a strict clock gmrf bayesian skyride coalescent tree prior [ , ] . the gtr substitution model was used with gamma rate categories. the bayesian markov chain monte carlo (mcmc) algorithms using beast v . . (http://beast.community/) [ ] were employed to estimate the rate of bagv evolution from first isolation to . mcmc analyses were run for million generations, sampling every thousand to ensure convergence of estimates. population size (ess) above was assessed using the analysis program tracer v . (http://beast.bio.ed.ac.uk/tracer). the posterior distribution of trees obtained from the beast analysis was also used to obtain the bayesian maximum clade credibility (mcc) tree for these sequences generated by treeannotator v. . . (http://beast.community/treeannotator) (from million) after removing % of the runs burn-in and visualized by figtree v. . . . the codon adaptation index (cai) is a measure of the synonymous codon usage bias making comparisons of codon usage preferences in different organisms and assessing the adaptation of viral genes to their hosts [ , ] . cai was applied in many recent studies involving humans and rna viruses [ ] [ ] [ ] . to know if there is evidence of bagv adaptation for codon usage in humans, the cai was calculated for each isolate. to calculate normalized cai, full-length polyprotein sequences of west african bagv isolates and previously available bagv sequences from spain were compared to that of human using caical v . program (http://genomes.urv.es/caical/) [ ] . first, we obtained a "raw" cai (rcai) and then, the cai was normalized by the "expected neutral cai" (ecai) value based on random viral sequences using similar length, codon composition, gc-content and human amino acid usage. indeed, a table for human codon usage containing the entirety of human coding genes is publicly available [ ] . based on this table, we created a new table where only the identified human housekeeping genes were considered [ ] . normalized cai threshold was obtained by calculating rcai/ecai values and a value above ' ' is higher than neutral and considered as evidence of codon adaptation to the reference set of codon preferences [ ] . cai values obtained for bagv were then compared to those of others mbfvs well known to infect humans such as dengue virus (denv), usutu virus (usuv), wnv, zika virus (zikv) and yellow fever virus (yfv), nkv flaviviruses (modv and rbv) and isfs (cxfv and aefv), using the non-parametric wilcoxon test with r program. a p-value less than . was considered as significant. sequences of tobacco mosaic virus (tmv) were compared to human codons and used as negative control to provide an example that results for codon adaptation to human house-keeping genes are robust and not false positives or anomalies. as there are no known cases of human infection, or evidence of human adaptation for tmv, we expected all sequences to have a lower cai threshold than the calculated cai. in this study, a total of full-genome sequences ( , bp) of west african bagv isolates were obtained by sequencing overlapping pcr amplifications covering the genome and by using race (rapid amplification of cdna ends) techniques for the terminal ends and deposited in genbank (www.ncbi.nlm.nih.gov/genbank/) (accession numbers: mf - ) ( table ). analysis of new characterized bagv complete open reading frames (orfs) was performed at nucleotide and amino acid levels including previously available sequences from car (isolate dakarb _car_ , accession no. ay ) and spain (isolate spain_h_ , accession no. hq ) into multiple sequence alignments. the polyprotein length of the newly sequenced west african bagv isolates was determined with respect to gene sizes (table ) . although the utr was similar in length, the utr of these west african isolates was either nt or nt longer than those of sequences from car and spain, respectively. in the utr, positions , and had nucleotide changes that were distinguishable for west african isolates. nucleotide changes a to c at position and t to c at position were seen in west african sequences, and a t to c change at position was observed only in sequences of the isolates ard _dakar-bango_sen_ and ara _dezidougou_ci_ . interestingly, the utr can be divided into three sections; a proximal highly variable section constituted by the first nucleotides following the stop codon, a second highly conservative section located between nucleotide positions and and a moderately variable distal region comprising the last nucleotides. in this distal section, utr sequences of west african isolates presented insertions of nt and nt, compared to the isolates from car and spanish (kr - ), respectively. pairwise genetic distances of coding sequences were evaluated at nucleotide and amino acid levels between isolates characterized in this study and in comparison with previously available bagv sequences ( figure ). nucleotide sequences of bagv isolated from senegal showed a mean distance of . % ± . % ( . - . %). this lowest genetic distance was also apparent at amino acid level with a mean distance of . % ± . % ( . - . %). here, we described location of main conserved amino acid motifs on bagv proteins using in silico analysis of complete genome sequences of the west african bagv isolates characterized in this study and sequences from india, car and spain. most of highly conserved amino acid motifs localized across e, ns , ns and ns proteins of mvfs were identified in the bagv genomes, sometimes with presence of conservative amino acid mutations (positions highlighted in black) or non-conservative amino acid mutations (positions highlighted in red) ( table ) in protein ns , all analyzed motifs were conserved, but nc t p and t a were observed in sequences of isolates ard _barkedji_sen_ and eu _ _india_ , respectively. the bagv isolate ard _dakar-bango_sen_ also contains nc p t. in ns , the conserved motif identified at positions - contains nc a p and p l for bagv isolates ard _diawara_sen_ and ard _diawara_ sen_ , whereas nc l s in comparison to sequence of the isolate ara _dezidougou_ci_ from côte d'ivoire, senegalese bagv isolates showed a higher mean distance of . % ± . % ( . - . %) at nucleotide level. however, this highest genetic distance was less apparent at amino acid level with a mean distance of . % ± . % ( . - . %). furthermore, mean distances of . % ( . - . %), . % ( . - . %), . % ( . - . %) were recorded at nucleotide level between senegalese bagv isolates and the isolate from car, spain, and eu __ _india_ , respectively while respective mean distances were . % ( . - . %), . % ( . - . %), . % ( . - . %) at amino acid level. a differentiation coefficient value of . was also observed between these west african bagv isolates and previously available sequences. here, we described location of main conserved amino acid motifs on bagv proteins using in silico analysis of complete genome sequences of the west african bagv isolates characterized in this study and sequences from india, car and spain. most of highly conserved amino acid motifs localized across e, ns , ns and ns proteins of mvfs were identified in the bagv genomes, sometimes with presence of conservative amino acid mutations (positions highlighted in black) or non-conservative amino acid mutations (positions highlighted in red) ( table ) in protein ns , all analyzed motifs were conserved, but nc t p and t a were observed in sequences of isolates ard _barkedji_sen_ and eu _ _india_ , respectively. the bagv isolate ard _dakar-bango_sen_ also contains nc p t. in ns , the conserved motif identified at positions - contains nc a p and p l for bagv isolates ard _ diawara_sen_ and ard _diawara_ sen_ , whereas nc l s is present in ard _diawara_sen_ , and ard _barkedji_sen_ . a non-conserved motif at positions - contained nc f l in all bagv sequences analyzed and isolate ard _diawara_sen_ contained additional nc t p and d y. a non-conserved motif in ns at positions - contained nc t n in all bagv sequences. bagv isolate ard _dakar-bango_sen_ has two supplementary mutations s w and s p. in addition, these mbfvs amino acid motifs were also mostly conserved in bagv, nkvfs and cxfv (isfs) than in aefv (isfs). non-conservative amino acid mutations on the bagv polyprotein might be associated to phenotypic differences of bagv isolates. in addition, the presence of phylogenetically informative sites was assessed on the divein web server. the identified site lap is harbored by the conserved motif laptrvv previously identified in ns protein of flaviviruses [ ] and presents nc mutations in the genome of three bagv isolates. in addition, phylogenetically informative sites iega and griwna identified in ns b and ns , showed combined variations in the genome of the car isolate (dkgq and rtdmec, respectively) and the senegalese bagv isolates ard _diawara_sen_ (rraa and griwna, respectively) and ard _barkedji_sen_ (rrss and rtdmec, respectively) ( figure ). non-conservative amino acid mutations on the bagv polyprotein might be associated to phenotypic differences of bagv isolates. in addition, the presence of phylogenetically informative sites was assessed on the divein web server. the identified site lap is harbored by the conserved motif laptrvv previously identified in ns protein of flaviviruses [ ] and presents nc mutations in the genome of three bagv isolates. in addition, phylogenetically informative sites iega and griwna identified in ns b and ns , showed combined variations in the genome of the car isolate (dkgq and rtdmec, respectively) and the senegalese bagv isolates ard _diawara_sen_ (rraa and griwna, respectively) and ard _barkedji_sen_ (rrss and rtdmec, respectively) ( figure ). prediction of n-glycosylation sites was performed using complete genome sequences of the west african bagv isolates characterized in this study and sequences from india, car and spain on the divein web server. the "potential" score represents the averaged output of nine neural networks and the "jury agreement" indicates how many of the nine networks support the prediction. in total, eight n-glycosylated motifs were identified in the bagv genome (potential > . ) including two highly probable sites (potential > . and jury agreement of / ). despite high potential ( . ) and jury agreement ( / ), the motif (asn-x-thr) nptd identified at position was not considered to be glycosylated because it contained a proline known to preclude the n-glycosylation by rendering inaccessible the asparagine in the majority of cases (figure ). this motif was in the domain iii region prediction of n-glycosylation sites was performed using complete genome sequences of the west african bagv isolates characterized in this study and sequences from india, car and spain on the divein web server. the "potential" score represents the averaged output of nine neural networks and the "jury agreement" indicates how many of the nine networks support the prediction. in total, eight n-glycosylated motifs were identified in the bagv genome (potential > . ) including two highly probable sites (potential > . and jury agreement of / ). despite high potential ( . ) and jury agreement ( / ), the motif (asn-x-thr) nptd identified at position was not considered to be glycosylated because it contained a proline known to preclude the n-glycosylation by rendering inaccessible the asparagine in the majority of cases (figure ). this motif was in the domain iii region of the e protein of all bagv isolates. however, a second (asn-x-ser) motif nfsl was highly predicted (score . ( / )) and suggested an n-linked glycosylation site at the residue asn- in the ns b protein. interestingly, we also found six others probable n-glycosylation at different positions on the bagv polyprotein including one site (nysi) harboring, the nys motif at the th position ( th position of the e protein), previously described as a virulence factor for wnv and denv. of the e protein of all bagv isolates. however, a second (asn-x-ser) motif nfsl was highly predicted (score . ( / )) and suggested an n-linked glycosylation site at the residue asn- in the ns b protein. interestingly, we also found six others probable n-glycosylation at different positions on the bagv polyprotein including one site (nysi) harboring, the nys motif at the th position ( th position of the e protein), previously described as a virulence factor for wnv and denv. the "potential" score is the averaged output of nine neural networks and the "jury agreement" indicates how many of the nine networks support the prediction. the n-glyc result column shows one of the following outputs for predictions. nglycosylated sites highly predicted by the nine networks (potential > . and jury agreement of / ) are highlighted in red and the site previously reported as virulence factor on e protein of flaviviruses is colored in blue. assessment of thermodynamically stable and evolutionarily conserved structural rna domains was performed using complete non-coding sequences of the west african bagv isolates characterized in this study and the isolate from spain. the rnaz method implemented in the vienna figure . prediction of n-glycosylation on bagaza virus genome. predictions were performed using the netnglyc . server. a position with a potential (green vertical lines) crossing the threshold (horizontal red line at . ) is predicted glycosylated. the "potential" score is the averaged output of nine neural networks and the "jury agreement" indicates how many of the nine networks support the prediction. the n-glyc result column shows one of the following outputs for predictions. n-glycosylated sites highly predicted by the nine networks (potential > . and jury agreement of / ) are highlighted in red and the site previously reported as virulence factor on e protein of flaviviruses is colored in blue. assessment of thermodynamically stable and evolutionarily conserved structural rna domains was performed using complete non-coding sequences of the west african bagv isolates characterized in this study and the isolate from spain. the rnaz method implemented in the vienna rna websuite was used to identify conserved structural rna domains in the utrs of bagv characterized by a p > . . using the rnaz method, highly conserved structural rna domains was not identified in the utr of bagv genome while a total of four highly conserved structural rna domains were determined in the region with respective classification probabilities of . , . , . and . ( figure s ). however, the rnaalifold method implemented in the vienna rna websuite server predicted that, as in the genome of other members of the genus flavivirus, bagv has a shorter utr (≈ nt), consisting of a pair of conserved stem-loops (sl-a and sl-b) (figure ) . sl-a serves as promoter of viral polymerase activity followed by a shorter loop which contains a cyclisation sequence upstream of the aug (sl-b) . the secondary structure of bagv's utr could be divided in three parts; a highly variable domain following the stop codon and consisting in an au-rich stem-loop (sl-i), a second domain with highly conserved sequence and two stem-loops (sl-ii and sl-iii) and dumbbell structures (db and db ), and the moderately conserved distal domain which contains the complementary cyclisation elements. in the intermediate domain, the sl-ii presented a pseudoknot pk preceding a short conserved loop (rcs ). this structural motif was repeated in a stem-loop sl-iii with pk and cs . these stem-loops were followed by dumbbell structures db and db that presented conserved loop rcs connected with a pseudoknot pk and its repetition cs , respectively [ ] . thus, organization of conserved sequences on consensus secondary structure of bagv's utr was structured rcs -cs -rcs -cs -imcs . indeed, cs was imperfect (imcs ) only on sequences of west african bagv isolates with a total of nine substitutions compared to the corresponding consensus sequence previously described [ ] . viruses , , x of rna websuite was used to identify conserved structural rna domains in the utrs of bagv characterized by a p > . . using the rnaz method, highly conserved structural rna domains was not identified in the ′ utr of bagv genome while a total of four highly conserved structural rna domains were determined in the ′ region with respective classification probabilities of . , . , . and . ( figure s ). however, the rnaalifold method implemented in the vienna rna websuite server predicted that, as in the genome of other members of the genus flavivirus, bagv has a shorter ′ utr (≈ nt), consisting of a pair of conserved stem-loops (sl-a and sl-b) (figure ) . sl-a serves as promoter of viral polymerase activity followed by a shorter loop which contains a cyclisation sequence upstream of the ′ aug (sl-b) . the secondary structure of bagv's ′ utr could be divided in three parts; a highly variable domain following the stop codon and consisting in an au-rich stem-loop (sl-i), a second domain with highly conserved sequence and two stem-loops (sl-ii and sl-iii) and dumbbell structures (db and db ), and the moderately conserved distal domain which contains the complementary cyclisation elements. in the intermediate domain, the sl-ii presented a pseudoknot pk preceding a short conserved loop (rcs ). this structural motif was repeated in a stem-loop sl-iii with pk and cs . these stem-loops were followed by dumbbell structures db and db that presented conserved loop rcs connected with a pseudoknot pk and its repetition cs , respectively [ ] . thus, organization of conserved sequences on consensus secondary structure of bagv's ′ utr was structured rcs -cs -rcs -cs -imcs . indeed, cs was imperfect (imcs ) only on sequences of west african bagv isolates with a total of nine substitutions compared to the corresponding consensus sequence previously described [ ] . the bayesian phylogenetic analysis for estimation of data quality and selection of the best-fit nucleotide substitution model were performed using mega . with a discrete gamma distribution (+g) with rate categories. the general time-reversible with a discrete gamma distribution and a proportion of invariant sites (gtr+i) was the best nucleotide substitution model for our sequences data presenting score values of the bayesian phylogenetic analysis for estimation of data quality and selection of the best-fit nucleotide substitution model were performed using mega . with a discrete gamma distribution (+g) with rate categories. the general time-reversible with a discrete gamma distribution and a proportion of invariant sites (gtr+i) was the best nucleotide substitution model for our sequences data presenting score values of , . , , . and − , . for bic, aicc and lnl criteria, respectively. the maximum likelihood (ml) tree was inferred using fasttree v . . [ ] on our total data set including the complete polyprotein sequences of west african bagv isolates circulating in senegal and côte d'ivoire from to , the bagv sequences from spain, the bagv sequences from india and car and complete polyproteins from different flaviviruses, with , bp alignment length ( figure ). a gtr+i model was used, as selected by bayesian criteria. nodes were labeled with local support values computed with bootstrap replications using the shimodaira-hasegawa (sh) test. the phylogeny of complete bagv genome sequences presented evidence of a single bagv phylogenetic group. furthermore, we observed also that israel meningo-encephalitis turkey virus (itv) was closed to bagv in genetic relatedness [ ] . viruses , , x of respectively. the maximum likelihood (ml) tree was inferred using fasttree v . . [ ] on our total data set including the complete polyprotein sequences of west african bagv isolates circulating in senegal and côte d'ivoire from to , the bagv sequences from spain, the bagv sequences from india and car and complete polyproteins from different flaviviruses, with , bp alignment length ( figure ). a gtr+i model was used, as selected by bayesian criteria. nodes were labeled with local support values computed with bootstrap replications using the shimodaira-hasegawa (sh) test. the phylogeny of complete bagv genome sequences presented evidence of a single bagv phylogenetic group. furthermore, we observed also that israel meningoencephalitis turkey virus (itv) was closed to bagv in genetic relatedness [ ] . given the major implications of recombination events for evolution, pathogenicity, or diagnosis of non-segmented positive rna viruses like flaviviruses [ ] , it is clearly important to determine their occurrence in the bagv genome. the rdp beta . program used for assessment of recombination events on complete polyprotein sequences [ ] revealed evidence of only one highly credible recombination event from the e protein to ns b, with estimated breakpoints at positions and of bagv genome. this recombination event involved the isolate ard _dakar-bango_sen_ originating from saint-louis, in the north of senegal ( figure ). considering the isolates ard _ barkedji_sen_ and ard _barkedji_sen_ as respective minor and major parents of the isolate ard _dakar-bango_sen_ (similarity of . % and %, respectively), this recombination event was found by rdp, geneconv, bootscan, maxchi, chimaera, sisscan and seq methods and supported by significant p-values of . × - , . × − , . × − , . × − , . × − , . × − and . × − , respectively. the bootscan and gard analyzes identified one significant recombination breakpoint at nucleotide position corresponding to the e protein, supported by a lhs p-value of . and a rhs p-value of . . this breakpoint divides the bagv genome into two regions: one that encodes the structural proteins and another that encodes the non-structural proteins. phylogenetic trees were constructed using bootstrap replications and midpoint rooted for clarity only (figure ). this recombination event led to a mismatch between nj phylogenetic trees constructed using comparison of nucleotides sequences of recombinant (positions - ) and non-recombinant genomic regions (positions - and - , ). the tree is midpoint-rooted, nodes are labeled with local support values computed using the shimodaira-hasegawa (sh) test for bootstrap replications, species names are color-coded as follows: new characterized bagv isolatesdark blue with dots; previous sequences of bagv-dark blue; mosquito-borne flaviviruses (mbfvs)-green; dual-host affiliated isfs (disfs)-red; no known vector (nkv) flavivirusesyellow; tick-born flaviviruses (tbfvs)-light blue; classical isfs (cisfs)-orange. given the major implications of recombination events for evolution, pathogenicity, or diagnosis of non-segmented positive rna viruses like flaviviruses [ ] , it is clearly important to determine their occurrence in the bagv genome. the rdp beta . program used for assessment of recombination events on complete polyprotein sequences [ ] revealed evidence of only one highly credible recombination event from the e protein to ns b, with estimated breakpoints at positions and of bagv genome. this recombination event involved the isolate ard _dakar-bango_sen_ originating from saint-louis, in the north of senegal (figure ). considering the isolates ard _barkedji_sen_ and ard _barkedji_sen_ as respective minor and major parents of the isolate ard _dakar-bango_sen_ (similarity of . % and %, respectively), this recombination event was found by rdp, geneconv, bootscan, maxchi, chimaera, sisscan and seq methods and supported by significant p-values of . × - , . × − , . × − , . × − , . × − , . × − and . × − , respectively. the bootscan and gard analyzes identified one significant recombination breakpoint at nucleotide position corresponding to the e protein, supported by a lhs p-value of . and a rhs p-value of . . this breakpoint divides the bagv genome into two regions: one that encodes the structural proteins and another that encodes the non-structural proteins. phylogenetic trees were constructed using bootstrap replications and midpoint rooted for clarity only (figure ). this recombination event led to a mismatch between nj phylogenetic trees constructed using comparison of nucleotides sequences of recombinant (positions - ) and non-recombinant genomic regions (positions - and - , ). the structural and non-structural coding regions were analyzed separately for estimation of sites and branches under positive diversifying selection, applying four different methods to ensure consistency of these events along of bagv sequences. using this approach, we found several sites under strong negative selection and most of them were in the e, ns and ns proteins (table ) . however, the significant evidence (p < . ) of episodic positive selection was obtained for all the coding genes, except for the prm, ns b and ns a regions. all positively selected sites estimated by the fubar model (posterior probability ≥ . ) were also identified by the meme method (p < . ). thus, an important number of positively selected sites were detected; interestingly, the majority of such sites were in the e, ns and ns proteins. branch-site analysis showed also a total of branches evaluating under positive selection (p < . ) and the highest proportion was in the e and ns proteins. the structural and non-structural coding regions were analyzed separately for estimation of sites and branches under positive diversifying selection, applying four different methods to ensure consistency of these events along of bagv sequences. using this approach, we found several sites under strong negative selection and most of them were in the e, ns and ns proteins (table ) . however, the significant evidence (p < . ) of episodic positive selection was obtained for all the coding genes, except for the prm, ns b and ns a regions. all positively selected sites estimated by the fubar model (posterior probability ≥ . ) were also identified by the meme method (p < . ). thus, an important number of positively selected sites were detected; interestingly, the majority of such sites were in the e, ns and ns proteins. branch-site analysis showed also a total of branches evaluating under positive selection (p < . ) and the highest proportion was in the e and ns proteins. pervasive diversifying selection at posterior probability ≥ . with fubar model; episodic diversifying selection at . significance level with slac and meme models; episodic diversifying selection at p-value p ≤ . with branch-sites rel model. mcmc convergence was obtained for three independent runs with million generations, which were sufficient to obtain a proper sample for the posterior at mcmc stationarity assessed by effective sample sizes (ess) above for each gene. furthermore, the evolutionary rates (µ) and the highest posterior densities (hpd with % of confidence interval) were . × evidence of bagv adaptation to human house-keeping genes was analyzed by calculating cai indices using complete coding polyprotein sequences of west african bagv isolates and bagv sequences available from spain, in comparison to other mbfvs such as denv, usuv, wnv, zikv and yfv, nkv flaviviruses (modv and rbv) and isfs (cxfv and aefv). cai values > were obtained for polyprotein sequences of all bagv isolates. thus, there is evidence that bagv could have adaptation to the human genes ( figure ). modv(mean cai: . and median cai: . ), rbv (mean cai: . and median cai: . ) and yfv (mean cai: . and median cai: . ) showed the highest cai values for human housekeeping genes and were significantly different to spanish and west african bagv isolates (wilcoxon rank sum test, p-values ranging from . to . × − ). compared to those of spanish isolates, sequences of west african bagv isolates presented significantly higher cai values (mean cai: . and median cai: . , wilcoxon rank sum test, p-value < . ). in addition, they were also higher than denv serotype (denv- ) (wilcoxon rank sum test, p-value < . × − ). however, cai values of west african bagv isolates were lower than those of denv- (wilcoxon rank sum test, w = , p-value = . × − ) and comparable to cai values given by denv- and denv- (wilcoxon rank sum test, w = , p-value = . and w = , p-value = . , respectively). interestingly, cai values of west african isolates were also significantly higher than those obtained for other mbfvs well known to infect human such as usuv (wilcoxon rank sum test, p-value < . × − ), wnv (wilcoxon rank sum test, p-value < . × − ), zikv (wilcoxon rank sum test, p-value < . × − ) and isfs (means cai: . and . and median cai: . and . for cxfv and aefv, respectively) which showed low evidence evidence of bagv adaptation to human house-keeping genes was analyzed by calculating cai indices using complete coding polyprotein sequences of west african bagv isolates and bagv sequences available from spain, in comparison to other mbfvs such as denv, usuv, wnv, zikv and yfv, nkv flaviviruses (modv and rbv) and isfs (cxfv and aefv). cai values > were obtained for polyprotein sequences of all bagv isolates. thus, there is evidence that bagv could have adaptation to the human genes ( figure ). modv(mean cai: . and median cai: . ), rbv (mean cai: . and median cai: . ) and yfv (mean cai: . and median cai: . ) showed the highest cai values for human housekeeping genes and were significantly different to spanish and west african bagv isolates (wilcoxon rank sum test, p-values ranging from . to . × − ). compared to those of spanish isolates, sequences of west african bagv isolates presented significantly higher cai values (mean cai: . and median cai: . , wilcoxon rank sum test, p-value < . ). in addition, they were also higher than denv serotype (denv- ) (wilcoxon rank sum test, p-value < . × − ). however, cai values of west african bagv isolates were lower than those of denv- (wilcoxon rank sum test, w = , p-value = . × − ) and comparable to cai values given by denv- and denv- (wilcoxon rank sum test, w = , p-value = . and w = , p-value = . , respectively). interestingly, cai values of west african isolates were also significantly higher than those obtained for other mbfvs well known to infect human such as usuv (wilcoxon rank sum test, p-value < . × − ), wnv (wilcoxon rank sum test, p-value < . × − ), zikv (wilcoxon rank sum test, p-value < . × − ) and isfs (means cai: . and . and median cai: . and . for cxfv and aefv, respectively) which showed low evidence for codon adaptation towards human housekeeping genes (wilcoxon rank sum test, p-value < . × − ). although cai results for isfs were significantly lower to human housekeeping genes, we did not find any significant difference between cxfv and aefv codon adaptation. compared to codon usage of human genes, sequences of tobacco mosaic virus (tmv) showed mean and median cai values of . and . , respectively. with an increasing number of emergent and re-emergent pathogens involved in human encephalitis, it is important to try to better understand which viruses have a potential to emerge causing human infection in the future. since its first isolation, bagv was only detected in mosquito pools collected in the field during entomological investigations in west and central africa and in india [ ] . however, in , bagv was identified as the cause of an encephalitis outbreak in wild birds circulating in southern spain [ ] . in a possible host-switching event [ ] , bagv could acquire future adaptation to other vertebrates such as humans [ ] . in this study, genetic properties of bagv isolates circulating in west africa, the evolutionary phylogeny of bagv and evidence of bagv adaptation to human house-keeping genes were evaluated in comparison with different flavivirus groups. genomes of west african bagv strains isolated from mosquito pools collected in the field from to showed similarities in terms of gene lengths when compared with polyprotein sequences of previously available isolates from car and spain. low amino acid distances observed between west african isolates (< %) in comparison with previously non-west african sequences (< %) combined with the weak coefficient of differentiation (< . ) revealed evidence of a low genetic diversity of bagv sequences analyzed in this study as previously described [ ] . in addition, the west african bagv isolates were more closely related to the car isolate. genome sequences originating from bagv isolates from other geographic locations would be helpful to understand if this low diversity is secluded to west-africa. although the ′ utr was conserved between isolates, the ′ utr of west african isolates varied in terms of length and structure. as in other mosquito-borne flavivirus genomes, bagv genome harbored structural rna domains both in ′ and ′ utrs which play a major role in flaviviral replication and interactions with host proteins and regulate cellular response to infection [ , ] . with an increasing number of emergent and re-emergent pathogens involved in human encephalitis, it is important to try to better understand which viruses have a potential to emerge causing human infection in the future. since its first isolation, bagv was only detected in mosquito pools collected in the field during entomological investigations in west and central africa and in india [ ] . however, in , bagv was identified as the cause of an encephalitis outbreak in wild birds circulating in southern spain [ ] . in a possible host-switching event [ ] , bagv could acquire future adaptation to other vertebrates such as humans [ ] . in this study, genetic properties of bagv isolates circulating in west africa, the evolutionary phylogeny of bagv and evidence of bagv adaptation to human house-keeping genes were evaluated in comparison with different flavivirus groups. genomes of west african bagv strains isolated from mosquito pools collected in the field from to showed similarities in terms of gene lengths when compared with polyprotein sequences of previously available isolates from car and spain. low amino acid distances observed between west african isolates (< %) in comparison with previously non-west african sequences (< %) combined with the weak coefficient of differentiation (< . ) revealed evidence of a low genetic diversity of bagv sequences analyzed in this study as previously described [ ] . in addition, the west african bagv isolates were more closely related to the car isolate. genome sequences originating from bagv isolates from other geographic locations would be helpful to understand if this low diversity is secluded to west-africa. although the utr was conserved between isolates, the utr of west african isolates varied in terms of length and structure. as in other mosquito-borne flavivirus genomes, bagv genome harbored structural rna domains both in and utrs which play a major role in flaviviral replication and interactions with host proteins and regulate cellular response to infection [ , ] . however, differences in determination of structural rna domains in utr between the rnaz and the rnaalifold methods used in this study could be attributed to variations in algorithm of analysis used by each method [ ] [ ] [ ] [ ] . the small subgenomic rna (sfrna) identified in the utr of bagv is generated through incomplete degradation of the viral genome by cellular - exonuclease xrn [ , ] and plays an important role in viral pathogenicity [ ] and modulation of host responses [ , ] . in addition, the stable ' terminus region of the sfrna following the dumbbell structures (db and db ) and complementary to the terminus of the utr, was shown to be necessary in genomic rna cyclisation for viral replication and translation [ ] . the sfrna can be in competition with the utr of genomic rna in binding to proteins of viral replication complexes (rc) [ ] and/or cellular machinery [ ] . thus, it slows down the replication or translation and assembly of particles [ ] . the utr region is important for translation and replication of the rna genome through interactions with viral and host proteins, genome stabilization, and rna packaging [ ] . a better understanding of the potential impact of utr variations in replication of bagv could be important in the study of mechanisms implicated in their pathogenicity [ , ] . most motifs linked to virulence previously described in these proteins of other mbfvs were conserved among bagv isolates. however, some non-conservative mutations were identified in e, ns , ns and ns . in general, non-conservative amino acid mutations (nc) are spontaneous, rare, and hazardous, and then represent the main causes of genetic diversity. thus, non-conservative mutations observed on bagv genome could modulate viral phenotypes of particular isolates in mechanisms such as virus cell entry, replication, production of viral particles, and assembly, and cause modifications in post-translational regulation as previously demonstrated for other flaviviruses such as denv [ ] [ ] [ ] . the e protein is involved in cell receptor recognition, attachment, cell fusion, tropism, and virulence [ ] . ns is the most conserved non-structural protein of flaviviruses. associated with the other non-structural proteins, the ns protein plays an important function in viral replication and assembly and viral escape to host innate immune response [ ] . the ns protein is the main component of the replication machinery and ensures multiple functions in viral evasion to host antiviral response and in production and assembly of infectious viral particles [ ] . the ns protein is the largest viral protein that serves as the rna-dependent rna polymerase (rdrp) and performs multiple functions essential for viral replication, including processing the viral polyprotein, replicating the viral rna. sharing these motifs of virulence mostly with mbfvs, nkvfs and cxfv than with aefv showed that bagv could be more closely related to mbfvs transmitted by culex mosquitoes and could explain frequent bagv isolations mainly from mosquitoes of culex genus and its capacity to infect vertebrates such as wild birds [ , , , , ] . in addition, the west african bagv isolates characterized in our study were mainly isolated from culex poicilipes and culex neavei mosquitoes which have been reported as potential vectors for flaviviruses such as wnv [ ] . culex neavei was also found as a competent vector able to transmit flaviviruses such as usuv and wnv [ , ] . despite no available data on culex poicilipes competency to transmit flaviviruses, these two mosquito species belonging to culex genus could play an important role in natural transmission of bagv to vertebrates such as wild birds since another member of the culex genus, culex tritaeniorhynchus, has been found competent to transmit bagv to mice [ ] . the phylogenetically informative sites identified on the bagv genome located mainly in ns , ns b and ns proteins, respectively, could have a considerable impact in viral fitness on host for corresponding west african isolates. in addition, the prediction of the n-glycosylated sites at different positions on bagv genome such as asn in ns b and the nysi motif at th position of the e protein showed that post-translational modifications may influence acquisition or loss of capacity in mechanisms such as pathogenicity, evasion of innate immune pathways. indeed, flaviviruses ns b plays an important role in replication of viral rna facilitating the formation of replication complexes and modulating host innate immune response such as interferons, micrornas and rna interference, formation of stress granules and the unfolded protein responses [ ] [ ] [ ] . a previous study had shown that n-glycosylation of ns b of denv does not affect the protein stability but causes a considerable reduction in efficiency of viral production [ ] . presence of a glycosylation site and an informative site in the viral ns b protein could influence the efficiency of viral replication and the outer shape of the virion. the presence of the n-linked glycosylation motif nys had been previously reported at / th and th on the e protein of denv and wnv (lineage strains and some neuroinvasive lineage strains), respectively, involving in receptor binding, viral morphogenesis, viral infectivity, and tropism [ ] [ ] [ ] [ ] [ ] . since glycosylation is a means of evasion to immune recognition within the host by masking particular antigenic sites from recognition by neutralizing antibodies, it could increase the diversity of the glycosylation on viral proteins [ , ] . nevertheless, it could be important in future studies to determine whether the predicted glycosylation sites are really used (asparagine-linked) using specific enzymatic digestion by endo h and peptide n-glycosidase (pngase f) [ ] . our data suggest the ability of bagv to develop phenotypically important variations and potentially adaptation to new vertebrate hosts such as humans. however, to understand better the impact of variation on these predicted n-glycosylation sites and the identified phylogenetically important variations would require in vitro studies with reverse genetically engineered infectious clones on mosquito or mammalian cell lines and in vivo experiments in mosquitoes or in animal models like mouse [ , ] . however, antibodies against bagv proteins or infectious clone are currently not available for bagv. the identification of natural recombination events between virus isolates is important for our understanding of virus evolution. in our study, we identified a recombination event in the e protein bagv. recombination was documented in other members of the mosquito-borne flavivirus group [ , ] , but had not yet been demonstrated to occur in bagv. identification of recombination breakpoints and the graphical detection of conflicting phylogenetic signals gave confirmation of this recombination event in e protein of the senegalese isolate ard _dakar-bango_sen_ as previously described for zikv [ , ] . nevertheless, the precise molecular mechanisms of the template switches are unknown. the e protein is highly important because it encodes the most important antigen with regards to virus biology and humoral immunity. therefore, large-scale genetic changes in this region, as might be brought about by recombination, could have significant impact on virus phenotype [ ] . the estimation of the selection pressures acting on each protein of bagv demonstrated episodes of strong negative selection in functionally important proteins. these results suggested frequent purging of deleterious polymorphisms in the bagv genome that could be associated with accumulation of synonymous mutations during bagv transmission [ ] . however, location of more significant episodes of positive selection in the e, ns and ns proteins indicated that they could represent preferential selection targets during bagv evolution [ ] . indeed, the e protein of flaviviruses plays a crucial role in early steps of host cell binding and viral entry and represents a main target for immune responses influencing antigenic response and positive selection on the e protein is a hallmark of the emergence of flaviviruses [ , ] . positive selection episodes have been also previously reported for the denv- capsid, however, the impact needs to be further investigated [ ] . likewise, non-structural proteins could also be targets of positive selection. the ns protein is essential for viral rna replication, is involved in immune system evasion, and represents the major positive selection target during speciation of arthropod-born flaviviruses such as denv and zikv [ ] . ns a and ns b proteins have been shown to antagonize the interferon response during denv infection [ ] and changes in these regions would be evolutionary advantageous selecting for bagv strains with strong innate immunity suppression mechanisms. mutations in the ns b protein were also seen to modulate several phenotype mechanisms of flaviviruses, such as pathogenesis [ ] , viral adaptation [ ] , replication [ ] , neurovirulence [ ] and host preferences [ ] . thus, presence of positively selected sites in ns b of bagv isolates could have major impact in its natural evolution. ns and ns proteins are crucial for viral replication, since non-conservative changes in these regions could modify process of protease and atpase/helicase functions of ns protein [ ] and rna polymerase activity of ns protein [ ] . these several polymorphic amino acid coding sites in the bagv genome suggest that these proteins may be experiencing relatively adaptive changes in the natural evolution and they should be prioritized in future experimental studies. despite the evidence of a single phylogenetic group for bagv sequences analyzed in our study, the evolutionary rates are expected in accordance to proteins functions; the ns representing the polymerase and the most conserved protein [ ] . the inferred bayesian mcc trees indicated a single introduction of bagv into europe and africa from india, contrary to other african flaviviruses as wnv [ ] and zikv [ ] , suggesting an indian origin of bagv. estimated times from the mrca suggested a distant origin of west african bagv sequences analyzed in this study from the th century. thus, further phylodynamic analyzes based on more complete sequences could be interesting for determining geographical pathways and potential evolution patterns in correlation with bagv spread from india to african and european continents. the codon adaptation index (cai) represents a reliable bio-informatics approach to measure the synonymous codon usage bias and to assess the adaptation of viral genes to their hosts [ ] . flaviviruses can infect and replicate in hosts of different phyla. therefore, their versatility in gene expression and protein synthesis and changes in the viral rna genome could affect the fitness of the virus in a specific host relating to dinucleotide frequencies, codon preferences, and codon pair biases [ ] [ ] [ ] . nevertheless, ecology, different virus-host relationships, biogeographical migrations of flavivirus species and genetic differences may explain observed differences in flaviviral codon usage preference to human housekeeping genes [ , , ] . in particular, nkv flaviviruses were only isolated from vertebrates and are maintained in nature by horizontal transmission between vertebrate hosts [ , ] . although isfs were thought to sustain their populations in their respective insect vectors in the absence of mammal reservoirs, so lower translational efficiency in vertebrates could be expected [ , ] . in addition, the highest cais of yfv and denv could be related to their long histories of infection in humans [ ] . indeed, yfv and denv are maintained in endemic and sylvatic cycles, which conducted to repeated epidemics for more than one hundred years. however, yfv showed generally a higher virulence in human infections, particularly when it is compared to denv infections reported in africa [ ] . this could explain the higher cai values of yfv towards codon usage of the human housekeeping genes. with evidence of adaptation to human house-keeping genes, bagv could be potential cause of infection in vertebrates, such as humans. considering the highest cai values of west african bagv isolates when compared to isolates responsible of the spanish wild bird's outbreak in [ ] , bagv adaptation to vertebrate species such as birds could have led to an extension of adaptation to other species as shown in a previous virus study [ ] . interestingly, west african bagv isolates showed a higher evidence of codon adaptation than mbfvs well known to infect humans, such as wnv which is a major cause of human encephalitis in usa and responsible of recent outbreaks in europe [ ] and zikv associated with microcephaly in fetuses and newborns during the outbreak in brazil in [ ] . thus, further comparison of codon adaptation indexes of other bagv genomic regions, such as the utr, among isolates that differ in biological, ecological, and genetic characteristics could help to characterize the evolutionary adaptation of bagv genomes to vertebrate hosts [ , ] . nevertheless, to ensure the potential of bagv to be involved in human encephalitis cases, it would be important to evaluate its pathogenicity on human induced pluripotent stem cell lines (ipsc) capable of differentiating into brain microvascular endothelial cells (bmecs) and constituting a robust model of the human blood-brain barrier [ ] . otherwise, the ipsc cells can also generate primitive neural stem cells (nscs), which can differentiate into neurons, astrocytes, or oligodendrocytes [ ] . these bagv sequences data obtained in our study could be used not only in future viral studies, but also in development of reverse genetic reagents or reliable diagnostic tools for investigation of this virus in human populations. the following are available online at http://www.mdpi.com/ - / / / /s , figure s : sequences of conserved structural rna domains identified on the utr of bagaza genomes used in this study. bag) strain: dak ar b full-length sequencing and genomic characterization of bagaza, kedougou, and zika viruses mosquito vectors of the - outbreak of rift valley fever and other arboviruses (bagaza, sanar, wesselsbron and west nile) in mauritania and senegal isolations of west nile and bagaza viruses from mosquitoes (diptera: culicidae) in central senegal (ferlo) arbovirus isolations from mosquitoes collected during in the senegal river basin genetic characterization of bagaza virus (bagv) isolated in india and evidence of anti-bagv antibodies in sera 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practice: scientific or african traditional research methods? date: - - journal: acta tropica doi: . /j.actatropica. . . sha: doc_id: cord_uid: pl ditn abstract the disease burden in africa, which is relatively very large compared with developed countries, has been attributed to various factors that include poverty, food shortages, inadequate access to health care and unaffordability of western medicines to the majority of african populations. although for ‘old diseases’ knowledge about the right african traditional medicines to treat or cure the diseases has been passed from generation to generation, knowledge about traditional medicines to treat newly emerging diseases has to be generated in one way or another. in addition, the existing traditional medicines have to be continuously improved, which is also the case with western scientific medicines. whereas one school of thought supports the idea of improving medicines, be they traditional or western, through scientific research, an opposing school of thought argues that subjecting african traditional medicines to scientific research would be tantamount to some form of colonization and imperialism. this paper argues that continuing to use african traditional medicines for old and new diseases without making concerted efforts to improve their efficacy and safety is unethical since the disease burden affecting africa may continue to rise in spite of the availability and accessibility of the traditional medicines. most importantly, the paper commends efforts being made in some african countries to improve african traditional medicine through a combination of different mechanisms that include the controversial approach of scientific research on traditional medicines. traditional medicine (tm) is found virtually on all continents where it has been practiced for many centuries. in most developing countries tm is easily accessible and affordable to the larger proportion of the populations relative to western medicine (wm). in africa, it is estimated that about % of the populations rely on tm for their primary health care needs (who, ) . in the developed world tm is used by a relatively smaller proportion of the populations than the proportion that relies on wm. consequently, in the developed countries tm is referred to as "complementary" or "alternative" medicine (cam) since it complements wm which is accessed by a larger proportion of the populations. according to the world health organisation (who, ) , "traditional medicine refers to health practices, approaches, knowledge and beliefs incorporating plant, animal and mineral based medicines, spiritual therapies, manual techniques and exercises, applied singularly or in combination to treat, diagnose and prevent illnesses or maintain well-being." * tel.: + ; fax: + . e-mail address: anyika@amanet-trust.org. one major characteristic of african traditional medicine (atm) is that it has spiritual and non-spiritual components (jolles and jolles, ) . the non-spiritual component is generally referred to as herbalism. it should be made very clear that this paper is not discussing the spiritual component of atm that involves divine healing based on religious faith which is believed to involve supernatural spiritual powers. however, in most cases in practice there is lack of clarity as to whether a traditional healer is practicing as a herbalist or as a divine healer. it is such ambiguity that tends to shroud the practice of atm with so much sacredness that any attempt to question anything associated with the practice is perceived by some people not only as a taboo but also as one of the manifestations of neocolonialism. a paper that touched on some ethical and regulatory issues surrounding african tm in the context of hiv/aids (nyika, ) stimulated some debate in the public domain (knapp van bogaert, ; tangwa, ) . according to tangwa, ethical principles that emanated from atrocities committed by western medical practitioners should not be used to assess whether some actions of african traditional practitioners are right or wrong because they did not take part in the atrocities (tangwa, ) . the current paper, which focuses on atm, will address the issue of whether or not the african traditional healers conduct any research, be it scientific or 'african traditional', before they come up with new treatments. if they do, then there are ethical requirements pertaining to conduction of research in patients which should be met (cioms, ; world medical association (wma) declaration of helsinki, ) . two case studies that capture research approaches that were used during edward jenner's era in western medicine and approaches that are currently being used by some african traditional healers will be discussed. the aim is to highlight firstly the need for properly designed research to improve both traditional and western medicines and secondly, to flag some ethical issues surrounding the practice of and 'research' in atm. the case studies illustrate the fact that research methods that were considered acceptable centuries of years ago should always be reviewed and improved as part of efforts to enhance protection of the well being of patients in particular and mankind in general. . . case study : discovery of vaccination by edward jenner when edward jenner tested the concept of using cowpox virus as a vaccine against small pox, he used a small boy, james phipps, as an experimental subject (http://en.wikipedia. org/wiki/edward jenner). there was a serious outbreak of measles, and as a medical practitioner whose duty was to save human lives, he used his observation that milk maids exposed to cowpox virus were less susceptible to infection with small pox virus as the rationale for testing cowpox virus in the small boy. edward jenner used his experience and knowledge in his capacity as a medical practitioner and demonstrated the concept of vaccination. he became very famous and globally, vaccines have contributed towards successful control of many diseases such as measles and polio. however, research methodologies for the development of vaccines have since evolved and the approach used by jenner is now considered to be poor scientific design and unethical. instead of one person conducting the research, multidisciplinary research teams conduct research so as to minimize the risks of bias and errors in the research process as well as in the analysis of collected data. in addition, a research protocol has to undergo review to ensure minimum acceptable scientific and ethical standards before the research starts. . . case study : discovery of hiv/aids treatment and cure by a traditional healer a well-known, highly respected african traditional healer used to treat many patients suffering from a variety of illnesses. when the hiv/aids pandemic started affecting his country, he also started 'diagnosing' hiv infection in some of his patients. using his knowledge and experience as a traditional healer, he tried some of his traditional medicines on his hiv/aids patients but without informing them that the medicines were being tested. after the 'trials', the healer was convinced that the medicines were effective not only for treating but curing hiv/aids patients. since his medicines were very affordable compared with the western medicines, he soon became the first port of call for many patients seeking treatment and cure for hiv/aids. he became a very rich and famous person in his country and in neighbouring countries. however, the traditional healer was totally against the idea of subjecting his medicines for hiv/aids to any form of tests involving other stakeholders and insisted that his observations and deductions were sufficient to guarantee safety and efficacy. the traditional healer and those who shared his view argued that scientists and pharmaceutical companies wanted to hijack the traditional knowledge for their own commercial benefits. on the other hand, people calling for properly designed scientific research to be conducted on the traditional medicines argued that if the traditional medicines that were being claimed to treat or cure hiv/aids were truly effective, the ever rising disease burden and mortalities due to hiv/aids in africa would have been brought under control since the traditional medicines were widely accessible to those who needed them. most importantly, they argued that the risk of bias in the observations and deductions made by the healer who would benefit from payments by patients was unacceptably high. . . western medical practice and research: from edward jenner type of research to randomised controlled trials case study captures research methodology that was used ages ago, and was acceptable then but is no longer acceptable nowadays. today, a single medical doctor may not simply decide to test something in a patient or in patients without involving other people with relevant expertise that the doctor may not have. there is now a requirement that any testing of anything in human beings should be explained in a protocol in order to enable peer review (cioms, guideline ; world medical association (wma) declaration of helsinki, ) . the review of the protocol is meant to ensure that firstly there are no flaws in the planned methodology that may compromise the usefulness of the findings and secondly that the safety of the humans who will take part will not be compromised. the most important requirement for research nowadays is the informed consent. many international and national ethical guidelines or legal frameworks clearly stipulate that obtaining informed consent is a prerequisite for research. for instance, the cioms guideline states that "for all biomedical research involving humans the investigator must obtain the voluntary informed consent of the prospective subject or, in the case of an individual who is not capable of giving informed consent, the permission of a legally authorized representative in accordance with applicable law. waiver of informed consent is to be regarded as uncommon and exceptional, and must in all cases be approved by an ethical review committee (cioms, ) ." thus when a patient presents to a medical doctor seeking treatment and the doctor happens to be involved in a study that is testing an alternative treatment, the doctor must inform the patient so that s/he decides whether to take part in the study or not. the patient may decide not to take part in the study but should still be given the standard treatment. if there is no proven standard treatment for the disease, then the doctor has to explain to the patient that the medicine available is still being tested. that is the distinction between medical practice and research. indeed, both the treatment and research may be done in the same hospital settings, but the patients must be informed if they are to be used in a study. edward jenner conducted his experiment alone, which during his era was most probably acceptable to the communities, the medical fraternity and perhaps to the parents of james phipps for medical practitioners to use their discretion to conduct 'research' as they saw fit without any peer review. it was fortunate that edward jenner's observations and deductions happened to be correct and that his 'experiment' yielded positive results without serious adverse reactions. but nobody knows whether or not he had conducted other 'experiments' detrimental to the health of his research subjects. nowadays it is no longer acceptable, no matter how knowledgeable the medical doctor is, to conduct such tests using people without voluntary informed consent. we are in a new era in which people should be adequately informed to enable them to make informed decisions. precautions should always be taken to safeguard the welfare of patients or research participants, and also to be sure that the research methodology is such that the research questions can be answered objectively and accurately. it should be acknowledged that atm has evolved over centuries of years, and has involved systematic methods of assessing medicinal or detrimental properties of herbs. although one school of thought may want to refer to that systematic assessment of traditional herbs as 'african traditional research methods', it could be argued that the systematic approach was basically scientific, more or less similar to the approach that jenner used, and was devised by the african traditional healers themselves. for instance, one approach used by the traditional healers long time ago was to observe herbs that were never eaten at all by animals, and such herbs were suspected to be poisonous and would be avoided by the traditional healers. long time ago there were no means of testing toxicity; hence such an approach was logical during that era. the point is that centuries of years ago african traditional healers developed methods of assessing safety and medicinal properties of herbs that were logical and acceptable during that era, but the methods should change with time. traditional knowledge was therefore not gathered haphazardly, there were systematic ways of gathering the knowledge which was then passed from one generation to the next. was this approach of gathering knowledge not scientific research methodology that was acceptable during that era, just like jenner's approach? if it was not scientific but an african research methodology, should it remain the same as it was ages ago even when circumstances are changing and the diseases affecting africa are dynamic? just as there were limitations in the research methodologies used by jenner, the research methodologies used by traditional healers had limitations which should be gradually overcome as time goes by. in other words, the research approaches used by traditional healers should be dynamic, the aim being to continuously improve and overcome limitations. in contrast to case study which depicts what used to happen ages ago in the context of wm, case study shows what is still happening today in the context of atm. in the advent of the hiv/aids pandemic, the african traditional healer in case study tried some of his medicines in patients and came to the conclusion that his medicines were effective. the implication is that there was some form of research that involved testing of the traditional medicines for hiv/aids, albeit without disclosure of such 'research' activities to the patients. the traditional medicines that were being given to people living with hiv/aids were not free of charge; the traditional healer benefited financially from the sale of the medicines. it therefore means that there was conflict of interest since the traditional healer testing the medicines was the one who interpreted the findings and eventually benefited financially from the sale of the medicines. although the medicines were affordable to the majority of the people needing them, the high prevalence of hiv/aids in most african countries meant that there were large numbers of people needing such medicines, which translated into huge financial gains for the healer relative to ordinary members of the community. another point to be highlighted is that when the traditional medicines are being tested, the patients are not informed about the testing aspects. it is important that any necessary procedural differences in the process of obtaining informed consent are allowed in order to respect different cultural and traditional practices. for instance, empirical studies conducted in some developing countries showed that most people prefer to discuss with their spouses or relatives before deciding whether or not to take part in health research (decosta et al., ; nyika et al., ) . thus obtaining informed consent should not be an event, but a process that allows ample time for consultations as per the wishes of the prospective participants. another issue is that patients have to buy the traditional medicines even if they are still being 'tested' and may have side effects. there is need to assess potential side effects, and such assessments may require laboratory tests in addition to clinical assessments that the traditional healers may perform. it is therefore critical that medical practice, be it traditional or western, is clearly distinguished from medical research, especially when medical practitioners play both roles as service providers and researchers. it also means that there should be well thought out plans of how the research would be done, instead of anecdotal ways of testing medicines, be they western or traditional. most importantly, the experimental people should be informed that the medicines are being tested in them. since no person is omniscient, there may be need to include people with expertise in various relevant fields in the research team. instead of having a one-man research project, like the one edward jenner or the traditional healer conducted, bringing on board other experts such as epidemiologists, microbiologists, statisticians, pharmacists, physicians and people experienced in conducting clinical trials could significantly increase the quality of research. the ultimate goal of health care systems is to reduce the burden of diseases and improve the quality of life. thus it negates the purpose of having health care if availability and affordability of the health care do not effectively contribute towards the achievement of good health of people and reduced disease burden. it would be unethical to focus only on availability and affordability of african traditional medicines to the poor african populations relying on the medicines without assessing whether or not the disease burden of the populations is being reduced. it should be acknowledged that there are other factors such as poverty, poor nutrition and environmental factors that affect disease burden. however, if some african traditional medicines and some western medicines can make positive impact even in the presence of such factors, then the aim should be to improve the medicines so that they can make as much impact as possible. the question that should be asked is whether or not the access to african traditional medicines by the estimated % of the african populations is effectively tackling the disease burden of the populations. in the advent of emerging and re-emerging diseases, it is imperative that atm keeps improving in order to rise up to the new challenges. organizations such as the cdc have realized the need for public health systems to be ready for such diseases and are always working on prevention strategies in light of environmental, societal and technological factors (centers for disease control and prevention (cdc), ). examples of emerging diseases are hiv/aids, ebola, severe acute respiratory syndrome (sars), multidrug resistant tuberculosis (mdrtb) and extreme drug resistant tuberculosis (xdr tb). examples of re-emerging diseases include plague caused by yersinia pestis, cholera caused by vibrio cholerae and dengue hemorrhagic fever caused by flaviruses. as is the case with western medicines, research is needed to better understand potentially harmful side effects that may be associated with some traditional medicines. it should be emphasized that harms are not always caused deliberately; they may be caused inadvertently. hence the need for checks and balances to minimize potential harms. in cases where crude mixtures of traditional medicines are used, the possibility of identifying and separating active components from other non-therapeutic components which may have harmful side effects should be explored. it means therefore that existing traditional medicines should be improved and new ones should be developed in order to match the dynamics in the disease burden of the global population. african traditional medicine should reach a stage where it competes with the western medicines, thus becoming a source of revenue for countries that are bestowed with such valuable natural resources. such competitiveness could go a long way in lowering the costs of drugs and making effective health care accessible to poor communities. africa should not bemoan the unavailability or unaffordability of western medicines developed by pharmaceutical companies when african traditional medicines are abundantly available and accessible to the african populations to the extent that it has been proposed that atm should be considered the 'orthodox/conventional' medicine for africa (tangwa, ) . for instance, hiv/aids affects africa more than other continents in terms of deaths and prevalence; this is in spite of the availability of affordable traditional medicines in africa. instead of scrutinizing the effectiveness of the abundantly accessible african traditional medicines, unavailability or unaffordability of western medicines are sometimes blamed for the high prevalence and mortality rates prevailing in africa. it follows therefore that there is need for research in order to improve the efficacy of the african traditional medicines. if there are african 'traditional' research methods that are different from scientific methods of research but can improve the efficacy of the traditional medicines, then such methods should be used. what is important is to develop safe and effective medicines, and any method that is appropriate and effective should be used, provided people who participate in the process are informed. it could be argued that scientific research methods are the most effective, if the impact arguably being made by medicines developed by pharmaceutical companies is anything to go by. the involvement of such organizations as the world health organization (who) and the african union (au) in promoting scientific research into atm has enhanced conduction of various types of scientific studies aimed at improving the safety, efficacy and quality of traditional medicines (aachrd, ) . consequently, several african countries are intensifying efforts to improve traditional medicines through scientific research. for instance, laboratory analyses have been done in who-supported scientific studies conducted on traditional medicines intended for treatment of hiv/aids in burkina faso and zimbabwe (aachrd, ) . the laboratory analyses done include cd /cd counts and viral load measurements to assess efficacy as well as liver and kidney function tests to assess potential side effects of the medicines. in addition, in ghana, kenya and nigeria who has sponsored pilot clinical trials to test the efficacy of traditional medicines used to treat malaria. the control arms in the pilot trials were treated with chloroquine or fansidar for comparison (aachrd, ) . the clinical trials of the traditional medicines are being conducted by african scientists based at institutions in african countries. it should be pointed out that informed consent is obtained from people who participate in the scientific studies testing the traditional medicines, which should always be done when anything is being tested in humans. in an effort to regulate, promote, develop or standardize the practice of atm, some african countries are reviewing existing legal frameworks or putting in place news ones (who, ) . for instance, the south african parliament recently passed the traditional health practitioners act, no (traditional health practitioners act, ) . there are also efforts in various african countries such as south africa to promote collaboration between traditional healers and biomedical researchers (south african medical association task team, ) , which could go a long way in enhancing ethical and scientific standards and sharing of knowledge. if a traditional healer is not sure of the efficacy of the herbs s/he wants to try/test on a patient, but believes for one reason or another that it should work, patients should be informed about the uncertainty. informing the person whose body is to be exposed to the 'experimental' traditional medicine, which in most cases is not for free but is paid for, that the medicine is being tested demonstrates respect for the person. whether we want to call the 'testing' of the traditional medicines in patients 'research', and the disclosure of such 'testing' informed consent or something else is a matter of semantics. the fact of the matter is that a patient or customer should be given such information in order to make an informed decision. when african traditional medicines are being tested in clinical trials, the participants are informed and they give informed consent; the same should be done when the traditional medicines are being tested by african traditional healers. if it is unethical for 'western' medical practitioners to conduct the edward jenner type of 'testing' (which was poorly designed research) in patients, it follows that it is also unethical for traditional medical practitioners to conduct the same edward jenner-type of 'testing' (which is similarly poorly designed research) in their patients without first obtaining their informed consent. if such an action is considered ethically and morally wrong when the moral agent is a 'western' medical practitioner and the patient is a poor, desperate african person, it should not be considered ethically and morally right when the moral agent is an african traditional medical practitioner and the patient is the same poor desperate person. if the 'western' medical practitioner was to secretly test the african traditional medicines in the poor desperate african patients without their informed consent would it be considered to be ethically and morally right? the fact that most of the ethical codes and guidelines being used nationally and internationally were a result of human abuses committed by scientists in western countries does not make them completely irrelevant to atm in africa. one argument put forward is that "african tm was not an accomplice in, let alone the one responsible for, the medical atrocities that resulted in the nuremberg trials and the nuremberg code" (tangwa, ) . do we need to first have an african version of the nazi atrocities so that we can then develop african versions of the nuremberg code and african versions of all the subsequent ethical codes and guidelines? is some form of disaster a prerequisite for existing mechanisms of protecting the clientele of african traditional healers to be strengthened and/or new ones to be put in place? is it ethical and logical to require that humans should be harmed by atm first, in large numbers like in the nazi atrocities, before precautions could be taken or enhanced? would that be an objective, proactive and ethical way of protecting human beings? are the ethical and moral principles on which the 'western' codes and guidelines are based different from the ethical and moral values that prevail in the african communities that rely mainly on atm? such african ethical and moral values may not be written or given the same terms as the western codes, but they are practiced in the day-to-day lives of the communities. the ethical principles of autonomy, beneficence, non-maleficence and justice have been practiced in the african communities in the absence of the ter-minology that was eventually coined by the west. what then is wrong if the same principles and guidelines are used to assess the actions of african traditional healers as they practice or test their medicines either to improve efficacy or to tackle new diseases? the paucity of documented harms caused by atm does not necessarily mean that such harms never occur. the global trade in traditional medicines is increasing in both developing and developed countries. for instance, us$ billion was spent on cam in in the usa alone, with the global market for herbal medicines being over us$ billion (who, ) . thus traditional medicines are natural resources which could be developed to a level that significantly complements exports that generate the much needed foreign currency for most developing countries. the ultimate goal should be to have the improved african traditional medicines developed and manufactured in the developing countries so as to export them as finished products. efforts to develop african traditional medicines into value-added medical products are being intensified in some african countries. for instance, a pharmaceutical company in south africa has developed a local traditional medicinal herb called sunderlandia into standardized tablets (aachrd, ) . in nigeria two traditional medicines, dopravil and conavil, that local traditional healers claim to be effective for the management of hiv/aids have been standardized and have reached clinical trial phase ii (aachrd, ) . the developing countries stand to benefit to some extent from employment created by such endeavours to develop traditional medicines. in addition, there could be significant financial savings due to reduced imports of medicines from developed countries. the challenge to protect the owners of traditional knowledge, who may not be adequately protected by the existing current intellectual property rights (ipr) frameworks, has been pointed out (timmermans, ; nyika, ) , and there is need to review or expand the current ipr policies in order to address the peculiar nature of traditional knowledge. the majority of the african populations rely on atm because it is easily accessible and is affordable. this fact makes the need to ensure that atm is made as effective and as safe as possible urgent because of the large numbers of people who make use of it in the wake of high disease burden. efforts to improve atm should not be perceived as evidence of condemnation of the practice of atm or as neocolonialism because dynamics in the disease patterns and socioeconomic status of the global populations, including african populations, dictate that atm has to respond to the changes in order to effectively serve the purpose for which it has been developed. the ultimate goal should always be to make various complementary efforts that are ethical and are aimed at reducing the disease burden in african countries. the efficacy and safety of african traditional medicines could be enhanced through well designed research that is conducted ethically in africa. any methods, be they african, western, chinese, or any other, that are capable of further improving the safety and efficacy of the african traditional medicines should be used as a matter of urgency because diseases are wrecking havoc in africa in spite of the accessibility and affordability of the african traditional medicines in their current state. if it so happens that scientific methods are the most effective in terms of improving the safety and efficacy of medicinal products, be they african or western, then let african scientists and traditional healers use the scientific methods to improve the african traditional medicines. what is the point of african govern-ments investing a lot of resources in educating africans in sciences and then consider use of scientific research to develop african traditional medicines to be unacceptable? however, whatever methods are used to develop the african traditional medicines, patients should be informed that research is going on and secondly ways of protecting the custodians of the traditional knowledge should be put in place. when the actions of scientists are subjected to scrutiny, it is not because scientists are all evil people whose aim is to deliberately harm patients or research participants. similarly, scrutiny of african traditional healers should not be viewed as condemnation of the practice of atm in its entirety. whereas it is to a reasonable extent possible to distinguish between practice and research in western medicine, it is generally not very clear in the context of african traditional medicine. if african traditional medicines are being tested in humans, the traditional healers should inform the patients that the traditional medicines are being tested for effectiveness against the diseases that the patients are suffering from. that is respect for the patients who have a right to know that they are in a study to test some traditional medicines. african advisory committee for health research and development (aachrd) preventing emerging infectious diseases: a strategy for the st century international ethical guidelines for biomedical research involving human subjects community based trials and informed consent in rural north india zulu ritual immunisation in perspective ethical consideration in african traditional medicine: a response to nyika ethical and regulatory issues surrounding african traditional medicine in the context of hiv the effect of relationships on decisionmaking process of women in harare bridging the gap: potential for a health care partnership between african traditional healers and biomedical personnel in south africa how not to compare western scientific medicine with african traditional medicine intellectual property rights and traditional medicines: policy dilemmas at the interface republic of south africa legal status of traditional medicine and complementary/alternative medicine: a worldwide view traditional medicine fact sheet number ethical principles for medical research involving human subjects i am grateful to the bill and melinda gates foundation for grant id # awarded to amanet for building institutional capacities in health research ethics in africa. amanet also receives major support from the danish development agency (danida), the european commission (dg-research and aidco), the netherlands ministry of international cooperation (dgis), the european developing countries clinical trials partnership (edctp), and the african caribbean pacific secretariat for various project activities. key: cord- -rjuug er authors: umviligihozo, gisele; mupfumi, lucy; sonela, nelson; naicker, delon; obuku, ekwaro a.; koofhethile, catherine; mogashoa, tuelo; kapaata, anne; ombati, geoffrey; michelo, clive m.; makobu, kimani; todowede, olamide; balinda, sheila n. title: sub-saharan africa preparedness and response to the covid- pandemic: a perspective of early career african scientists date: - - journal: wellcome open res doi: . /wellcomeopenres. . sha: doc_id: cord_uid: rjuug er emerging highly transmissible viral infections such as sars-cov- pose a significant global threat to human health and the economy. since its first appearance in december in the city of wuhan, hubei province, china, sars-cov- infection has quickly spread across the globe, with the first case reported on the african continent, in egypt on february (th), . although the global number of covid- infections has increased exponentially since the beginning of the pandemic, the number of new infections and deaths recorded in african countries have been relatively modest, suggesting slower transmission dynamics of the virus on the continent, a lower case fatality rate, or simply a lack of testing or reliable data. notably, there is no significant increase in unexplained pneumonias or deaths on the continent which could possibly indicate the effectiveness of interventions introduced by several african governments. however, there has not yet been a comprehensive assessment of sub-saharan africa’s (ssa) preparedness and response to the covid- pandemic that may have contributed to prevent an uncontrolled outbreak so far. as a group of early career scientists and the next generation of african scientific leaders with experience of working in medical and diverse health research fields in both ssa and resource-rich countries, we present a unique perspective on the current public health interventions to fight covid- in africa. our perspective is based on extensive review of the available scientific publications, official technical reports and announcements released by governmental and non-governmental health organizations as well as from our personal experiences as workers on the covid- battlefield in ssa. we documented public health interventions implemented in seven ssa countries including uganda, kenya, rwanda, cameroon, zambia, south africa and botswana, the existing gaps and the important components of disease control that may strengthen ssa response to future outbreaks. transmission dynamics of the virus on the continent, a lower case fatality rate, or simply a lack of testing or reliable data. notably, there is no significant increase in unexplained pneumonias or deaths on the continent which could possibly indicate the effectiveness of interventions introduced by several african governments. however, there has not yet been a comprehensive assessment of sub-saharan africa's (ssa) preparedness and response to the covid- pandemic that may have contributed to prevent an uncontrolled outbreak so far. as a group of early career scientists and the next generation of african scientific leaders with experience of working in medical and diverse health research fields in both ssa and resource-rich countries, we present a unique perspective on the current public health interventions to fight covid- in africa. our perspective is based on extensive review of the available scientific publications, official technical reports and announcements released by governmental and non-governmental health organizations as well as from our personal experiences as workers on the covid- battlefield in ssa. we documented public health interventions implemented in seven ssa countries including uganda, kenya, rwanda, cameroon, zambia, south africa and botswana, the existing gaps and the important components of disease control that may strengthen ssa response to future outbreaks. jul report report the views expressed in this article are those of the author(s) and do not reflect those of their employers or institutions. publication in wellcome open research does not imply endorsement by wellcome. covid- is caused by a novel beta-coronavirus named severe acute respiratory syndrome coronavirus (sars-cov- ) that was first reported in december in the city of wuhan, hubei province, china . sars-cov- infection has quickly spread across the globe , with the first case reported on the african continent, in egypt on february th . covid- was declared a public health emergency of international concern by the world health organization (who) on march th . just a few months into the pandemic, covid- has ravaged developed countries, with significant case fatality rates in europe and the usa . considering the large number of people that live in poor and crowded informal settings in sub-saharan africa (ssa) , , the mode of transmission of sars-cov- , the severity of the disease as well as the existing fragile health systems [ ] [ ] [ ] it was hypothesized that africa may markedly be affected by the covid- pandemic resulting in disastrous consequences with a large number of patients overwhelming hospitals and high case fatality rates , . as of june th covid- global infections recorded in countries were and only one of these countries is located in the ssa region. although the global number of sars-cov- infections increased exponentially since the beginning of the pandemic due to ongoing transmission, the low number of infections and deaths recorded in ssa countries have raised suspicions on whether they represent a slow progression of the pandemic in africa, a lower case fatality rate, or simply a lack of testing or reliable data. notably, there is no significant increase in unexplained pneumonias or deaths recorded on the continent which could possibly indicate the effectiveness of interventions introduced by several african governments. however, there has not yet been a comprehensive assessment of ssa's preparedness and response to the covid- pandemic that may have contributed to prevent an uncontrolled outbreak so far. here, we -a diverse group of early career researchers (graduate students and post-doctoral scientists) and the next generation of african scientific leaders with experience working in various fields of health research including medicine, immunology, molecular biology, microbiology, virology and public health in both ssa countries and in developed countries -conducted an assessment of african preparedness and response to the covid- during the early (first months) of the pandemic on the african continent. the early career researchers involved are fellows of the african academy of science's sub-saharan african network for tb/hiv research excellence (santhe) , (part of the deltas africa initiative) and some were at the frontline of the battle against covid- in their respective countries during the time of this assessment. as of june th , the seven countries represented had reported the following caseloads of covid . even though the covid- pandemic unfolded rapidly, and the undertaken public health measures interrupted our studies, our careers and other usual activities, this pandemic has also offered a blueprint on how to deal with epidemics. this analysis presents a unique perspective on the currently developed public health interventions to fight covid- on the african continent. we discuss the challenges and opportunities that exist to improve african capacity to fight future epidemics from our perspective as the next generation of scientists that will oversee these responses in the future. our evaluation of sub-saharan africa preparedness and response to covid- reviewed country specific preventive measures and critically examined the response to the pandemic in seven african countries. we assessed the public health measures and other crucial interventions that were put in place in the control of covid- in uganda, kenya, rwanda, cameroon, zambia, south africa and botswana. we argue that these strategies may have helped to prevent a disastrous outcome by reducing rapid transmissions that may happen in clusters and minimizing the number of patients seeking medical assistance at the same time. we also identified and summarized in three categories of biomedical, sociocultural and economic factors; the challenges encountered at different levels of the health system. we presented the gaps existing in the public health intervention programs that may result in delays/failure to halt the spread of the disease as well as the important components of disease control that may strengthen sub-saharan africa preparedness and response to future outbreaks. the rapid rise of sars-cov- infections sent a clear message to the world that quick action was needed to prevent the spread of the disease. who warned on february nd that all member states of the african union should develop an early strong plan of action to tackle the growing threat . as emerging africa leaders in health research and fellows of the santhe consortium, we convened a virtual meeting to discuss the threat that the pandemic posed to ssa and agreed that we had a responsibility to critically analyze the response of our governments so far and to offer our own perspective on how this and other similar epidemics should be tackled on the continent. in the meeting, participants discussed the origin of the new sars-cov- virus, infection preventive measures, diagnostic tests, clinical management of the disease and the development of vaccines and therapeutics by critically reviewing the available scientific literature. we discussed the need for scientific and evidence-based responses that considered africa's unique healthcare, sociocultural and economic challenges. we therefore decided to review sars-cov- infection dynamics in africa and the responses that african governments were taking, relying primarily on published scientific articles, publicly available government technical reports, media announcements and our own personal experiences and perspectives. considering that the response to the epidemic has been very variable from country to country, we agreed to focus our analysis from reports emanating from uganda, kenya, rwanda, cameroon, zambia, south africa and botswana, countries that were represented among us. an extensive review of the steps taken in preparedness and response to covid- guided by a representative from each of the seven ssa countries was conducted and a conclusive report encompassing our perspectives was generated. since the beginning of the covid- pandemic, the world's top priority was to contain the spread of sars-cov- , to reduce disease fatalities and to limit the patient burden on health systems. despite the uncertainty and unanswered questions around the management of the newly emergent sars-cov- infection, african countries joined the global effort to battle the covid- pandemic as we outline in detail below. it has been reported that the experiences of ssa countries in handling ongoing outbreaks and managing infectious diseases such as ebola, tuberculosis, malaria and hiv came in handy in the fight of covid- - . pre-existing emergency plans on public health interventions, community engagement programs and the work force composed of emergency medical experts and trained health care workers were quickly re-directed to ensure a fast response to covid- - . as early as january , prior to the identification of the first case of sars-cov- infection on the african continent on february th the majority of african countries lack specialized medical capacity that is critical for handling severe cases of covid- , such as intensive care unit (icu) beds , and mechanical ventilators . therefore, the main priority on the african continent was to contain the infection, initiate immediate testing for suspected cases and to start medical intervention prior to development or progression to severe clinical disease. the countries we assessed focused their efforts on prevention, early identification of new infections and mitigating mass spread of the virus by quickly tracing case contacts based on the available information. all seven countries initiated border screening at ports of entry by march and a -day self-quarantine was recommended for all incoming travellers , - . although as a result of few or unavailable laboratory technology, some ssa countries could not test for covid- locally, the early established collaborative model among african countries, coordinated by the africa cdc, increased testing capacity across the continent , , as an example early samples of suspected covid- cases from the central african republic were shipped to rwanda for testing until the local capacity became available. nonetheless, testing constraints still remain in most countries , and therefore testing priority was given to most at risk persons such as returning travellers, or the people who have been in contact with confirmed cases, identified through contact tracing by health care workers. all the seven countries have initiated early testing of suspected cases and established designated facilities for testing and clinical care of covid- patients , - . the early implementation of covid- preventive measures delayed the rapid spread of the virus within the african population, but these procedures could not completely halt the spread of the virus in all seven countries. soon after each country had identified the first case of covid- , new infections were reported, with the majority related to returnee travellers or contacts of index covid- cases. to reduce the risk of imported cases, these countries, with the exception of zambia, swiftly closed borders, shut airports and reduced incoming travellers to essential workers and returning residents , - , - . in order to mitigate further spread of the disease, individuals diagnosed with covid- were admitted in designated isolation areas for care and medical assistance while case contact tracing was immediately initiated. additionally, mass gatherings and non-essential travels were prohibited, government and private business staff were encouraged to work from home and schools were closed , - . with the exception of zambia, the assessed ssa countries implemented a dusk to dawn curfew and nation-wide lockdown to enforce social distancing measures, limiting movements to essential service providers , - . these measures were mainly put in place to prevent large volumes of new infections that would result in a high demand for hospital services, potentially leading to overwhelming of the fragile medical infrastructure , . contrary to what was initially expected, the spread of sars-cov- has been relatively slower in africa , and covid- infections have been generally mild to moderate, leading to more recoveries and lower fatality rates in the seven ssa countries compared to western countries . it should also be mentioned that this pandemic started earlier on the other continents, suggesting that it may be too early for ssa to celebrate its relative success as africa may have not yet faced the highest phase of the disease. however, a comparison of the early phases of the pandemic in some african and european countries has shown a positive impact of early interventions initiated by ssa countries resulting in distinct disease trajectories, for example a comparison of the infection dynamics in the united states, united kingdom, italy and spain vs south africa and cameroon has shown a continual exponential peak in non-african countries but slow and gradual increase in both of the ssa countries . our analysis suggests that early initiation of preventive measures, a faster response by timely testing of suspected cases and immediate contact tracing done by ssa countries has mitigated a faster and more extensive spread of the virus in the population. additionally, a contemporary warm climate may have impacted the dynamics of the sars-cov- transmission in these countries [ ] [ ] [ ] . we posit that the predominantly young demography could be a contributing factor to a mild disease and low case fatality observed in africa , . furthermore, there are suggestions that cross reactive-immunity resulting from previous infections that are predominant in the region or the universal bcg vaccine policy , widely recommended for infants vaccination in the assessed countries, may have offered some health benefits such as enhanced lung cells immunity against infections contributing to better clinical outcome of the disease. however, these observations have not yet been confirmed by rigorous evaluations. altogether, the prevention programs that were put in place and the early response implemented by ssa countries may have mitigated the widespread dissemination of the sars-cov- virus and fatality due to covid- in ssa countries , . the interventions implemented in all seven ssa for prevention and control of the covid- are summarized in table . the mode of transmission of sars-cov- has led to enforcement of social distancing measures by restrictions of mass gatherings and a national lockdown in six of the seven countries that we assessed - , , , - . this method of prevention has specifically disrupted the school programmes and created economic crises that resulted in hunger and other hardships for the large ssa population who depend on casual labor and rely on daily income . the fragile health systems coupled with lockdown measures have inadvertently reduced access to health care for non-emergency and other pre-existing medical conditions. for example with a re-prioritisation of human resources, it is estimated that an additional . million tb cases will occur over the next five years . although the impact on other diseases such as hiv and malaria has not been assessed, it is likely that the covid- pandemic will set back some of the gains made in the countries' responses to these killer diseases. recommended solutions to bridge the gaps for improved outbreak preparedness and response based on our assessment of the challenges and the gaps that were found in the approach used by the seven ssa to prevent/ respond to covid- outbreak, we summarized the potential solutions in figure . we classified these into three interconnected table . summary of interventions implemented for prevention and response to covid- . strengthening medical capacity and testing technology. in collaboration with who, africa cdc and member states the following steps were taken: • january th : africa cdc activated its emergency operations center incident management system (ims) for the n-cov outbreak. • procurement of sars-cov- testing kits • establishment of collaborative model among african countries, setting up a specimen referral system. preparedness and preventive measures (january-march ) all the seven sub-saharan african countries implemented similar responses to covid- except zambia that didn't close borders or enforce a national lockdown. the different interventions and the date the implementation date in each country are presented below: border closure for non-citizen and non-essential workers. (except for zambia) covid- screening at port of entry for all seven countries -dayself-quarantine recommended for all incoming travellers. isolation of covid- patients at designated facilities and close medical monitoring immediate contact tracing and testing. prohibit mass gathering and non-essential travels inside the country recommendation to work from home for private and government institutions dusk to dawn curfew and a national lockdown (except zambia) only screening at the port of entry and self-quarantine were implemented in zambia. a curfew was first implemented in kenya in march th followed by a national lockdown in april th • delayed testing that may result in increased disease spread due to late detection of covid- cases. shortage of medical/research and clinical laboratory personnel and space • overworked medical personnel • focused medical attention to covid- delaying non-essential medical services during the pandemic such as the recommended regular medical check-ups and non-life-threatening interventions. • interruption or delay of non-covid- related medical/research activities (example: minor/elective surgeries). lack of local biotech capacity to conduct advanced biomedical research studies such as transmissibility of sars-cov- in the african climate conditions, antibody-based therapy, or vaccine and treatment research in the african population. • relying on responses from countries that have the capacity to create solutions. • unavailability of accurate information relevant to the local context that is important for development of adequate preventive measures. borders closure and reduced frequency of international trade • delay of transport of essential materials that are initially imported (example shortage of infant vaccines, anesthesia used for minor surgeries or dentistry). • increased cost for medical supplies and imported food items • unavailability of needed materials locally interrupted supply chain due to market scarcity/ priority given to non-african countries • incapacity to obtain suppliers for the african market even when there are available funds. • shortage of frequently used reagents that need to be imported. poor infrastructure, poverty, informal housing and high population density • increased risk to get the infection due to unavailability of essential sanitary services • nearly impossible to comply with social distancing • hardly able implement safety measures reduced job security due to lockdown measures • increased unemployment during covid- pandemic • loss of income for most of the families who depend on casual labor, informal market that have been severely affected by the lockdown. lockdown resulting in reduced movements between cities, unavailability of public transportation and discontinued non-essential work activities including stopping work for researchers working on non covid- projects • interruption of pre-existing programs (ex: hiv prevention programs such as prep, art treatment, tb programs, cancer, maternal health care or non-lifethreatening surgeries), • ironically, the emergence of a new virus has prevented virologists to go to the lab! lack of income due to discontinued earning activities, inability to buy food leading to starvation • countries unplanned mobilization of emergency fund to feed poor families. • early ease of the lockdown that may result in new infections • re-opening work activities to avoid hunger related deaths. categories of biomedical, sociocultural and economic aspects that we recommended to help improve the preparedness and response to future outbreaks. in response to the current covid- pandemic, africa cdc has started planning for the coordination of a centralised procurement system to reach the target of million tests across the continent. tens of thousands of test kits, ppe and thermometers have already been distributed to countries through a donation from the jack ma foundation . however, sustainability of a strong supply chain requires african governments to mobilize resources and to avail funding for health emergency response and research development on the continent including funded education in speciality fields. this will allow the countries to generate adequate interventions and to maintain a rapid response to outbreaks without overreliance on expertise from non-african countries and urgent importation of supplies. ssa countries should leverage novel medical/research capacity upon the existing structures that were put in place over many decades of fighting other public health threats such as ebola, hiv, tb and malaria. the establishment of a network of multidisciplinary health care workers competent in various tasks such as community education and testing, in a multi-disease focused approach would allow management of staff shortage rather than having to prioritize the new life-threatening disease over those that were already prevailing on the continent. some of the limitations encountered during the development of this assessment were mainly related to the lack of sufficient documentation to address the actual reality in ssa countries, such as the status of health systems or informal housing structure. documentation on physical capacity on the african ground is needed. some essential documents lacked the important information such as the date signed and released. improvement on good record keeping especially for health data of this kind is essential for future references. our assessment was not designed to demonstrate with certitude that the implemented interventions were directly linked to the number of infections or covid- deaths in the assessed ssa countries. clinical and biomedical research studies may be more appropriate to confirm these observations. further, systematic reviews of effects would be informative. nevertheless, we believe that our unique perspective on the ssa countries preparedness and response to a great health threat such as the covid- pandemic has provided a valuable contribution to the future interventions. we assessed the sub-saharan africa preparedness and response to covid- . based on an extensive review of the available scientific publications, the government technical reports and the announcements released by governmental and nongovernmental health organizations as well as our personal experiences as workers on the covid- battlefield in ssa countries. we documented the preventive measures and the response put in place to contain the sars-cov- in seven ssa countries including uganda, kenya, rwanda, cameroon, zambia, south africa and botswana. we have shown the strengths of early initiated interventions that may have contributed to modest and slower dynamics of covid- in ssa countries. we discussed the need for scientific and evidence-based responses that considered africa's unique healthcare, sociocultural and economic challenges. while efforts to bridge some of the gaps have been initiated, we recommend that ssa countries develop continued funding streams to support these initiatives as well to increase south to south/north-south collaborations to enhance the capacity of the existing health systems. therefore, if these problems are addressed in a timely manner, there is no doubt that in the next five years ssa countries will have developed a reliable-strong health system to prevent the newly emerging viral infections to spread at a large scale. no data are associated with this article. this is an open letter by umviligihozo et al. that aims at documenting the public health interventions against covid- implemented in seven sub-saharan african countries. overall, the paper is well written and covers the most pertinent issues on the topic. it highlights the diverse implementation strategies employed by the seven ssa countries but notes the relative similar low mortality experienced in ssa. however, the article could do with a bit of balancing of viewpoints, especially discussing why despite the relatively different implementation strategies of pubic health measures the mortality is relatively low but similar among the ssa countries. in countries like malawi (not discussed in the article), that have struggled to implement public health interventions, the mortality has not been very different from the other ssa countries. could this observation mean that it is not necessarily the public health interventions that have driven the low mortality in ssa but potentially other factors? the authors have speculated that other factors including population demographics, crossreactive immunity, and climate could have contributed to the less severe outcomes, but this has been relegated to a short paragraph. in its current state, the article puts a lot of weight on public health interventions but could be strengthened with a bit more discussion on the other factors. the article would also benefit from a discussion on whether the planned public health interventions in the different countries were successfully implemented. experiences from other countries show that what was planned on paper is not what happened or is happening on the ground. a discussion on this within the article will aid the reader in the interpretation of the findings and recommendations. all in all, i commend the authors for a well-thought-out open letter and for their confidence as young scientists in driving opinion in africa. is the rationale for the open letter provided in sufficient detail? yes work. the following summary discussing the challenges faced in the implementation of the interventions described was added to the text. "it should be noted that implementation of the public health interventions for preparedness and response to the covid- pandemic in sub-saharan africa faced many challenges. overall, the assessed countries lacked the local biotechnological capacity for the production of biomedical supplies, they had a limited workforce with the expertise to specifically address the pandemic using evidence, there was lack of community trust , poor infrastructure , inability to manage remote education programs, failure to maintain the measures implemented due to the population economic instability , and insufficient funds. formal studies of the extent of these challenges and how to address them in future will be required." of international concern on january th , and a global pandemic on march th , by the world health organization (who). " we agree with the reviewer's comment on the need to draw the reader's attention to the changing dynamics of the covid- pandemic in ssa, to address this concern we updated the introduction to include that recent reports from south africa indicate a surge in weekly deaths from natural causes that may be attributable to covid- . we also clarified in conclusion that "this assessment was conducted during the first three month of the covid- pandemic before the virus spread widely in ssa and our conclusions were drawn based on statistical information on the disease presented in this study" ○ the sociocultural challenges mentioned in table refer to the misinformation about the consequences of the safety recommendations. as an example, misinformation has led to some interventions being termed harmful or unethical among some communities. examples include interventions such as wearing a mask which some have suggested is detrimental to health due to carbon dioxide poisoning, numerous faith-related rumors, whereby some religious leaders have spread misleading information that they are able to cure covid- . table was updated to clarify these points. outbreak of pneumonia of unknown etiology in wuhan, china: the mystery and the miracle pubmed abstract | publisher full text | free full text a novel coronavirus outbreak of global health concern pubmed abstract | publisher full text | free full text . egypt today: egypt announces first coronavirus infection who declares covid- a pandemic pubmed abstract | publisher full text . world health organization (who): who coronavirus (covid- ) dashboard the state and the informal in sub-saharan african urban economies: revisiting debates on dualism. cris states res cent work pap the urban informal sector in sub-saharan africa: from bad to good (and back again?) preparedness and vulnerability of african countries against importations of covid- : a modelling study pubmed abstract | publisher full text | free full text identifying key challenges facing healthcare systems in africa and potential solutions pubmed abstract | publisher full text | free full text intensive care unit capacity in lowincome countries: a systematic review pubmed abstract | publisher full text | free full text identifying future disease hot spots: infectious disease vulnerability index santhe: sub-saharan african network for tb/hiv research excellence. . reference source . the journal.ie: who warns africa is ill-equipped to deal with coronavirus due to "weaker health systems. ; published february . reference source . tasamba j: rwanda uses ebola experience to combat covid- south africa hopes its battle with hiv and tb helped prepare it for covid- . science ( -). . reference source . africa renewal: who:how the lessons from ebola are helping africa's covid- response reference source bbc news: coronavirus: most africans "will go hungry in -day lockdown high sars-cov- seroprevalence in health care workers but relatively low numbers of deaths in urban malawi. covid- sars-cov- prepr from medrxiv biorxiv why is there low morbidity and mortality of covid- in africa? access to lifesaving medical resources for african countries : covid- testing and response , ethics , and politics deadly masks" claims debunked intensive care unit capacity in low-income countries: a systematic review the state and the informal in sub-saharan african urban economies: revisiting debates on dualism. cris states res cent work pap identifying key challenges facing healthcare systems in africa and potential solutions reference source is the rationale for the open letter provided in sufficient detail? references . world health organization (who). world health organization: who director-general's statement on ihr deadly masks" claims debunked pastor who claimed he cured coronavirus with faith dies from illness we gratefully acknowledge the contributions of health care workers for their helpful discussions. we thank professor thumbi ndung'u for his guidance, dr victoria kasprowicz and dr denis chopera for their invaluable contribution to this work. we thank the reviewer for the constructive comments and important suggestions for improving this article. our responses are presented below:we agree with the reviewer that there are aspects of the covid- presentation in sub-saharan african that remain unresolved and require additional research. however, our goal here was to review that response in selected african countries and this preliminary analysis suggests a robust and effective response, notwithstanding other factors that may have influenced transmission dynamics and mortality. in response to the reviewer, we have under the conclusion the following clause that highlighted the importance of other factors driving the observations on infection dynamics of the covid- . "it was noted that zambia, which did not fully implement the interventions described in this study as well as other countries not included in our review that have struggled to put into action public health interventions, , reported no significant increases in deaths compared to countries with more robust responses reported here. there, consistent with the recent study by m. njenga et al which investigated the causes of low morbidity and low mortality of covid- in african countries, we also suggest that other factors such as a warm climate, young population, pre-existing cross-reactive immunity may have considerably contributed to the evolution of the covid- pandemic in ssa countries."we agree with the reviewer that further studies of the efficiency of implementation of public health interventions is required. this was beyond the scope of the current the authors write that this article is "based on an extensive review of the available scientific publications, the government technical reports and the announcements released by governmental and nongovernmental health organizations …". however, the authors do not provide a description of the search and selection of the literature used in this article. i suggest that they should provide this information in the article or as a supplementary document.the world health organization declared covid- a public health emergency of international concern on january and not in march . please refer to reference .the authors state that "notably, there is no significant increase in unexplained pneumonias or deaths recorded on the continent which could possibly indicate the effectiveness of interventions introduced by several african governments". while i generally agree with this statement, especially given the time they submitted the article, i would like to alert the authors to reports by the south african medical research council of a recent upsurge in weekly deaths from natural causes in south africa. please refer to reference .in table , what does the sociocultural challenge "suspicion of harmful and unethical interventions" mean? what are the harmful and unethical interventions and why and who offered the harmful and unethical interventions to whom?what are "faith-related rumors"? are all factual statements correct, and are statements and arguments made adequately supported by citations? partly where applicable, are recommendations and next steps explained clearly for others to follow? yescompeting interests: no competing interests were disclosed.reviewer expertise: systematic reviews and meta-analysis, implementation science, evidenceinformed policymaking, vaccinology.i confirm that i have read this submission and believe that i have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however i have significant reservations, as outlined above.author response sep gisele umviligihozo, simon fraser university, burnaby, canadawe thank the reviewer for the positive comments and suggestions for improving this article, our responses are as follows:to elaborate on the search criteria and to describe the research methodology used in the selection of the literature for this article, the following statement under "assessment and findings" was updated to reflect these steps. "we therefore decided to review articles focusing on sars-cov- infection dynamics in africa and the responses that african governments were taking. specifically, we used the free search engine pubmed to identify articles that discussed the transmission dynamics of the new sars-cov- virus, or described the sociocultural, economic and the state of health care systems in africa and their impact on sars-cov- transmission. moreover, we searched for popular media reports and performed internet searches at official websites for any documents or articles highlighting interventions against covid- implemented by african governments, local health authorities or nongovernmental health organizations. we also relied on our own personal experiences and perspectives." ○ we agree with the reviewer's comment on this date, a correction has been made to this statement which now reads "covid- was declared a public health emergency ○ competing interests: no competing interests were disclosed. key: cord- -yvid qps authors: bisimwa, patrick n.; ongus, juliette r.; tiambo, christian k.; machuka, eunice m.; bisimwa, espoir b.; steinaa, lucilla; pelle, roger title: first detection of african swine fever (asf) virus genotype x and serogroup in symptomatic pigs in the democratic republic of congo date: - - journal: virol j doi: . /s - - - sha: doc_id: cord_uid: yvid qps background: african swine fever (asf) is a highly contagious and severe hemorrhagic viral disease of domestic pigs. the analysis of variable regions of african swine fever virus (asfv) genome led to more genotypic and serotypic information about circulating strains. the present study aimed at investigating the genetic diversity of asfv strains in symptomatic pigs in south kivu province of the democratic republic of congo (drc). materials and methods: blood samples collected from asf symptomatic domestic pigs in of districts in south kivu were screened for the presence of asfv, using a vp gene-specific polymerase chain reaction (pcr) with the universal primer set ppa -ppa . to genotype the strains, we sequenced and compared the nucleotide sequences of ppa-positive samples at three loci: the c-terminus of b l gene encoding the p protein, the e l gene encoding the p protein, and the central hypervariable region (cvr) of the b l gene encoding the j l protein. in addition, to serotype and discriminate between closely related strains, the ep l (cd v) gene and the intergenic region between the i r and i l genes were analyzed. results: asfv was confirmed in of pigs tested. however, only and ppa-positive samples, respectively, were successfully sequenced and phylogenetically analyzed for p (b l) and p (e l). all the asfv studied were of genotype x. the cvr tetrameric repeat clustered the asfv strains in two subgroups: the uvira subgroup ( trs repeats, aaaabnaaba) and another subgroup from all other strains ( trs repeats, aabnaaba). the phylogenetic analysis of the ep l gene clustered all the strains into cd v serogroup . analyzing the intergenic region between i r and i l genes revealed that the strains were identical but contained a deletion of a -nucleotide internal repeat sequence compared to asfv strain kenya . conclusion: asfv genotype x and serogroup was identified in the asf disease outbreaks in south kivu province of drc in – . this represents the first report of asfv genotype x in drc. cvr tetrameric repeat sequences clustered the asfv strains studied in two subgroups. our finding emphasizes the need for improved coordination of the control of asf. pigs are increasingly contributing to improved nutrition and household incomes in regions of africa where pork consumption and pig keeping are culturally acceptable [ ] . despite the importance of pig farming, this sector is facing several constraints, with infectious disease burden being the major problem [ ] . african swine fever virus (asfv) causes an acute, highly contagious, and fatal disease in domestic pigs, with clinical signs such as fever and haemorrhagic lesions [ ] . there are currently no vaccines available to combat african swine fever (asf). the first recorded asf outbreaks were reported in pigs belonging to european settlers in kenya in [ ] . the disease continues to spread throughout eastern europe since [ ] and was reported in belgium and china in [ ] [ ] [ ] . asfv is a large, enveloped, doublestranded dna arbovirus belonging to the genus asfivirus, and the only member of the family asfarviridae [ , , ] . warthogs, bush pigs and the soft tick of the genus ornithodoros are the major reservoirs of asfv [ ] . the contagious nature and the ability to spread rapidly in pig populations over long distances makes it the most feared disease of domestic pigs [ , ] . the genome size varies from to kbp and encodes between and open reading frames, depending on the virus strains [ ] . to date, asfv genotypes have been reported worldwide based on the b l gene, which encodes the capsid protein p , and all of them are known to circulate in africa [ ] [ ] [ ] . using the serotype-identification approach [ ] , an additional asfv serotypes have been reported based on the ep r gene encoding the cd v protein [ ] [ ] [ ] . distinct antigenic types of asfv were identified based on haemadsorption inhibition (hai) serological typing, where asf protective immunity was shown to be serotype-specific, and viruses belonging to identical serogroups cross-protected against each other [ ] . this has significant importance for vaccine development. the cd v protein, encoded by the asfv ep r gene, is a transmembrane glycoprotein located in the viroplasm (around viral factories) and in the plasma membrane of infected cells. it is among the most variable genes in the asfv genome [ , ] . haemadsorption involves adhesion of pig erythrocytes to the surface of asfv infected cells, a key requirement is expression of cd v in asfv-infected cells [ ] . control of the disease is relying on surveillance, restriction of pigs and pork products movement, and rapid diagnosis and culling of asfv infected animals. the implementation of these measures is particularly difficult for african pig farmers of which many can be characterized as smallholders, due to limited capacity and appropriate policy. in , asf outbreaks were reported in more than african countries with the highest number of outbreaks ( ) registered in the democratic republic of congo (drc) causing a loss of , pigs [ , ] . previous studies have reported circulation of genotype i, ix and xiv in drc, encouraging the need for continued characterization of asfv strains responsible for outbreaks to better understand the spread of this economical important disease in drc. several variable regions of the asfv genome have been extensively used as targets for molecular epidemiology studies of asfv strains [ ] [ ] [ ] . however, previous studies achieved high resolution for discrimination between different virus strains when combining p , p and b l (central variable region or cvr) proteins [ , ] . moreover, the ep r gene encoding the cd v protein and the intergenic region between the i r and i l have also been used to characterize asfv from various locations and to track virus spread [ , ] . the first report of the presence of asf in drc was in [ ] . south kivu province is an area in the eastern drc where suspected cases of asf appear regular. reports from the provincial ministry of agriculture livestock and fishery (pmalf) and the local veterinary body indicated the death of pigs out of that presented clinical signs of asf in (report of the pmalf, unpublished data). more recently, we have used a combination of p and p proteins to characterize asfv genotype ix in apparently healthy pigs in south kivu province sampled in [ ] . it was the first study of asfv in the south kivu province. however, despite report of frequent incidences of asf in the south kivu province by the pmalf, information about asfv strains in circulation in suspected infected animals is lacking. therefore, the present study was set up to identify and characterize asfv strains in infected domestic pigs with symptoms of asf from different smallholder farms in the south kivu province in order to increase epidemiological knowledge of asfv, and to generate information for improvement of control strategies. ethical approval for the study reported here and the permission for the collection of samples was provided by the interdisciplinary centre for ethical research (cire) established by the evangelical university in africa, bukavu, dr congo, with reference (uea/sgac/km / ). a consent form which described the aim of the study was signed by farmers willing to participate in the study after translation into local languages. the study was carried out in south kivu province of the democratic republic of congo (drc), situated in the eastern part of the country. it is a large region with an area of , km , located between longitudes ° ′ ″ and ° ′ east, latitudes ′ ″ and ° ′ ″ south. comparatively, the south kivu province is over two times the size of burundi ( , km ) and rwanda ( , km ) put together. the province experiences two main seasons: a -month long rainy period, from september to may, and a -month dry period (june to august). the annual average rainfall is mm. six out of eight territories were selected for purposes of this study including; fizi, kabare, kalehe, mwenga, uvira and walungu (fig. ) . a key factor in selecting the sample sites was the inclusion of the main pig-producing, marketing, and consuming areas, with a particular focus on locations where suspected asf outbreaks had been recently reported by the provincial ministry of agriculture livestock and fishery. a cross-sectional study was conducted where the target population was households that keep pigs, and where suspected asf cases were notified based on the reports from the local veterinary and provincial ministry of agriculture livestock and fishery during december to january . in general, the number of pigs per farm varied between and and they shared housing. thus, farms with pigs presenting symptoms such as high fever, reddening of the skin, particularly ears and snout, coughing and difficulties in breathing, hemorrhagic diarrhea and vomiting, inability to walk, loss of appetites, general weakness, were considered for sampling and all the pigs were sampled. drc has a pig population of approximately million. the recommended sample size for a population of that size, using a confidence level of % and a margin of error of % would be [ ] . based on this, a total of blood samples from suspected asfv infected pigs were collected in edta (anticoagulant) tubes and were used for pcr analysis. all blood samples were collected from the jugular vein of pigs of over months of age. after collection, all collected blood samples were transported to the université evangélique en afrique (uea) and stored at − °c before being shipped on ice packs to the pan african university institute of science technology and innovation (pauisti) in nairobi then to beca-ilri hub, for subsequent analysis. total dna was extracted directly from μl of whole blood using the dneasy blood and tissue kit (qiagen, usa) following the manufacturer's recommendations. to detect the presence of asfv dna, polymerase chain reaction (pcr) amplification assay was carried out using the asfv diagnosis primers ppa /ppa (peste porcine africaine) that target the virus vp (p ) coding region to generate an amplicon of bp [ ] . pcr products were confirmed using a % agarose gel electrophoresis. all ppa-positive samples were characterized in subsequent analyses. five separate pcr experiments were set up to amplify ppa-positive samples: (i) for p genotype classification, the c-terminal region of the p protein gene was amplified using the primers p -u/d [ ] ; (ii) for p genotyping, the gene e l encoding the p protein was amplified using the primers ppa /ppa [ ] ; (iii) the b l gene characterized by the central variable region (cvr) was amplified using the primer pairs cvr-fl and cvr-fl as previously reported [ ] ; (iv) for determining the origin, and to distinguish between closely related asfv strains circulating in the south kivu province, a bp fragment, specific for identification of tandem repeat sequences (trs), located between the i r and i l genes was amplified using the primer pairs eco a and eco b [ ] ; (v) to determine the serogroups of the strains, the partial ep r gene encoding the cd v protein [ ] was amplified and sequenced using two sets of primers to generate two overlapping fragments. the primers used for the diagnosis and genotyping are presented in the table . pcr amplicons were confirmed using % agarose gel electrophoresis in the presence of molecular weight markers. for sequencing, pcr products were purified using quick pcr purification kit (qiagen, usa) following the manufacturer's instructions and sent to macrogen europe bv (amsterdam, the netherlands) for sanger sequencing. open reading frames present within the sequences generated from the amplified cvr dna fragments were translated into amino acid sequences using emboss-transeq software [ ] . both strands of purified amplicons were sequenced using the primer sets for genotyping described above. to verify similarity with known sequences, the amplicon sequences obtained were submitted to blast (basic local alignment search tool) [ ] against non-redundant genbank database. multiple sequence alignments of sequences were generated using clustal w [ ] , whereas for each locus, the unrooted maximum likelihood method (ml) phylogenetic tree with bootstrap replications was estimated by mega program and kimura -parameter model [ ] was selected based on the best-fit substitution model (ml) with the lowest bayesian information criterion (bic) score. asfv sequence data of strains and isolates available in the genbank were included as references. sequences from this study have been submitted to genbank with accession numbers mn to mn (for p ) and mn to mn (for p ). a total of blood samples collected from symptomatic pigs were screened for the presence of the asf viral dna using conventional pcr with the diagnostic primers ppa /ppa . a total of blood samples showed clear amplicons of the expected size ( bp) and data were distributed as shown in table , with the highest number of positive samples found in the uvira territory / ( . %), while the lowest was in mwenga / ( . %). sequence analysis of asfv based on the b l (p ), e l (p ) and b l (cvr) genes of the asfv positive samples using ppa diagnostic primers, we successfully amplified and sequenced ( . %) samples for p and ( . %) samples for p ( table ). the p amplicon sequences shared - % identity due to some few synonymous mutations while the p sequences were % identical (data not shown). thus, clustal protein sequence alignment showed % identity between all the p and p sequences in the study samples. sequences of p and p amplicon were compared with other p and p asfv sequences retrieved from the gen-bank database and the phylogenetic analysis revealed that the south kivu asf virus strains analyzed clustered with p genotype x including strains reported in previous studies in burundi (af ), kenya (ay ) and tanzania (jx , af , mf ) ( fig. a and b) . this is the first report of genotype x in the drc. in addition, the predicted amino acid sequences of the cvr nucleotide sequences were generated from samples ( fizi, kabare, kalehe, mwenga, uvira, walungu) and specific features based on the previously reported asfv tetrameric amino acid repeats within the cvr [ , ] were obtained. analysis of the cvr signature of the b l gene showed two different signatures when compared with sequences of strains of the same genotype from burundi, tanzania and uganda. all asfv strains contained a cvr with tetrameric amino acids, namely cast (a), cadt (b) and nvdt (n). however, in strains from the uvira territory the cvr sequence was repeated times with the profile aaaabnaaba. in contrast, in strains from the five other territories, the cvr sequences contained only repeats with the signature aabnaaba (table ). both cvr signatures were different from the strains tan /moshi, bur / , bur / and ug / [ ] [ ] [ ] . no. strains positive for asfv using the pcr assays a pcr assays were performed on the samples positive for ppa pcr sequence analysis of the intergenic region between i r and i l genes and the ep r gene amplification of the ep r gene (encoding cd v protein) was performed, and pcr amplicons of strains from territories were successfully sequenced. comparative analysis of the sequences obtained was carried out together with other asfv sequences retrieved from the genbank database and previously characterized as serogroups. in this study, the phylogenetic analysis showed that the south kivu strains belonged to serogroup and were grouped with the uganda strain (km ), the only available serogroup in the gen-bank. this research suggests that the strains from this study may have a similar hemadsorption inhibition (hai) characteristics as the only known strain serogroup (fig. ) . the analysis of whole-genome sequences of asfv has facilitated identification of several regions containing tandem repeat sequences, important for discriminating between closely related asfv strains and for predicting the origin of the virus [ ] . in this study, the intergenic region between the i r and i l genes was analyzed for strains from the territories studied. the south kivu asfv strains were compared to the kenyan strain (ay ), which was identified from a domestic pig. the sequence alignment showed an indel of bp ( ′-cctatatacctataatcttataccctataa tct- ′) between nucleotide position to (fig. ). african swine fever constitutes the major obstacle to the development of the pig industry in the drc, with sporadic outbreaks occurring across various areas throughout the year [ ] . despite recurrent occurrence of suspected asf outbreaks in south kivu province, information on the virus characterization remains scarce. to determine the prevalence of asf and genotypes of asfv in circulation in the south kivu province, a study was carried out in the south kivu province from january to august , a period with no report of asf outbreaks a b fig. phylogenetic relationships of p and p genotypes. the evolutionary history was inferred by the maximum likelihood method based on the kimura -parameter model [ ] . phylogeny was inferred following bootstrap replications, and the node values show percentage bootstrap support. scale bar indicates nucleotide substitutions per site. scale bar indicates nucleotide substitutions per site. a p genotypes. the analysis included b l (p ) sequences from this study (plain circle ) and sequences from the genbank database. the genbank accession numbers for the different b l (p ) genes are indicated in parenthesis. b p genotypes. the analysis involved e l (p ) gene sequences of african swine fever viruses from this study (black diamond ◆) and sequences from the genbank database. the sequences for the different b l (p ) and e l (p ) genes are starting by genbank accession numbers or cases in the sampled area [ ] . we conducted a cross-sectional study in of the districts of the province and pig blood from smallholder pig farms were screened for presence of the asfv antibody and viral genome using indirect enzyme linked immunosorbent assay (elisa) and polymerase chain reaction (pcr), respectively, on asymptomatic domestic pigs. we found that % of pigs contained asfv antibodies whereas virus dna was present in . % of pigs. sequence analysis revealed that all the asfv detected from asymptomatic pigs belonged to the genotype ix. continuous characterization of asfv strains is key in endemic regions to better understand disease outbreak patterns and map the different strains according to their geographical regions, in which they circulate [ ] . the present study was targeting domestic pigs showing asf clinical signs with the aim to characterize asfv in symptomatic animals in the south kivu province. we confirmed the presence of asfv in domestic pigs with clinical signs of asf in the six studied territories of south kivu province: kabare, kalehe, fizi, mwenga, uvira and walungu. although this study was not designed to determine the prevalence of asfv, low rate of infection was observed in mwenga and kalehe ( and . %, respectively), whereas the highest infection rates were registered in walunga and uvira ( and . %, respectively). in our previous study which included asymptomatic pigs [ ] , walungu had the highest prevalence of asfv ( . %) while the lowest asfv prevalence was found in kalehe ( . %). the overall low infection rate may be attributed to the sensitivity of the assay used. indeed, the conventional pcr method used in this study is less sensitive than other molecular methods such as nested-pcr [ ] and real-time pcr [ ] and may fail to detect potentially positive samples containing very low amount of viral genetic material. in addition to the low sensitivity of the conventional pcr used, other conditions may have contributed to the observed low prevalence including: (i) most pigs sampled may not have been infected or may have low virus load not detectable by the pcr technique used; and (ii) suspected pigs may have been affected by other diseases and conditions with similar symptoms to asf such as porcine reproductive an respiratory syndrome, porcine dermatitis and nephropathy syndrome, salmonellosis. our results confirmed asf viral infections in pigs with clinical signs of asf in the south kivu province. from the ppa-pcr positive samples, , and samples were successfully amplified and sequenced for b l (p ), e l (p ) and b l (cvr) genes, respectively. the combination of these three viral regions is to ensure a high-level resolution for asfv discrimination. the p genotyping study corroborated the p analysis. both p and p phylogenetic analyses clustered asfv strains in circulation in symptomatic domestic pigs during the december -january outbreaks in the south kivu province with asfv genotype x, which is the major genotype associated with asf outbreaks throughout burundi, in some parts of tanzania, kenya and uganda [ , ] . genotype x has been reported to be a sylvatic cycle-associated genotype that include asfv identified from domestic pigs, warthogs as well as ticks in these three countries [ , , ] . furthermore, alignment of the bp long sequence from the variable ′-end of the b l (p ) gene in the south kivu viruses showed % identity with asfv strains from burundi (data not shown). it is a possibility that viruses in this study may originate from, or could have expanded to burundi. this scenario seems plausible as the south kivu province is bordering burundi through the river rizizi and lake tanganyika, and uncontrolled cross-border movements of pigs and pork products are observed in the region and may constitute a major route of transmission of asf in this endemic area [ ] . our current result contrasts with our previous finding of circulating asfv strains of genotype ix in asymptomatic domestic pigs in the studied area during a period with no asf outbreaks or cases [ ] . it is unlikely that data from both studies suggest that asfv of genotype ix may not cause disease in pigs whereas [ ] . although the report did not have any cases in the south kivu province, it identified asfv of genotype i in the neighboring province of maniema. nevertheless, further investigation in relation to both the host and virus genetics will be important to understand our findings. we are currently working on the lab-isolation of viruses of genotype ix and x in circulation in asymptomatic pigs and symptomatic pigs, respectively, for complete genome sequencing and comparative genomic analysis. data obtained will improve our understanding of this contrasting finding in pigs within the south kivu province. to the best of our knowledge, this is the first report of asf virus genotype x in the dr congo. as all the strains were p /p genotype x, we further characterized them at a higher resolution using the intra-genotypic central variable region (cvr) of the bl l gene. based on the tetrameric repeat sequences (trs), our analysis identified two different cvr variants, clustering the strains into two subgroups. subgroup was composed only of strains from uvira characterized by trs whereas all other strains formed the subgroup and had only trs. the profile of the subgroup (aabnaaba) was almost identical to the cvr amino acid sequence of uganda / (aabnbaba), having the b code (cadt) in place of a at the th repeat [ ] . the number of trs repeat observed is relatively small compared to reports from some studies in the same geographic region describing the trs motif repeated over to times [ , ] . however, mulumba-mfumu et al. also observed this sequence repeated only or times in some dr congo strains [ ] . the two cvr variants found in our study were different from the previously reported variants in dr congo asfv strains [ ] and to any other known viruses causing outbreaks or asf cases, thus suggesting that the asfv genotype in circulation in the south kivu province of dr congo identified in this study may be unique [ , ] . within the vaccine field, it has been suggested that protective immunity is serotype-specific, as defined by asfv hemadsorption inhibition (hai) serological assay, with viruses within a serogroup cross-protecting against one another [ , ] . the hai assay can be used to type asfv of a given genotype into distinct and individual serogroups, based on the asfv proteins cd v (ep r) and/or c-type lectin (ep r). thus, hai-based serogroup classification has been suggested as a better correlate for in vivo cross-protection among strains compared to the p genotyping [ ] . in our study, we obtained cd v sequences of strains from territories and comparative sequence analysis revealed that they were all identical. moreover, phylogenetic analysis showed that the uganda strain (genbank acc. no. km . ), which represents the only member of the serogroup , was closest related to the south kivu viruses, suggesting that the asfv strains, identified in this study, may belong to serogroup . the high bootstrap value of % grouping the south kivu strains with the uganda serogroup and the fact that strains from this study showed . % amino acid identity with the uganda serotype strain strongly support the genetic relatedness between these two groups. it is worth noting that strains of serogroups and have been reported in drc [ ] . overall, our data showed that these south kivu asfv strains are serologically different from other strains reported so far. analysis of the intergenic region between the i r and i l genes has previously been used for distinguishing between closely related asfvs [ ] . characterization of fig. partial nucleotide sequence alignments of the intergenic region between i r and i l genes. sequences of african swine fever virus (asfv) strains from the south kivu province, eastern drc, showing tetrameric repeats of representative genotypes, including a reference sequence of a virus isolated in in kenya (kenya ; genbank accession no. ay . ). the indel that results from the insertion of the nucleotide sequence cctatatacctataatcttataccctataatct in the asfv from kenya is boxed this intergenic region genes did not identify any genetic diversity among the south kivu strains. however, all the strains analyzed had high sequence identity with the kenyan strain (genbank acc. no. ay ) but lacked an insertion of bp. indels have also been reported in a similar analysis [ ] . altogether, our study provided evidence of circulating asfv genotype x which were antigenically related to serogroup in domestic pigs with clinical signs of asf in eastern drc. the genotyping approach was also supported with the hai serotyping for improved diversity analysis and finer discrimination of asfv strains. this represents the first report of asfv genotype x in drc. in this study, asfv isolated from symptomatic domestic pigs in the south kivu province of the democratic republic of congo were characterized for the genetic diversity. all the asfv strains analyzed in this study belonged to the p genotype x and the cd v serotype . this is the first report of circulating asfv genotype x in drc. the genetic similarity of these strains suggests that they may originate from a common source. however, cvr tetrameric sequence repeat analysis clustered the strains into a subgroup with tsr (uvira strains) and a subgroup with trs (strains from other territories), thus underlining genetic variation among these asfv. therefore, a better understanding of asfv evolution and spread throughout the south kivu province will need further in-depth comparative sequence analyses including whole genome sequencing of asfv strains 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genetic characterization of african swine fever viruses from a outbreak in tanzania. transb and emerg dis molecular epidemiology of african swine fever virus studied by analysis of four variable genome regions genetic assessment of african swine fever isolates involved in outbreaks in the democratic republic of congo between and reveals co-circulation of p genotypes i, ix and xiv, including variants molecular characterization of african swine fever viruses from outbreaks in peri-urban kampala, uganda development of a nested pcr and its internal control for the detection of african swine fever virus (asfv) in ornithodoros erraticus molecular diagnosis of african swine fever by a new real-time pcr using universal probe library african swine fever viruses with two different genotypes, both of which occur in domestic pigs, are associated with ticks and adult warthogs, respectively, at a single geographical site transmission routes of african swine fever virus to domestic pigs: current knowledge and future research directions prevalence of african swine fever virus in apparently healthy domestic pigs in uganda molecular characterization of african swine fever virus in apparently healthy domestic pigs in uganda publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations we acknowledge the biosciences eastern and central africa authors' contributions bnp collected samples for dna isolation, performed laboratory work and wrote the manuscript; jro supervised the study, conceived and designed the study, and edited the manuscript; ckt performed the laboratory work and edited the manuscript; emm performed the laboratory work and sequence analysis; ebb conceived and designed the study and edited the manuscript; ls supervised the study and edited the manuscript; rp supervised the study, performed sequence analysis, wrote and edited the manuscript. all authors read and approved the manuscript. this work was funded by the biosciences eastern and central africa -international livestock research institute (beca-ilri) hub, through africa biosciences challenge fund (abcf). the datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.ethics approval and consent to participate see material and methods section. not applicable. the authors declare that they have no competing interests.author details department of molecular biology and biotechnology, pan african university, institute of basic sciences, technology and innovation, nairobi, kenya. key: cord- - t y gqq authors: roy, siddhartha; dickey, sabrina; wang, hsiao-lan; washington, alexandria; polo, randy; gwede, clement k.; luque, john s. title: systematic review of interventions to increase stool blood colorectal cancer screening in african americans date: - - journal: j community health doi: . /s - - -z sha: doc_id: cord_uid: t y gqq african americans experience colorectal cancer (crc) related disparities compared to other racial groups in the united states. african americans are frequently diagnosed with crc at a later stage, screening is underutilized, and mortality rates are highest in this group. this systematic review focused on intervention studies using stool blood crc screening among african americans in primary care and community settings. given wide accessibility, low cost, and ease of dissemination of stool-based crc screening tests, this review aims to determine effective interventions to improve participation rates. this systematic review included intervention studies published between january , and march , . after reviewing an initial search of studies, studies were eventually included in this review. the included studies were studies conducted in community and clinical settings, using both inreach and outreach strategies to increase crc screening. for each study, an unadjusted odds ratio (or) for the crc screening intervention compared to the control arm was calculated based on the data in each study to report effectiveness. the eleven studies together recruited a total of participants. the five studies using two-arm experimental designs ranged in effectiveness with ors ranging from . to . using interventions such as mailed reminders, patient navigation, and tailored educational materials. effective strategies to increase stool blood testing included mailed stool blood tests augmented by patient navigation, tailored educational materials, and follow-up calls or mailings to increase trust in the patient-provider relationship. more studies are needed on stool blood testing interventions to determine effectiveness in this population. although all population groups in the u.s. are affected by cancer, minority communities experience a higher cancer burden. notably, african americans exhibit higher cancer death rates and lower survival rates compared to other racial or ethnic groups [ ] . minority communities are more likely to be poor, medically underserved, and have limited access to quality health care, leading to cancer health disparities. these persistent disparities may be attributed in part to lower rates of completing recommended cancer screenings and increased risk factors, which are more prevalent among low-income and uninsured individuals living in minority communities [ ] . colorectal cancer (crc) is the third most commonly diagnosed cancer in men and women in the united states with an estimated , new cases [ ] . crc continues to affect african americans at disproportionately higher rates than non-hispanic whites despite improved screening and treatment (jackson, oman, patel & vega, ). the crc incidence rate between and was % higher for african american men and % higher for african american women [ ] . moreover, crc mortality rates were % higher in african american men and % higher in african american women than in non-hispanic whites [ ] . the cancer health disparity in mortality is decreasing at a faster rate in african american women than in men, possibly due to differences in risk factors (e.g., physical activity and diet) and from higher crc screening rates in women which has improved early detection [ ] . other factors associated with crc disparities across the cancer continuum may include genetic and microbiomic influences, differences in tumor biology, environmental causes, structural barriers such as costs, transportation and availability of healthcare facilities, and individual barriers including lack of knowledge, low self-efficacy, low health literacy, and mistrust of providers [ , ] . patient factors, provider-related factors, health care system-related factors, and structural factors all contribute to crc disparities for african americans [ ] . in the current era of covid- , elective surgeries are being postponed and cancer screenings deferred because of fear of exposure to the virus in hospitals and clinics; therefore, mail-based screenings such as stool blood crc screening are a safer alternative. the u.s. preventive service task force recommends that screening for crc start at age and continue until age [ ] . crc screening options generally include a high-sensitivity stool blood test [fecal immunochemical test (fit), guaiac-based fecal occult blood test (gfobt), or multitarget stool fit-dna test)] or a direct visualization test (colonoscopy, flexible sigmoidoscopy, or ct colonography). early detection with colonoscopy can detect precancerous polyps and abnormalities in the colon and rectum to reduce mortality with this test which is done every years. crc screening may also involve annual stool blood tests, such as the fit or gfobt, and follow-up with diagnostic colonoscopy if needed for abnormal findings. communication of abnormal fit results are associated with improved adherence to follow-up colonoscopy [ ] . the american cancer society (acs) recently updated its screening recommendations with a "qualified recommendation" for beginning crc screening for adults beginning at years old and a "strong recommendation" for beginning screening at years and older until the age of in may . a recent study reported that crc screening more than doubled among people between and years since the acs guideline change [ ] . in , the american college of gastroenterology (acg) recommended that african americans begin screening at years old [ , ] . the difference in age recommendations is related to the type and quality of evidence for individuals aged - years old. currently, the most common tests used in the u.s. to adhere to crc screening recommendations include either a colonoscopy every years or an annual stool blood test (fit or gfobt). there is no consensus on which test recommendation will yield higher adherence rates to crc screening recommendations; however, studies suggest that stool blood tests may be more acceptable and beneficial for african american communities to reach recommended screening levels [ ] . moreover, there are many regions of the u.s. where access to colonoscopy is suboptimal [ ] . a previous systematic review focused on crc screening by colonoscopy in african americans concluded that patient, provider, and systematic barriers to screening could be modifiable to improve screening rates [ ] . these barriers were classified into the following three domains: ( ) patient factors-psychological (fear) and lack of knowledge; ( ) provider factors-confusion about age recommendations, low knowledge of patient barriers, and lack of counseling; and ( ) system factorscosts, insurance coverage, and limited primary care visits [ ] . other barriers to crc screening adherence include difficulty in scheduling appointments, provider preferences for one screening modality over another which may limit access, poor healthcare infrastructure including low access to gastroenterology specialists, and available health education resources. while many crc screening interventions focus on increasing colonoscopy screening, stool blood tests can be done in the privacy of a person's home, are more cost effective, and can yield higher rates of adherence [ , ] . while there are many different intervention possibilities to ameliorate these cancer health disparities, focusing on increasing colorectal cancer screening in minority and underserved communities is one that has been widely implemented in both health care system and communitybased contexts using both outreach and inreach strategies [ ] [ ] [ ] [ ] [ ] [ ] [ ] . many of these programs emphasize colonoscopy screening, which is an example of an invasive screening, but several other methods of noninvasive screening tests exist, but require more frequent screening intervals. mailed invitations to complete stool blood testing is an effective outreach approach frequently used by medical providers. to critically assess and synthesize the available evidence for the effectiveness of colorectal cancer screening programs in primary and community health care, this systematic review aims to review quality studies testing different strategies for increasing stool blood colorectal cancer screening rates in african americans. there have been no systematic reviews focused specifically on clinical and behavioral interventions to increase stool blood colorectal screening. studies might include both endoscopic and stool blood methods for their outcomes, but this review sought to identify studies focused on stool blood testing, as a less expensive alternative to colonoscopy in minority communities. the objective of this systematic review is to assess the effectiveness of colorectal cancer screening using stool blood testing approaches, specifically in studies which included either exclusively african americans, or were conducted in health systems with a high proportion of african american patients. the inclusion criteria were the following items: . studies using a randomized controlled trial or quasiexperimental study design. control groups could include both usual care or other types of clinical or behavioral interventions to increase colorectal cancer screening such as may be used in comparative effectiveness study designs. . studies had to include substantial participants of african americans (> % of the study sample) and be conducted in the u.s. . studies needed to include a screening completion outcome involving stool blood testing such as high sensitivity and high specificity gfobt, fobt, or fit. . only peer-reviewed studies published in scientific journals were included. the exclusion criteria were the following items: . studies that were literature reviews, case studies, or quality improvement initiatives without an experimental research design. . studies that did not include a comparison group. . studies that duplicated the findings from another previously published study to report findings on a subset of participants from the original study. . studies that did not measure a colorectal cancer screening outcome, such as studies which only measured changes in knowledge or screening intentions. . studies that did not include greater than % african americans in the participant sample. . studies conducted outside of the u.s. a research librarian searched bibliographic databases which included scopus, web of science, and cinahl from database inception until march , . the following syntax illustrates the search strategy used: ((colon or colorectal or sigmoid or rectum or rectal or colonic or anus) n (cancer or neoplasm or tumor or tumour)) and (((stool or feces or fecal or faeces or faecal) n ( screen* or specimen)) or immunochem* or immunoassay* or "occult blood" or fobt) and (black or blacks or "african american" or "african americans") after the search of bibliographic databases, citations were identified. eight references were eliminated since there were no author names and were either published guidelines or news articles that included no screening outcome or intervention. next, duplicates were identified, and the database was reduced to references. two independent reviewers examined the remaining articles using the inclusion and exclusion criteria and articles met criteria for full text review. articles published before were eliminated. the rationale for excluding older articles was to account for recent advances in stool blood crc testing technology, such as the introduction of stool dna (sdna) technology in and the later approval of fit by the centers for medicare and medicaid services (cms) in [ ] . a third reviewer examined all decisions of the two independent reviewers to resolve disagreements on article inclusion and conducted the full text review of the articles ( fig. ) . after a thorough review of each article, articles were additionally excluded, leaving a final group of articles for article abstraction [ , [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] . the most common reasons for excluding articles included: ( ) less than % of the study sample were african american; ( ) did not meet study design parameters; ( ) no study outcomes included stool blood test outcomes; and ( ) review articles or qualitative studies. to abstract information from each study, the reviewers employed a form adapted from a previous systematic review [ ] . the form included questions on sample setting, sample size, study design, randomization procedures, follow-up time periods, target population, intervention description, control group description, participant demographics, type of screening tests, means of screening confirmation (chart versus self-report), and study outcomes by study arm and screening adherence. two reviewers collected information from the included articles independently on the article abstraction form and discussed any discrepancies in data abstraction to come to consensus. there was substantial heterogeneity among the studies identified based on study design, sample size, follow-up time period to measure outcomes, and study site/setting. for example, several studies used more conventional experimental designs with two study arms, other studies were efficacy studies comparing two variations of an intervention, while other studies used three or more study arms or factorial designs. for study site, some studies were clinic-based while others were community-based, so the target population for these studies were considerably different. for each study, an unadjusted odds ratio (or) for the crc screening intervention compared to the control arm was calculated based on the raw data reported in each study to determine the effectiveness. given the substantial heterogeneity between included studies, the decision was made not to conduct a meta-analysis since it was not possible to calculate an overall summary or estimate for the odds of receiving a stool blood test at time of primary study completion. moreover, for a few studies, it was not possible to disaggregate specific types of crc screening test completion in the outcome data (e.g., colonoscopy versus gfobt), which is acknowledged in the study limitations. for the identified studies, eight of the studies included african american study participants of greater than % of the total sample ( table ) . three of the studies included study samples of african americans ranging between and % [ , , ] . the included studies had greater proportion of african american women participants compared to men (range - %). most of the studies included participants in the age range for recommended colorectal cancer screening (i.e., to years). however, of the studies, one study focused on only older participants between - years [ ] , and two studies enrolled older individuals up to age years [ ] or years [ ] . education level varied among participants in the included studies. four of the studies reported that > % of participants had completed high school [ , [ ] [ ] [ ] , whereas four other studies reported < % [ , - , - , ]. the other three included studies did not report on education level [ , , ] . included studies varied in study designs ( table ) . six of the studies were randomized controlled trials with two study arms. many of these studies were comparing an enhanced intervention in clinical settings, such as using patient navigation or telephone outreach compared to a standard intervention approach using mail-delivered stool blood tests. other two-arm studies were efficacy studies, for example comparing different combinations of educational materials for fit completion [ ] or comparing variations of a church-based community intervention [ ] . three of the other included studies employed three study arms or a factorial design. the interventions in these studies included community-based approaches (e.g., lay health advisors) [ ] and educational approaches in clinics (e.g., pamphlets and videos) [ , ] . two of the included studies conducted interventions in rural areas [ , ] . the results for the two-arm randomized controlled studies ranged in effectiveness (table ) . some studies reported modest improvements. for example, one study reported a % increase in crc screening from baseline using a telephone outreach strategy [ ] and another study reported a % increase in crc screening from baseline using a video intervention [ ] . however, a few studies reported more dramatic increases in crc screening participation, with one study reporting an % screening adherence postintervention from implementing a tailored print intervention and fit kit [ ] . the five studies using two-arm experimental designs ranged in effectiveness with odds ratios (or) ranging from . to . using interventions such as mailed reminders, patient navigation, and tailored educational materials [ , , , , ] . while the study by goldberg et al. [ ] had a large or ( . ; ci . - . ), there was a small sample size of only participants. two studies with large samples which focused on increasing stool blood testing were found to have findings that did not reach statistical significance, such as the study by friedman et al. [ ] with an or of . (ci . - . ) and the study by horne et al. [ ] with an or of . (ci . - . ). the myers et al. study [ ] tested a tailored navigation intervention compared to standard mailed reminders and found significant results with an or of . (ci . - . ) for the fit screening outcome only. the results for the three-arm studies also ranged in effectiveness (table ). similar to the two-arm studies, some studies reported modest differences between intervention and control. for example, one study reported a % increase in crc screening from baseline using a tailored print and video intervention [ ] ; a second study reported a % increase in crc screening from baseline using a decision aid intervention [ ] ; and a third study reported a % increase in crc screening from baseline using different variations of a mailed intervention [ ] . however, one study reported a more dramatic increase in crc screening of % screening adherence post-intervention following receipt of a tailored group intervention using video education in senior centers [ ] . while several of these studies used either -month or -month primary outcomes, a few studies examined repeat stool blood testing outcomes during a longer time period, such as the study by arnold et al. which examined third-year stool blood testing outcomes [ ] . for nine of the studies included in the review which used random assignment of participation to intervention or control arm, there was relatively low attrition of participants. for the clinical studies, outcomes could be tracked for virtually all participants through electronic patient records. a few studies reported higher research participant attrition between and %. the most common limitation reported was the higher number of african american female participants than male in several studies. in addition, a few studies cited crc screening outcomes based on self-report, which is less reliable than patient chart verification (table ). this systematic review examines summary findings from experimental studies designed to test the effectiveness of interventions to increase colorectal cancer screening, specifically using stool blood crc screening approaches such as fit or gfobt in african american communities. the eleven studies together enrolled a total of participants ( % african american). based on these summary findings which tested effectiveness of clinical and behavioral interventions, a tailored navigation approach either by telephone or in person, might be a potentially effective strategy for increasing crc screening in african american communities as these interventions tested in two arm studies to control conditions were associated table methodological quality of included studies allocation methods attrition other potential limitations arnold et al. [ ] quasi-experimental low attrition reported ( %) method of determining fobt receipt not reported. differences between arms in sociodemographics, and sample was predominately composed of african american female participants in fqhcs basch et al. [ ] random assignment low attrition ( % in intervention arm; % in control arm) all participants had health insurance and a physician, and stool blood test kits were not provided campbell et al. [ ] random assignment medium attrition reported ( %) method of determining crc screening was based on self-report. there was a small sample size and factorial design limited comparative analysis christy et al. [ ] random assignment not reported not possible to isolate providing the fit kit from print educational materials since both study arms used educational materials in the efficacy study friedman et al. [ ] random assignment not reported sample was predominately composed of african american female participants goldberg et al. [ ] random assignment no attrition reported ( %) study was completed at one clinical primary care setting site. study was completed only in one single year, so repeat fobt card return data were not collected holt et al. [ ] random assignment low attrition reported ( %) method of determining crc screening based on self-report. participation was not limited based on not being up-to-date with crc screening horne et al. [ ] random assignment low to medium attrition reported ( % in intervention arm; % in control arm) method of determining crc screening based on self-report. high percentage of participants were up-to-date at baseline myers et al. [ ] random assignment low attrition reported (< %) the sample was predominately composed of african american female participants. all participants were patients at primary care practices powe et al. [ ] quasi-experimental not reported the sample was predominately composed of african american female participants. there was a small sample size and -arm study design limited comparative analysis schroy et al. [ ] random assignment no attrition reported ( %) no blinding of providers to one of two intervention arms (decision aid plus personalized risk assessment or decision aid alone) with percentage point differences ranging from to % [ , , , ] . the outcomes for the three-arm studies testing variations of interventions in efficacy studies or testing two different variations of an intervention compared to controls, did not report markedly different findings from the two-arm studies. the study by arnold et al. [ ] was unique because it reported -year outcomes for stool blood testing, an outcome worth examining because of the recommendation for annual screening. except for the study by schroy et al. [ ] , the studies using experimental designs other than two-arm experimental designs had relatively small sample sizes. the study by schroy et al. [ ] reported that a decision aid improved overall crc screening rates, but did not report outcomes separately for stool blood testing. the study by christy et al. [ ] was particularly notable for the very high fit kit return of % of all participants, and the finding that prior screening status did not predict uptake. in this study, african american participants either received a fit kit plus a cdc standard crc screening educational brochure or fit kit plus a tailored photonovella, as well as reminder letters for those not returning the fit kit within a month-long timeframe, and both approaches were effective. two of the included studies, both three-arm studies, were identified as taking place in rural areas [ , ] . previous literature has found that the types of screening tests used for colorectal cancer may differ between rural and urban settings [ ] . screening rates by colonoscopy or sigmoidoscopy have increased in both rural and urban populations; however, screening rates via fobt have decreased in urban populations but increased in rural populations, possibly due to greater access to colonoscopy in urban areas and lack of access to colonoscopy services in rural settings [ ] . the results from the two included studies in rural areas reported increases in crc screening uptake, specifically fobt screening, which provides further support for the preference for fobt screening in rural areas. this systematic review included studies that implemented interventions in clinic or community settings. our results showed that the two-arm studies that were implemented in clinic-based settings had higher odds ratios than the two-arm studies implemented in community-based settings. based on these results, implementing crc screening interventions in clinic-based settings may lead to greater crc screening uptake among african americans than community outreach strategies outside of a clinical setting, possibly due to clinical interactions, audit and feedback systems, or other electronic means to remind patients of screening appointments. another finding in this systematic review indicated females were more likely to engage in fit and fobt, which is consistent with the results of studies examining stool based testing in articles that were eventually excluded after thorough review [ ] [ ] [ ] [ ] [ ] . however, in the included studies, there were larger samples of women than men, which might partially explain these findings, as well as highlight the challenges of recruiting african american men to cancer screening studies. the findings from this group of articles also suggests the promise of culturally tailored interventions to improve crc screening, such as the use of trusted community venues (e.g., churches, barber and beauty shops) to recruit participants and the implementation of patient navigation approaches to increase trust in providers. more research is needed to test effective interventions for increasing crc screening in minority communities and to test whether combined modalities or offering stool blood testing as a frontline strategy increases overall crc screening rates. unfortunately, some african american communities have higher levels of uninsured individuals, poor access to healthcare services, lower perceived benefits of crc screening, lower perceived risk of colorectal cancer, and lower engagement in preventive health behaviors [ , ] . the previously listed factors have also been cited as barriers for engaging minorities in crc screening [ , ] . in light of the economic burden of crc screening, utilizing fit and gfobt can provide a low-cost first-line screening test and be the deciding factor for medically underserved communities to engage in colorectal cancer screening [ ] . an examination of the studies in this review identified this frontline screening strategy with fit or gfobt can be cost effective. a previous study by hester et al. [ ] indicated stool blood testing presented fewer barriers for completion such as lack of transportation to the facility, bowel preparation, and absence from work, which may impede crc screening with colonoscopy. when the barriers to crc screening are removed, there is an opportunity to increase rates of screening among minority and non-minority groups. consistent with the literature, our findings indicated the feasibility and acceptability of fit and gfobt in african american communities as a primary screening strategy (baker et al. ; davis et al. ; rawl et al. ) . this systematic review focused on stool blood testing as one convenient method to increase crc screening in medically underserved communities. other studies using experimental designs reported similar findings but were excluded because of smaller african american patient samples [ , , ] . some identified studies employed other minority samples in their interventions. for example, the experimental study by muller et al. [ ] reported the effectiveness of the low-cost strategy of text messaging for increasing crc screening among alaska native patients. even though the current systematic review only included studies with a substantial representation of african american study participants, other studies examining diverse populations also reported the need for innovative interventions to increase crc screening in different community and clinical settings. based on the healthy people objectives, the target for adults between and years to receive crc screening was . %; however, data indicated only . % of adults had completed screening [ ] . this systematic review provides some evidence for future strategies to promote crc screening, especially for increasing the use of fobt among african americans. behavioral interventions may be more efficient if delivered through mail reminders or by using patient navigators. the content of such interventions should include tailored messages. if tailored materials are not available, a standard crc screening educational brochure may also be effective. for rural african americans, if primary care settings are not easily reachable, fobt may be a more accessible choice and preferable method to promote crc screening behavior. furthermore, the screening rates achieved by these interventions fall well short of the goal of % screening rate (by and in every community) proposed by the national colorectal cancer round table ( nccrt), which includes the american cancer society and the centers for disease control and prevention (cdc) [ ] . the rigor of the current systematic review lies in the methodology for the article search protocol pertaining to inclusion criteria (e.g., type of study design, peer-reviewed studies in scientific journals, presence of comparison groups) and search strategy. however, some studies may not have been included in the initial search because of the particular search terms used or article indexing procedure that may have excluded an article from the search. the included studies varied in study quality. seven of the studies included randomization of study participants, and five of the studies were randomized controlled trials. because of variations in reporting study findings and not stratifying by screening modality, for a few studies it was not possible to isolate the effect of the stool blood testing method. it is recommended that screening outcomes are disaggregated in the reporting of study outcomes. a meta-analysis was not possible for this review because of the heterogeneity in study designs and reported outcomes. some studies did not report odds ratios so the decision was made to calculate odds ratios for all studies based on the data presented in each article. a systematic review of u.s.-based crc screening interventions reported that crc screening interventions which include a combination of screening methods might be most effective; however, most clinic-based interventions might need to provide the array of screening options if they are part of their menu of services [ ] . some clinics, such as federally-qualified health centers (fqhc), might only provide stool blood testing and referral to colonoscopy, so these types of clinics would be more likely to be study sites for a stool blood testing approach only. future reviews might include all stool blood testing interventions regardless of population served to determine preferences in actual clinical practice settings to test whether they may be differences by geography or racial group. the option to choose stool blood testing is part of a comprehensive cancer education approach to increase crc screening. our findings align with the healthy people objective, which seeks to increase colorectal cancer screening based on current guidelines. recent guidelines from leading medical and community health organizations (i.e., united states preventative task force, the american cancer society, the american academy of family physicians, and task force on community preventive services) recommend the use of stool blood testing for colorectal cancer screening, ideally leading to early detection and a reduction in mortality rates [ , ] . the low-cost and decreased barriers compared to colonoscopy (e.g., time off work, access to a medical facility, and transportation) might provide an opportunity for some minority populations experiencing crc disparities to increase participation in screening. however, without sufficient knowledge of these tests and the recommended screening intervals for such screening, minority communities cannot receive the full benefits of crc cancer prevention. strategies to increase stool blood testing in african americans include standard mailed blood stool tests augmented by patient navigation, tailored educational materials, and follow-up calls or mailings to increase trust in the patient-provider relationship. to increase overall crc screening in african americans also requires decreasing barriers to access for preventive screenings by increasing insurance coverage and lowering out of pocket healthcare costs. cancer statistics for african americans cancer statistics clinical and genetic factors to inform reducing colorectal cancer disparitites in african americans toward the elimination of colorectal cancer disparities among african americans screening for colorectal cancer: us preventive services task force recommendation statement standardized workflows improve colonoscopy followup after abnormal fecal immunochemical tests in a safety-net system colorectal cancer screening patterns after the american cancer society's recommendation to initiate screening at age years colorectal cancer screening: recommendations for physicians and patients from the u.s. multi-society task force on colorectal cancer american college of gastroenterology guidelines for colorectal cancer screening exploring perceptions of colorectal cancer and fecal immunochemical testing among african americans in a 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americans: screening and theory-based outcomes from a randomized trial effect of patient navigation on colorectal cancer screening in a community-based randomized controlled trial of urban african american adults. cancer causes and control increasing colon cancer screening in primary care among african americans an intervention study to increase colorectal cancer knowledge and screening among community elders aidassisted decision making and colorectal cancer screening: a randomized controlled trial systematic review of mammography screening educational interventions for hispanic women in the united states urban-rural disparities in colorectal cancer screening: cross-sectional analysis of - data from the centers for disease control's behavioral risk factor surveillance study fobt completion in fqhcs: impact of physician recommendation, fobt information, or receipt of the fobt kit colorectal cancer screening among low-income african americans in east harlem: a theoretical approach to understanding barriers and promoters to screening increasing colorectal cancer screening at an urban fqhc using ifobt and patient navigation a randomized controlled trial of the impact of targeted and tailored interventions on colorectal cancer screening a randomized trial of two print interventions to increase colon cancer screening among first-degree relatives. patient education and counseling the cascade of social determinants in producing chronic disease in low-income african-american men male role norms, knowledge, attitudes, and perceptions of colorectal cancer screening among young adult african american men the role of perceived benefits and barriers in colorectal cancer screening in intervention trials among african americans decisional stage distribution for colorectal cancer screening among diverse, low-income study participants implementation intentions and colorectal screening: a randomized trial in safety-net clinics text message reminders increased colorectal cancer screening in a randomized trial with alaska native and american indian people along the way to developing a theory of the program: a re-examination of the conceptual framework as an organizing strategy creating and implementing a national public health campaign: the american cancer society's and national colorectal cancer roundtable's % by initiative a systematic review of u.s.-based colorectal cancer screening uptake intervention systematic reviews: available evidence and lessons learned for research and practice recommendations for client-and provider-directed interventions to increase breast, cervical, and colorectal cancer screening colorectal cancer screening and prevention spiritually based intervention to increase colorectal cancer awareness among african americans: intermediate outcomes from a randomized trial publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations key: cord- -mpv wegm authors: peng, kerui; safonova, yana; shugay, mikhail; popejoy, alice; rodriguez, oscar; breden, felix; brodin, petter; burkhardt, amanda m.; bustamante, carlos; cao-lormeau, van-mai; corcoran, martin m.; duffy, darragh; guajardo, macarena fuentes; fujita, ricardo; greiff, victor; jonsson, vanessa d.; liu, xiao; quintana-murci, lluis; rossetti, maura; xie, jianming; yaari, gur; zhang, wei; lees, william d.; khatri, purvesh; alachkar, houda; scheepers, cathrine; watson, corey t.; hedestam, gunilla b. karlsson; mangul, serghei title: diversity in immunogenomics: the value and the challenge date: - - journal: nan doi: nan sha: doc_id: cord_uid: mpv wegm with the recent advent of high-throughput sequencing technologies, and the associated new discoveries and developments, the fields of immunogenomics and adaptive immune receptor repertoire research are facing both opportunities and challenges. the majority of immunogenomics studies have been primarily conducted in cohorts of european ancestry, restricting the ability to detect and analyze variation in human adaptive immune responses across populations and limiting their applications. by leveraging biological and clinical heterogeneity across different populations in omics data and expanding the populations that are included in immunogenomics research, we can enhance our understanding of human adaptive immune responses, promote the development of effective diagnostics and treatments, and eventually advance precision medicine. analyses . this limits the discovery of genetic diversity contributing to mendelian diseases and to explore associations between genetic variants and trait variation across populations. in recent years, awareness has been increasing about the limited generalizability of findings across populations, motivating the inclusion of diverse, multiethnic populations in large-scale genomic studies , . for example, novel single nucleotide polymorphisms (snps) that are clinically associated with warfarin dosing were discovered in large scale genomics studies in individuals of african descent that had not been discovered in europeans , . whole-genome sequencing in individuals of african descent [ ] [ ] [ ] and whole-exome sequencing in a southern african population additional efforts have been made through international collaborations to establish reference genome datasets and recommendations for research in diverse populations; including the genomeasia k project, the human heredity and health in africa (h africa) initiative, and the clinical genome resource (clingen) ancestry and diversity working group (adwg) [ ] [ ] [ ] [ ] . khatri and colleagues discovered the -gene signature for diagnosis of tuberculosis based on transcriptome profiles of participants from countries , a finding that was generalized to patient populations from every inhabited continent in a span of years , . most importantly, the -gene signature has been clinically translated to the point-of-care test by cepheid . the inclusion of diverse populations in genomic studies has demonstrated benefits in the discovery and interpretation of gene-trait associations. similarly, greater diversity in immunogenomics research will enable the discovery of novel genetic traits associated with immune system phenotypes that are common across populations. broader inclusion of diverse populations may also enable researchers to address genetic heterogeneity in the context of translational research and clinical drug development, possibly revealing clinically relevant genomic signatures that are more prevalent in some populations than others. immunogenomics is a field in which genetic information at different levels of biological organization (epigenetics, transcriptomics, metabolomics, cells, tissues, and clinical data) has been characterized and utilized to understand the immune system and immune responses. here table ). rna-seq has traditionally been mapped to study entire cellular populations instead of amplifying at the specific regions. given the complexity of the tcr and bcr genomic loci, the accurate determination of germline immune receptor genes, from bulk rna-seq or whole-genome sequencing, has proved challenging . several computational methods show promise [ ] [ ] [ ] , but the mapping rate and accuracy remain to be improved. additionally, a wide-scale comparison is needed between results obtained from methods for deriving germline receptor genes from rnaseq studies, those obtained from established methods such as, targeted pcr and sequencing of genomic dna, the sequencing and assembly of bacterial artificial chromosome (bac) and fosmid clones , and those from more recent methods such as inference from airr-seq repertoires . many population genetic differences have been observed in genomics studies and immunogenomics is no exception [ ] [ ] [ ] . the current public databases of adaptive immune receptor germline genes are essential for airr-seq analysis and immunogenomics studies. however, the most widely used reference database for immunogenetics data, the international immunogenetics information system (imgt) , lacks a comprehensive set of human tcr and bcr alleles representing diverse populations worldwide. the same issue exists in hla databases: over % of rare hla variants from oceania and west asia populations were found to be absent in the genomes project panel . there is still more uncertainty due to the fact that descriptions of sample populations in databases are often self-identified based on geography or ethnicity, rather than genetic ancestry. however, progress has been made to address this issue in immunogenomics studies. for example, the airr community, an international community formed to promote high standard research in adaptive immune repertoire research, introduced the open germline receptor database (ogrdb) in september as a resource platform for germline gene discovery and validation from airr-seq data, to enrich the imgt database . collaborators in our team also created vdjbase, a platform for the inferred genotypes and haplotypes from airr-seq data . these efforts provide the opportunities to infer genetic ancestry. nevertheless, the majority of available germline sequences either lack population-level annotations or are biased toward samples of european descent. we argue that this shortcoming must be addressed through focused efforts that seek to include more diverse populations in immunogenomics research. as an interdisciplinary group, with expertise in biomedical and translational research, population biology, computational biology, and immunogenomics, we wish to raise awareness about the value of including diverse populations in airr-seq and immunogenetics research. in the areas of genetic disease research and cancer genomics, enhanced genetic diversity has led to demonstrable insights , . however, the field of immunogenomics has yet to benefit from a similar growth in diversity. at the current stage of the global covid- pandemic, numerous vaccine trials are underway in many countries worldwide, offering opportunities to investigate genetic factors in vaccine responses. yet, this will require careful clinical study designs that can effectively address confounding factors such as environmental and socio-economic differences. hiv- , zika , and sars cov- . we expect that vaccine and infection outcomes can also be shaped by genetic variability, including specific effects driven by immune-related genes . here, we make several recommendations for increasing diversity in immunogenomics research. first, we propose that the community should make a greater effort to include underrepresented populations in airr-seq and immunogenomics studies. already, those that have conducted airr-seq in populations of non-european descent have uncovered evidence for extensive germline diversity. for example, in a study of south african hiv patients, scheepers and colleagues discovered ighv alleles that were not represented in imgt . this promoted the hiv vaccine design by understanding the immunoglobulin heavy chain variable region (ighv) profile in the south african population. in a study in the papua new guinea population, one novel ighv gene and ighv allelic variants were identified from airr-seq data . these discoveries of novel alleles indicate the need to generate population-based airr-seq datasets. we do not recommend generalizing airr-seq findings to populations that are underrepresented in research, due to missing variation and lack of validation, which limits our ability to leverage airr-seq datasets in biomedical applications.therefore, increasing population diversity in immunogenomics studies can lead to improvements in a wide range of applications, including drug discovery and development, vaccine design and development. promoting precision medicine for underrepresented populations and improving predictions for treatment outcomes will become more feasible in the future with broader participation and inclusion. second, we argue that there are existing genomic datasets that could potentially be leveraged to augment ig/tcr germline databases, and inform the interpretation of airr-seq and immunogenomics studies across populations. extraction of population immunogenomics information from existing genomic datasets could be an effective strategy, as well as carefully embracing non-targeted sequencing data (eg. rna-seq) to focus on genetic diversity of samples. ancestry-associated genetic markers in short-read genome sequencing may help overcome the difficulties of relying on sample metadata in airr-seq datasets. this may also be time-efficient relative to waiting for the availability of sufficiently diverse airr-seq datasets. researchers have attempted to utilize paired-end rna-seq data in the cancer genome atlas (tcga) to infer the complementarity determining region (cdr ) of tumor-infiltrating t-cells , and to apply a computational method to rna-seq data in the genotype-tissue expression consortium (gtex) to profile immunoglobulin repertoires . similar ideas could be adapted to the direct prediction of allelic variants from short-read genomic sequence data , . however, challenges need to be overcome, including the high levels of copy number variation and segmental duplication in the bcr and tcr loci, and the need for protocols to validate novel allelic variants gleaned from short-read sequencing data , finally, we suggest the need for additional infrastructure and expertise in regions and countries with populations underrepresented in research, and to enhance collaborations between countries, which are critical in minimizing global health disparities. online training sessions that are customized for conducting immunogenomics research in diverse populations would be beneficial to the biomedical community, perhaps especially in those regions. the content of these trainings might include participant recruitment strategies with a commitment to outreach and education to increase participation, sample collection methods, steps to running sequence experiments onsite or in collaboration with other academic institutions or commercial companies, uploading sequencing data to appropriate repositories, and performing bioinformatics analyses. virtual learning platforms for bioinformaticians have been established by members in our group, and these could be leveraged to provide such trainings . our interdisciplinary group consists of leading researchers from countries, including the us, canada, norway, france, sweden, russia, the uk, israel, china, south africa, chile, peru, and french polynesia. we share concerns about the lack of diversity in immunogenomics and embrace the need for engaging our combined efforts to tackle this challenge. to spearhead the enterprise of fostering diversity in the field, we have formed this task force with the aim of developing a global consortium on diversity in immunogenomics. this consortium will seek 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immune receptor gene families in humans correction: a database of human immune receptor alleles recovered from population sequencing data comment on 'a database of human immune receptor alleles recovered from population sequencing data living in an adaptive world: genomic dissection of the genus homo and its immune response how bioinformatics and open data can boost basic science in countries and universities with limited resources diseases of the national institutes of health under award number u ai .we thank dr. nicky mulder for the valuable comments that greatly improved the manuscript. key: cord- - ughypnx authors: louis-jean, james; cenat, kenney; njoku, chidinma v.; angelo, james; sanon, debbie title: coronavirus (covid- ) and racial disparities: a perspective analysis date: - - journal: j racial ethn health disparities doi: . /s - - - sha: doc_id: cord_uid: ughypnx health disparity refers to systematic differences in health outcomes between groups and communities based on socioeconomic isolation. in the usa, health disparities among minority groups, especially african americans, limit their access to quality medical care and other beneficial resources and services. presently, the novel coronavirus (covid- ) highlights the extreme healthcare challenges that exist in the african american and other minority communities in the usa. african americans are dying at a rate nearly four times higher than the national average. with inadequate access to quality healthcare, viable resources, and information, covid- will continue to have a disastrous effect on african american communities. this communication provides a brief overview of the health inequalities resulting in african americans dying disproportionately during the covid- pandemic. the novel coronavirus (covid- ) emerged from wuhan, china, in late and quickly became a global pandemic that has already affected more than countries and territories [ ] . in symptomatic patients, this highly transmissible disease causes severe acute respiratory syndrome, which infects lower respiratory airways and results in fatal pneumonia. the effect of this pandemic is widely visible, resulting in about a . % mortality rate and causing major economic and social devastations [ ] . studies have shown that covid- is transmitted via human interactions when uninfected individuals come in contact with mucus and respiratory droplets or surfaces that contain the virus. on surfaces where it is present, the virus can remain infectious from hours and up to days depending on the surface materials. also, it can remain airborne for up to hours post aerosolization [ ] . furthermore, a small majority of carriers develop mild to no symptoms. as a result, transmission occurs rapidly and inconspicuously with both symptomatic and asymptomatic individuals unknowingly transmitting the virus, resulting in more people being infected. research data continues to show that covid- affects all age groups. older individuals and those with underlying health conditions are more prone to experiencing severe illnesses and death. data analysis of covid- from the usa highlights pre-existing health disparities among african americans as the potential cause of poor prognosis. based on reports from national health care disparities, in comparison with non-hispanic whites, african americans have a % greater chance of dying from stroke, % more likely to have asthma, % more likely to have heart disease, % more likely to have diabetes, and % more likely to be obese [ ] . this is a major concern that government and public health officials should address as it has been shown that in out of states reporting data, black people accounted for a higher share of covid- cases than their share in the population [ ] . in out of states, they accounted for a higher share of deaths than their share of the total population [ ] . in such regard, an immediate plan of action is urgently needed to address and mitigate the effects of health disparities. this communication briefly examines the health disparities among african americans in the usa during the covid- pandemic. in the early phase of the outbreak in the usa, access to testing was limited to government officials, celebrities, and a selected number of healthcare workerssymptomatic or asymptomatic. it was not until march when the federal government passed the families first coronavirus response act (ffcra), which allows free covid- testing for all individuals [ ] , that large-scale testing became available nationwide. while ffcra is a great response for all citizens, the lack of testing remains, especially in minority communities. in the usa, the racial breakdown of covid- cases and deaths is now starting to be made available. in louisiana, where % of its population is african american [ ] , % of deaths-as a result of the novel coronavirus-are among african americans. meanwhile, white americans in louisiana account for % of the population but recorded only % of covid- deaths [ ] . of the covid- deaths in illinois [ ] , the percentage of deaths among black americans ( %) is higher compared with those among whites ( %), hispanics ( . %), asians ( . %), and others ( . %). this is an area where the majority of the population is white ( %) and the black population is about %. the same phenomenon is occurring in michigan [ ] ; the black population is about % but accounted for % of covid- deaths. in new york, both hispanics and african americans are dying at a relatively higher rate in comparison with other ethnic groups. they account for % and % of new york's population, respectively. however, the reported death toll [ ] for hispanics and african americans is % and %, respectively. in connecticut, the black population is about %, but represents more than % of covid- deaths [ , ] . in milwaukee county, the black population is about % but represents % of covid- deaths [ , ] . in north carolina, % of deaths are among african americans, who represent % of the total population [ ] . the trend and commonality transcend state lines. the common denominator for the high mortality rate in all these states is race and ethnic background. of note, all data presented in this communication and fig. are subject to change as more data becomes available. for more up-to-date data, refer to the states department of public health and services. a recent study showed that in zip codes with high numbers of unemployed and uninsured residents, fewer test kits were available [ , ] . most of those zip codes have disproportionate numbers of african americans. it is no surprise that underserved communities such as the african american communities would also have less access to covid- test kits in a time that kits are scarce. assuming that african americans are seeking medical attention for covid- , they will most likely do so at minority-serving institutions which already have [ ] : (i) lower quality care due to low budgets and lack of resources (ii) shortage of critical care physicians (iii) inadequate number of medical supplies and equipment (i.e., personal protective equipment and ventilators for critically ill patients). this is in parallel to years of ongoing racial and socioeconomic discrimination in the usa [ , ] . while a series of landmark court cases such as simkins v moses h. cone memorial hospital ( ) and cypress v newport news hospital association ( ) litigated by the national association for the advancement of colored people (naacp) legal defense and education fund took legal actions against racial policies and discriminations in healthcare, the challenges for quality healthcare for african americans remain [ ] . the pursuit of legal strategies against racist policies was an essential element in a national campaign to eliminate discrimination in healthcare delivery in the usa. as covid- cases and related deaths continue to rise in the usa, data demonstrates that african american communities in various cities are the most affected ( fig. ). this is a challenge that the federal government and its covid- task force have pointed out. however, in a white house press briefing, dr. anthony fauci of the national institute of allergy and infectious diseases recently expressed, "…there is nothing we [the federal government] can do about it right now except to give them [african americans] the best possible care to avoid complications." health disparities and institutional racism [ , , [ ] [ ] [ ] [ ] [ ] ] make the covid- pandemic worse for african americans. there are studies on the effects of stress and health for african americans as stress can increase vulnerability, which in turn is a factor in determinants of health disparities. perceived discrimination can add to stress, which increases vulnerability to the health effects of environmental hazards, thus adding to health disparities. harburg et al. highlighted that darkerskinned black men having racist interactions and living in neighborhoods with high rates of social instability have an increased risk and incidence of stressful experiences in daily life, which in turn increases their likelihood of high blood pressure along with other health conditions they are predisposed to from their environment [ ] . conditions resulting from these conditions are listed as risk factors for more severe covid- cases [ ] . constant streams of statistical data (fig. ) about the novel coronavirus are showing that african americans are dying from covid- -related complications at a disproportionately higher rate than other ethnic and racial groups. racial inequities in healthcare institutions, lack of access to information, higher levels of preventable chronic diseases (i.e., diabetes, asthmas, hypertension, etc.), and covid- testing not being widely available in minority communities are among the many factors resulting in african americans dying at disproportionate numbers during this pandemic [ ] . failure to rapidly test and segregate individuals infected with covid- can result in major chain-of-transmission reactions and deaths. the socioeconomic discrimination has confined african americans to overpopulated housing estates (ghettos) and low-wage jobs. from the very genesis of this country, african americans have always been the essential or sacrificial workers used to ensure the continuity of this economy. from centuries of free slave labor to years of sharecropping to low-paying domestic jobs, african americans have always played a role in shaping the very essence of what america is [ , ] . today, a large number of african americans work in retail, home healthcare, mass transit, plant factories, and prisons/jails where social distancing is almost impossible. as a result, african americans became more vulnerable to the disease combined with inadequate access to proper healthcare in their communities [ ] . in many cities in the usa, stay-at-home orders are placed to mitigate the spread of the virus. this is a great effort, which has shown promising results. however, african americans and other minority groups account for % of the us homeless population [ ] . these individuals stand no chance against the trail of devastation that covid- will leave behind since it is almost impossible for them to follow preventative guidelines issued by the centers for disease control and prevention (cdc) and government officials. to help flatten the curve, many doctors, nurses, and other healthcare professionals from non-profit organizations are volunteering their services to the homeless community. among other preventative measures highlighted by the cdc as well as healthcare and government officials is the use of face masks in public settings. while this effort can limit and reduce the spread of covid- , this could pose a challenge to african americans and other minorities as they are more likely to be criminalized based on their appearances while wearing masks. of note, many individuals have failed to understand the zoonotic origin of covid- [ ] [ ] [ ] [ ] . as a result, significant misinformation and conspiracy theories continue to circulate on the web and social media. while the internet is an open platform to share and access information, individuals should be aware of conspiracy theories and follow credible sources for relevant information. while there is no evidence showing a correlation between covid- and the upcoming fifthgeneration ( g) technology, people continue to share misinformation linking the current pandemic to g technology. initially, there was the belief that black individuals and minorities were not susceptible to being infected with the virus. there is no available research showing that black individuals are biologically and genetically immune to the virus. without proper information, these artificial assumptions can usher individuals into disastrous directions. on a global scale, covid- is not only affecting people of african descent in the usa but across the world. minority groups everywhere are harassed and discriminated against during this pandemic. in china where the virus emerged, africans living in guangzhou are being evicted from their homes as the virus sparked fear and racial discrimination. of equal challenges, minorities and migrant workers from caribbean countries, such as haiti, living in the usa are being detained by the immigration and customs enforcement (ice) at detention centers where the virus is uncontrollable. these haitians-some of whom are infected with or are covid- carriers-are subjected to deportation to their native land of haiti, a country with a very weak public healthcare system [ ] . only a few examples are highlighted here; a comprehensive analysis is underway. altogether, african americans and individuals of african descent are more vulnerable to the impact of the virus. it is no secret that the us government has misguided and often used african americans as guinea pigs for medical research. during the time of slavery, psychologists and doctors deemed it a disease for slaves to long for freedom or want to "run away." runaway slaves were diagnosed with what was called "drapetomania," which was considered, at the time, a mental illness that amplifies the desire to become a fugitive-run away [ ] . furthermore, after slaves were freed, many american doctors continued to argue that former slaves were incapable of thriving as free members of society because their minds could not function beyond the established orders of slavery. among many other diseases, the syphilis outbreak in the south highlighted another dark chapter in african americans' relations with the healthcare system in america. many african americans infected with syphilis were promised treatment from the public health department. instead, those patients were denied treatment and turned into "guinea pigs" to monitor the progression of the disease. the patients were unaware and were lied to repeatedly about their conditions. many of those untreated "guinea pigs" of the syphilis experiment infected their wives and other women they had gotten in contact with. furthermore, many of them had unknowingly fathered children born with congenital syphilis. the syphilis experiment lasted for years, and it was a major ethical violation. the us government had broken its laws and experimented on its citizens. the us public health service did not treat the people who were experimented on even after penicillin-the effective cure for the disease-was made available. historically, this injustice has established a certain level of distrust among african americans in the us public health system; therefore, they are more reluctant in seeking routine preventative care [ ] . the time for a healthcare revolution for african americans is long overdue. this is not a surprise, as years ago, the flu pandemic highlighted the racial bias and distrust that existed in the medical community [ , ] . jim crow laws and pseudoscientific theories made the impact of the flu go unnoticed in black communities. all efforts and resources were made available to white communities as physicians believed that the virus only affected white individuals. many healthcare officials, with no reliable scientific evidence, believed that african americans were not susceptible to the flu as the linings of their "big noses" were resistant to the microorganism that affects the respiratory system. as a result, black communities were forced to battle the flu pandemic on their own, using limited resources and inadequate medical care at segregated healthcare institutions [ ] . the current covid- pandemic reflects a mirror image of the flu pandemic for african americans and other minorities in the usa [ ] . such patterns will possibly continue if the socioeconomic, health disparities, and the dividing racial lines stretch to upcoming generations. other jurisdictions have yet to publicly report their data based on race and ethnicity; regardless, the challenges remain from social and economic factors that drive health outcomes. altogether, african americans are dying at a much higher rate compared with any other ethnic group. due to various factors that affect health outcomes, a plan of action is urgently needed to respond to the challenges of this pandemic and any health threats in african american communities [ ] . access to testing and proper medical treatment is necessary to ensure the safety of african americans, the most vulnerable group. the embedded racism in the healthcare system and the socioeconomic and health disparities [ , ] continue to make the effect of the virus worst-for black americans and other minorities in the usa. overall, the lack of testing made available to the black community for covid- , the continuous poor healthcare system for african americans, and the systematic health disparity are what makes this virus more dangerous to african americans; although covid- is a new pandemic, it is deeply rooted in history in the continuous plight of african americans in this country [ ] . it is an unsettling reality for african americans to rely on the same systems that historically inflicted harm and damage on them to protect and serve them against this virus [ , , ] . more research is needed to understand the source of exposure to covid- for african americans as well as a plan of care and health outcomes of african americans in various zip codes. further research can also shed light into the type of facilities a majority of african americans receive care in, such as nursing homes, and assess their preparedness looking into their access to resources such as personal protective equipment (ppe) during the covid- pandemic, current and past documented deficiencies from state surveys, and infection control measures taken during covid- , and overall health outcome. more research is also needed to understand how the environment affects health outcome or the severity of covid- cases in terms of environmental exposures, social, and economic factors that can affect mortality, morbidity, life expectancy, healthcare expenditures, and health status amidst the covid- pandemic. this is relevant since a recent study found that living in areas with high air pollution is associated with an % increase in the covid- death rate [ ] . black leaders in all communities, historically black colleges and universities (hbcus), and minority-serving institutions (msis) should continue to engage and educate students to respond to the needs of their communities. this will require these institutions to reinvent and alter their curriculums to provide more health and medical programs (including medical history), engineering, science, and technology. currently, these institutions are operating with low resources, many are underfunded, and others are on the verge of being permanently closed. this is very unfortunate for african americans and other minority communities especially when analyzing the impact of covid- . as the pandemic forced all teaching to be done remotely, hbcus' and msis' students and institutions are at higher risks of not being able to satisfy their educational needs [ ] . many have limited to no access to technological devices and reliable internet access to fully respond to the spontaneous remote teaching caused by the effect of the virus. the gravity of the novel coronavirus covid- (sars-cov- ) pandemic is yet another event showing the racialized health inequalities that exist in the usa. african americans have systematically experienced the worst health outcomes compared with any other racial and ethnic group in the usa. the burdens of covid- are much greater among minorities living in low-income communities where access to quality healthcare and other relevant needs is scarce. the health disparities in the usa did not start with the covid- pandemic. however, the virus has significantly highlighted the pre-existing racial inequalities. altogether, the socioeconomic status and the well-being of african americans require intervention and significant improvement is needed. this will require mutual inclusions of community leaders from various organizations (i.e., churches, divine nine organizations: fraternities and sororities), local government, policymakers, and researchers to mend healthcare in low-income communities. ethics approval and consent ethical approval or consent was not applicable for this paper. the authors declare that they have no conflict of interest. world heal. organ on the novel coronavirus (covid- ): a global pandemic persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents national surveillance of asthma: united states growing data underscore that communities of color are being harder hit by covid- louisiana state dep. heal. coronavirus disease (covid- ) in illinois test results. illinois state dep. public heal. public heal. . https:// covid tracker.health.ny.gov/views/nys-covid -tracker/ nysdohcovid- tracker-fatalities?% aembed=yes&% atoolbar=no&% atabs=n connect. state dep. public heal. the covid- pandemic: a call to action to identify and address racial and ethnic disparities covid- : county data. wisconsin state dep covid- north carolina dashboard. north carolina state div. public heal the black plague. new yorker. coronavirus philadelphia: positive tests higher in poorer neighborhoods despite six times more testing in higher-income neighborhoods, researcher says. cbs philly temporal trends in critical care outcomes in u.s. minority-serving hospitals social conditions as fundamental causes of health inequalities: theory, evidence, and policy implications racial and ethnic approaches to community health (reach ): an overview professional and hospital discrimination and the us court of appeals fourth circuit - social conditions as fundamental causes of disease the weathering hypothesis and the health of african-american women and infants: evidence and speculations the us perspective: lessons learned from the racial and ethnic approaches to community health (reach) program limitations in the use of race in the study of disease causation seeking causal explanations in social epidemiology socio-ecological stress, suppressed hostility, skin color, and black-white male blood pressure: detroit preliminary estimates of the prevalence of selected underlying health conditions among patients with coronavirus disease -united states vital signs: racial disparities in age-specific mortality among blacks or african americans -united states at the dark end of the street: black women, rape, and resistance-a new history of the civil rights movement from rosa parks to the rise of black power from slavery to freedom: a history of african americans who is homeless? natl. coalit. homeless coronaviruses: a paradigm of new emerging zoonotic diseases. pathog dis novel coronavirus takes flight from bats? bats as a continuing source of emerging infections in humans dbatvir: the database of batassociated viruses covid- ) in haiti: a call for action tuskegee and the health of black men african americans, public health, and the influenza epidemic the eighteen of - : black nurses and the great flu pandemic in the united states covid- and african americans why african-americans may be especially vulnerable to covid- exposure to air pollution and covid- mortality in the united states: a nationwide cross-sectional study beyond the face-to-face learning: a contextual analysis publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations acknowledgments thanks are due to miriame etienne, ruthonce stvil louis-jean, isaiah herbert, and magdonald aimé for their feedback.data availability all materials and data used in this communication are publicly available and are cited throughout the text. key: cord- -f jdbv authors: longino, kevin; kramer, holly title: racial and ethnic disparities, kidney disease, and covid- : a call to action date: - - journal: kidney med doi: . /j.xkme. . . sha: doc_id: cord_uid: f jdbv nan kevin longino, mba, holly kramer, md, mph as the nation once again turns its attention to the black lives matter movement, we must ask ourselves how the movement applies to our community of kidney patients and the professionals who care for them. the fact that the call for racial justice is occurring in the midst of a public health epidemic is not a coincidence. the same factors that have spurred nationwide protests -poverty, inequality, implicit bias, and systemic racism -contribute to the disproportionate impact that kidney disease has on communities of color. while the national kidney foundation (nkf) alone cannot end the + year legacy of racism that affects the day-to-day lives of so many patients, we hear our moral calling to look the challenge square in the eye. it is incumbent upon all of us -as healthcare professionals, patients, and advocates -to confront racial and ethnic disparities and work together to ensure that all people with kidney disease receive nothing but the best care our system has to offer. covid- is the most significant health crisis in the modern era. it has directly and indirectly resulted in overwhelming rates of illness and death, has created major disruptions to economies and everyday life both in the united states and throughout the world, and might leave survivors with chronic, permanent health complications. notably, severe covid- has been associated with acute kidney injury (aki), which can increase the risk of chronic kidney disease (ckd) over time. , ckd has also been associated with more severe covid- infection. , covid- has had devastating and disproportionate consequences for communities of color. people of african american, american indian or alaska native american descent are five times more likely to be hospitalized due to covid- than whites, while hispanics are approximately four times more likely to be hospitalized. one in four americans dying of covid- are black or african american, even though members of this community represent only percent of the us population. the reasons for these unconscionable disparities are multifactorial but are likely closely tied to social determinants of health such as access to healthcare, socioeconomic status (ses), employment, food security, education, housing, environment, and social support. these factors in turn have been driven and exacerbated by a long history of systemic racism. some specific factors can include the higher likelihood of living in densely populated areas or in crowded housing conditions; being an essential worker who cannot work remotely; and relying on a job with a lower income or without sick leave. another significant disparity is a lack of access to healthcare, as hispanics are about three times as likely to be uninsured, and black or african americans are almost twice as likely to be uninsured. many of the healthcare and socioeconomic disparities that make communities of color more vulnerable to covid- also make them vulnerable to kidney disease. communities of color often have higher rates of diabetes and high blood pressure, which are the first and second leading causes of kidney failure, respectively. the risk of ckd increases for black or african american patients compared to white patients at every stage. early referral to nephrology is associated with improved ckd outcomes, however black or african american patients are more likely to have delayed referral or no nephrology referral at all. communities of color are also overrepresented among patients with end-stage kidney disease. for every three non-hispanics who develop kidney failure, four hispanics develop kidney failure. black or african americans are three times more likely to suffer from kidney failure than whites. these disparities extend into treatment modalities as well. black and hispanic patients are less likely to receive home dialysis, and when they do begin peritoneal dialysis (pd), they are more likely to fail within the first days. black or african american patients have less access to the optimal treatment of kidney transplantation. they are less likely to be waitlisted for an organ, and when they are transplanted, they wait longer, are less likely to receive a deceased or living donor organ (i.e., die on the waitlist) and have poorer graft survival at first year post-transplant. in an effort to address these challenges, nkf is advocating for access to affordable healthcare, to increase our federal investment in research, prevention, and innovations in care for people with kidney disease, and to ensure that racial and ethnic communities are not left behind. the issues that underlie kidney disease, covid- , and healthcare disparities are complex. however there are some specific strategies nkf is advocating, including calling on the federal government to provide quality, disaggregated data on all tests, hospitalizations, discharges, and deaths from covid- in order to fully understand the scope of the problem; and to ensure priority testing, contact tracing, access to a future vaccine, and funding for high-risk and minority communities and kidney patients. nkf also supports long-term investments in public health infrastructure in historically underserved communities and increased funding for kidney disease research and awareness. the nkf and the american society of nephrology (asn) established a joint task force to reassess the inclusion of race in diagnosing kidney disease. the task force aims to evaluate the use of race in calculating egfr and ensure that gfr estimation equations provide an unbiased assessment of kidney function so that laboratories, clinicians, patients, and public health officials can make informed decisions to ensure equity and personalized care for patients with kidney disease. this work is important, but it alone cannot solve the many health and socioeconomic disparities facing black or african american and other minority communities, which are rooted in historical and ongoing systemic racism. however, this work can make progress towards addressing healthcare disparities that continue to fuel disenfranchisement among these communities. the nkf is also advocating to address areas of concern for people with kidney disease in the context of the covid- pandemic, including prioritizing kidney patients' and clinicians' access to personal protective equipment; preserving access to essential kidney-related surgical procedures (e.g., organ transplantation, vascular access); and fighting policies that discriminate against kidney patients. the nkf is also working with several partners to implement policies that accelerate patients' access to home dialysis; ensure timely implementation of kidney care payment models; ensure kidney patients and transplant patients can access greater-than- -day supplies of critical prescriptions including immunosuppressive drugs; and ensure that vulnerable home dialysis, transplant patients, and living donors can receive needed blood draws in their homes. acute kidney injury in patients hospitalized with covid- kidney disease is associated with in-hospital death of patients with covid- chronic kidney disease is associated with severe coronavirus disease (covid ) infection covid- in racial and ethnic minority groups chronic kidney disease in the united states the nkf will continue work that is tangible, results-focused, and lifesaving. the nkf will also continue long-term and focused outreach to our black or african american patients and all patients of color who develop kidney disease and the devastating complications which accompany it. key: cord- - l mk authors: clark, ian a.; griffiths, michael j. title: the molecular basis of paediatric malarial disease date: journal: pediatric infectious diseases revisited doi: . / - - - - _ sha: doc_id: cord_uid: l mk severe falciparum malaria is an acute systemic disease that can affect multiple organs, including those in which few parasites are found. the acute disease bears many similarities both clinically and, potentially, mechanistically, to the systemic diseases caused by bacteria, rickettsia, and viruses. traditionally the morbidity and mortality associated with severe malarial disease has been explained in terms of mechanical obstruction to vascular flow by adherence to endothelium (termed sequestration) of erythrocytes containing mature-stage parasites. however, over the past few decades an alternative ‘cytokine theory of disease’ has also evolved, where malarial pathology is explained in terms of a balance between the pro- and anti-inflammatory cytokines. the final common pathway for this pro-inflammatory imbalance is believed to be a limitation in the supply and mitochondrial utilisation of energy to cells. different patterns of ensuing energy depletion (both temporal and spatial) throughout the cells in the body present as different clinical syndromes. this chapter draws attention to the over-arching position that inflammatory cytokines are beginning to occupy in the pathogenesis of acute malaria and other acute infections. the influence of inflammatory cytokines on cellular function offers a molecular framework to explain the multiple clinical syndromes that are observed during acute malarial illness, and provides a fresh avenue of investigation for adjunct therapies to ameliorate the malarial disease process. although many species of malarial parasite exist, only plasmodium falciparum, vivax, ovale, and malariae are classically associated with human infection. the former two species are most frequently associated with malarial disease in humans, with severe malarial disease almost exclusively associated with p. falciparum infection. falciparum malaria is responsible for considerable morbidity ( - million annual clinical cases) and death across the globe, with a particular burden of mortality among children in sub-saharan africa. infection with p. vivax is rarely fatal, but is associated with considerable morbidity outside the african continent. it should also be recalled that malaria causes social and economic disruption on a uniquely large scale [ ] . severe adult malaria is a clinical syndrome originally classified using defining and supportive (often overlapping) clinical features unified by the presence of asexual malarial parasites in the peripheral blood smear [ ] . based on observations of children in coastal kenya, paediatric severe malaria has similarly been distilled into three main (again often overlapping) clinical syndromes, anaemia, respiratory distress (an indicator of an underlying metabolic acidosis) and impairment of consciousness [ ] . these clinical syndromes are discussed below. in the review mentioned above [ ] , the authors' judicious use of the term impaired consciousness, rather than cerebral malaria (cm), promoted the useful concept that the neurological features (and in-turn the underlying mechanisms) associated with severe malaria are not necessarily unique to malarial disease. indeed, over years ago, it was noted that the clinical features of malaria can resemble those exhibited in patients with fulminant bacterial or viral infections [ ] . severe malaria has been intensively studied, and there appears to be a complex interplay between host infection and disease. this is highlighted by the different clinical manifestations of severe malaria exhibited by children and adults. these differences are undoubtedly, in part, a function of patient age. however, age is just one of a series of interacting factors, e.g. geographical region, level of malaria transmission, degree of previous malaria exposure, length of illness prior to treatment and host immunity that may influence the clinical presentation of severe malaria. this variation in clinical presentation has been mirrored by a similar multitude of proposals regarding the functional mechanisms underlying pathogenesis of severe malaria. one concept of pathogenesis consistently articulated has been the 'mechanical theory'. historically, this theory was developed from two fundamental differences between p. falciparum and p. vivax infection. firstly, erythrocytes parasitised with p. vivax do not sequester. secondly, death following p. vivax infection is rare. consequently, pathogenesis is believed to be due to obstruction of micro-vascular flow by erythrocytes containing mature-stage falciparum parasites adhering to the endothelium (termed sequestration). more recently the 'cytokine theory of disease' has also gained credence. this theory can be applied to disease following both falciparum and vivax infection. the lower mortality associated with p. vivax being explained by a relatively milder degree of pro-inflammatory imbalance during the host's response to p. vivax infection. the main theme of this chapter is to examine the increased understanding of the functions of inflammatory cytokines gained over the past years, and explore how these insights are changing attitudes in malarial disease research. we also discuss how two theories (mechanical and cytokine) can, as proposed first in a recognisable form at least years ago [ ] , be complementary. the majority of the clinical cases of malaria occur in sub-saharan africa. nevertheless, malaria also accounts for considerable morbidity and mortality in other continents particularly south east asia [ ] . in malaria-endemic regions (e.g. sub-saharan africa), where the resident population have continuous exposure to malarial parasites, most of the severe cases are seen in children [ ] . in hypoendemic regions (e.g. south east asia), where parasite exposure is more intermittent, cases of severe malaria are also common in adults (tab. ). clinical features associated with malaria mortality vary between children and adults, but acidosis and coma are associated with malarial mortality in both populations [ , ] . acute renal failure (arf) and pulmonary oedema, a marker for adult respiratory distress syndrome (ards), are almost exclusively reported among adults [ , ] , whereas mortality associated with hypoglycaemia is frequently reported among children [ ] . why malarial disease displays such age-related differences in pathophysiology is unclear. however, these differences are not exclusive to malaria. ards, which is more frequently observed as a complication of trauma in adults compared with children [ ] , is believed to reflect an exaggerated pro-inflammatory response within the lung [ ] . a possible lead for future studies on these age-related differences in malaria is suggested by a report of peritoneal macrophages collected from healthy adults producing much less interleukin (il)- (an anti-inflammatory cytokine), but the same levels of pro-inflammatory cytokine, than those from healthy children, giving adults a much higher pro-inflammatory status [ , ] . the mechanism of malarial arf pathogenesis is postulated to be multifactorial, involving mechanical, haemodynamic, and immunological factors [ ] . the observation that arf is more frequently observed as a complication of trauma in adults than children [ ] suggests that age-related variations in cytokine response may again influence pathogenesis. hypoglycaemia is regarded as a more frequent complication of sepsis in paediatric populations compared with adults [ ] . hypoglycaemia in children may, in part, be associated with a higher basal metabolic rate, and lower glycolytic [ ] and gluconeogenic substrate reserves compared to adults [ ] . however, these substrates are not always limiting during acute paediatric malaria, suggesting functional impairments of glucose metabolism may also occur [ ] . such functional impairments may, in part, be influenced by increases in inflammatory cytokines as the infection progresses. once the malarial parasite was identified as the cause of disease, it quickly became apparent that illness and death were linked with parasite invasion into bloodstream and subsequent parasite growth within (and release from) the erythrocytes. by the start of the th century, two major theories, capillary blockage and toxicity of the parasites themselves, had been proposed to explain morbidity and mortality. thus, the study of malarial disease is not a settled story requiring regular updates, but one containing, from its beginning, an unresolved tension. vascular occlusion and malarial toxin (nowadays vascular occlusion and inflammatory cytokines) have been alternative approaches to understanding malarial disease as a whole, as well as the coma, for over a century, and the two have often been discussed side by side [ , , ] . the presence of hyperlactataemia, hypoglycaemia, and metabolic acidosis, all three consistent with a patient being forced to rely on anaerobic glycolysis for energy production, have provided a consensus that hypoxia is central to disease pathogenesis in falciparum malaria. as sum-marised below, the modern literature offers two main theories for cellular hypoxia during infection; insufficient oxygen delivery to cells and impaired oxygen utilization within the cells. both mechanisms may be governed by the host inflammatory cytokine response to infection. this chapter focuses on how an increased understanding of the molecular functions of cytokines during disease demonstrates a closer alignment between the pathogenesis of falciparum infection and other systemic infectious diseases. one hundred and twenty years ago, golgi (of the golgi apparatus [ ] ), noted onset of malarial fever and illness at a predictable short interval after the regular shower of new parasites were released from bursting red cells. the nature of the putative toxin so released was much discussed in the first decade of the th century [ ] . it was assumed to be directly toxic, in the manner of tetanus toxin. the proposal that malarial products were not harmful in themselves, but only through causing the infected host to harm itself through generating toxic amounts of molecules (pro-inflammatory cytokines) that, in lower concentrations, inhibit growth of malarial parasites did not arise until [ ] . indeed, acceptance of the broad applicability of this concept to infectious disease in general is now sufficient for its evolution to be a subject for research [ ] . tumour necrosis factor (tnf) is regarded as a major player, malaria being the first disease in which it was proposed to cause systemic illness and pathology [ ] . multiple tnf promoter polymorphisms have since been independently associated with severe malaria across several geographical populations [ ] . a longitudinal study in burkino faso has also demonstrated several tnf promoter polymorphisms associated with the regulation of host-parasite density [ ] . the tnf concept has since begun to dominate the sepsis literature [ ] , and the virulence of different strains of influenza, a disease that is a standard clinical misdiagnosis for imported malaria, has recently been expressed in terms of their capacity to induce tnf [ ] . the critical role of tnf in both malaria and influenza pathogenesis is consistent with the clinical similarities between the diseases. indeed, tnf infusions in tumour patients produce side effects mimicking both diseases [ ] , as discussed below. although tnf is the prototype pro-inflammatory cytokine linked with severe malaria, other cytokines (and mediators) including interferon (ifn)- [ ] , its corresponding receptors ifn-receptor- [ ] and ifn-receptor- [ ] , il- [ ] , il- [ ] and il- [ ] have all be identified through genetic association analysis to be linked with their potential regulation of malarial disease severity. all the above cytokines typically act as homeostatic agents, but can cause pathology if produced excessively. when this happens they also induce a late-onset, but long-acting cytokine termed the high mobility group box (hmgb ) protein, which prolongs and amplifies inflammation [ , ] . this molecule, normally in the cellular nucleus and previously known only for several physiological functions, now shows great promise as a therapeutic target in sepsis, in that countering it after the onset of illness protects well in experimental sepsis [ , ] . it accumulates, in proportion to degree of illness, in serum from african children infected with falciparum malaria [ ] . once neutralising anti-tnf antibodies became available for human use, they were tested for efficacy against malarial disease. unfortunately, a central tenet of the cytokine concept of infectious disease (that the proinflammatory cytokines that cause disease are the same mediators that, in lower concentrations, are responsible for the innate immunity that controls parasite growth) was not taken into consideration. tnf has been shown to inhibit a mouse malarial parasite in vivo [ ] , and p. falciparum in vitro, provided white cells to generate the next down-stream mediator, possibly nitric oxide (no) [ ] , were present [ ] . this is consistent with findings in human subjects [ ] . thus, it is not surprising that anti-tnf antibody, by removing inhibitory pressure from the pathogen, can enhance the disease in falciparum malaria [ ] , as shown years earlier in human sepsis [ ] . cytokines as a disease mechanism extends beyond malaria as noted above, the idea that excessive production of inflammatory cytokines underlies the pathology of illness is used widely, from malaria across a range of conditions, infectious or otherwise. as reviewed recently [ ] , this now includes the illnesses caused by rickettsias, protozoa other than malaria, and viruses. increased circulating levels of these cytokines have been detected in the serum very soon after onset of illness in virtually all those infectious diseases in which they have been sought. some cytokine increased, and consequences are shown in table . when rtnf was under trial in volunteers as an anti-tumour agent [ , ] nearly years ago, virtually all of the symptoms and signs they share were reproduced as side effects. this includes headache, fever and rigours, nausea and vomiting, diarrhoea, anorexia, myalgia, thrombocytopaenia, immunosuppression, and central nervous system manifestations, all of which have been shown to be caused by a mechanism involving inflammatory cytokines. the rate, timing and intensity of cytokine release vary in different disease states, and provide them with somewhat individual clinical pictures, but the fundamentals remain. nevertheless, the clinical patterns generated are remarkably close, in that, at least in some populations, clinical features cannot predict a diagnosis of malaria from other causes of fever [ ] . mature erythrocytic forms of p. falciparum are not seen in peripheral blood smears, and cause the erythrocytes they inhabit to adhere to the walls of venules and capillaries. from this observation arose the widely held view that much of the pathology following malarial infection is explained through parasite sequestration causing impairment of microvascular flow. sequestration certainly occurs, since the life cycle dictates this. however, whether the temporal and anatomical patterns of sequestration are the same in both individuals with fatal disease and in parasite tolerant individuals has not been ascertained. consequently, whether sequestration is the principal instigator of local pathology, or whether sequestration is an associated feature of all malarial infections with local pathology determined by other factors in the host response to the infection, e.g. a local imbalance of inflammatory mediators, has not been fully elucidated. erythrocyte cyto-adherence (irrespective of whether this adhesive process is directly or indirectly due to parasite sequestration) has repeatedly been shown to be mediated through a series of host-derived ligands. cd and thrombospondin were the first described endothelial receptors that bound infected red blood cells (rbcs) [ , ] , with most studied wild parasite isolates demonstrating adhesion to cd [ ] . more recently, it has been shown that p. falciparum also interacts with other host adhesion receptors, i.e. intercellular adhesion molecule- (icam- cd ), vascular cell adhesion molecule- (vcam- cd ) and e-selectin [ , ] . certain adhesive phenotypes, such as rosetting (the spontaneous tethering of infected and non-infected rbcs) and clumping (tethering of infected rbcs through platelets) have been preferentially associated with severe malarial disease [ , ] . cd is involved in both mechanisms of adhesion, and a non-sense mutation in the gene encoding for cd has also been associated with protection from severe malaria [ ] . polymorphisms in the gene encoding icam- have also been associated with susceptibility to severe disease [ ] . furthermore, icam- , together with vcam and e-selectin, are up-regulated by tnf, with circulating levels of these ligands shown to be increased in severe malaria compared to uncomplicated infection [ ] . sequestration during falciparum malaria appears to be concentrated in the brain and placenta. there is some evidence to suggest that the propensity of inflammatory cytokines to up-regulate cell adhesion molecules, secondary to local variation in the density of thrombomodulin, is potentially higher in the microvasculature of the brain and placenta compared to other tissues. as reviewed [ ] , tnf and il- increase tissue factor expression on endothelial cells, thereby initiating pathways that generate thrombin [ ] . when thrombin binds to thrombomodulin on the endothelial cell surface, protein c is activated, which in turn can lead to further downstream activation of the coagulation cascade. therefore vasculature with lowest thrombomodulin densities on the endothelial cell surface (brain least, placenta next least, and other organs more [ ] ) will have more unbound thrombin available for its other functions on activated endothelium. these other functions include up-regulation of adhesion molecules such as selectins, icam- , vcam- [ ] and monocyte chemotactic protein- (mcp- ) [ ] . therefore, up-regulation of adhesion molecules within the cerebral vessels may occur as a local endothelial response to systemic inflammation and may not necessarily be precipitated by parasite sequestration. anaemia is another obvious way in which too little oxygen reaches cells, and thus their mitochondria [ ] . as recently reviewed [ ] , critical illness associated with an inflammatory response invariably causes multifactorial anaemia. obviously a high parasite load in malaria indicates that the infected rbcs will soon burst when the next generation of erythrocytic forms escapes, but anaemia does not correlate with parasitaemia, and sometimes is extreme when very few parasites are, or have been, present. the severe anaemia in transgenic mice expressing human tnf [ ] incriminates the inflammatory response itself, so anaemia and mitochondrial dysfunction (see mitochondrial dysfunction section below), both consequences of systemic inflammation, can be expected to coexist, and both contribute to total energy depletion. the lifespan of an rbc is, in part, limited by how long it can remain flexible enough to squeeze through fenestrations in specialised vessels in the red pulp of the spleen, and thus avoid phagocytosis by adjacent macrophages. normally this loss is balanced by erythropoiesis, and haematocrit remains normal. if rbcs develop a premature loss of deformability they are removed from the circulation earlier. this loss of deformability happens to both infected and non-infected red cells in malaria, whether caused by p. vivax or p. falciparum. under physiological conditions, erythrocytes (and other cells) control the passive influx of osmotic active solutes (especially na + ) via an active, energy-dependent elimination of these solutes using na + /k + -atpase. this prevents intracellular accumulation of osmotically active solutes, preventing a subsequent influx of water, cell swelling and loss of cell integrity. during human [ ] and monkey [ ] malaria infection, intracellular na + accumulates within erythrocytes (both parasitised and non-parasitised) implying that this na + /k + pump is impaired during the disease process. parallel changes in the ionic content of erythrocytes have been documented in a sepsis model of infection [ ] . similarly, reduction in erythrocyte deformability was shown to be associated with increased no, an inhibitor of this membrane pump [ ] , in another sepsis model [ ] . since inhibition of the na + /k + pump in vitro correlates with both reduced red cell deformability and decreased red cell filterability [ ] , any factor that inhibits the na + /k + pump could potentially worsen anaemia. identification of inducible no synthase (inos) activity, as one factor influencing red cell deformability, suggests that a pro-inflammatory milieu [ ] may again govern the reduction in red cell deformability observed during malaria infection. originally observed in uraemic patients, poor red cell deformability was recognised in a small pilot study of malaria patients in [ ] . it was reported soon afterwards in sepsis [ , ] , and subsequently studied in falciparum malaria with a view to understanding both circulatory obstruction [ ] and anaemia [ ] . it seems clear that a short life (poor deformability), and a slow replacement rate (dyserythropoiesis, below) can combine to cause severe anaemia in various diseases, particularly in chronic infections such as malaria. when red cells have a shortened lifespan, e.g. secondary to reduced erythrocyte deformability, replacement by new recruits is vital to avoid anaemia. unfortunately, the same inflammatory cytokines that shorten lifespan also retard replacement. some years ago researchers began to stress the contribution of bone marrow dyserythropoiesis to the anaemia of falciparum malaria [ , ] . a group in oxford [ ] , seeking an explanation for this dyserythropoiesis through an electron microscopy study of bone marrow, observed sequestration of parasitised red cells and argued that this caused the bone marrow dysfunction in falciparum malaria by restricting blood flow and thus inducing hypoxic changes. this idea proved inadequate, however, when this same group subsequently reported dyserythropoiesis and erythrophagocytosis in vivax malaria, in which parasitised red cells do not sequester [ ] . some time ago an undefined product in macrophage supernatants [ ] , later identified as tnf [ ] , was found to inhibit the growth and differentiation of erythroid progenitor cells. when rtnf became available, the dyserythropoiesis and erythrophagocytosis seen in terminal plasmodium vinckei-infected mice was reproduced by giving a single injection early in the course of the infection [ ] . phagocytosis of erythroblasts in bone marrow, a phenomenon also reported by wickramasinghe et al [ , ] in human malaria, also occurred. decreased erythropoiesis was subsequently reported in mice receiving continuous tnf infusions via implanted osmotic pumps, and mice expressing high levels of human tnf have been shown to become markedly anaemic during malaria infections [ ] , even though parasite numbers, and therefore red cell loss post-schizogony, are considerably reduced. the past decade has seen an expansion of this line of enquiry into human malaria, and also the number of cytokines, both pro-inflammatory and anti-inflammatory [ , ] in absolute amounts and ratios [ , ] , that have been investigated in this context. investigations have been extended to include other pro-inflammatory cytokines, such as il- [ ] and fasl [ ] , and examined the role in anaemia of the persistence of cytokine production during malaria infection [ ] . another inflammatory cytokine, macrophage inhibitory factor (mif) that is increased in malaria, and induced by tnf, has been shown to cause dyserythropoiesis in in vitro studies on bone marrow cells [ , ] . thus, inflammatory cytokines generated during malaria are a major determinant of the degree to which anaemia influences the amount of oxygen that reaches tissues in malaria. mitochondria are vital to energy (atp) generation through cellular respiration. cellular respiration requires oxygen and pyruvate, as well as multiple cofactors and active transport molecules. within the matrix of the mitochondrion organelle, pyruvate is catabolised via the krebs cycle and oxidative phosphorylation (involving nadh and fadh ) to generate atp. when this series of reactions are % efficient (unlikely in vivo), molecule of glucose generates molecules of pyruvate, which are further catabolised to water and carbon dioxide with the concomitant generation of molecules of atp. in comparison, during anaerobic glucose catabolism, pyruvate is converted to lactate with the concomitant generation of molecules of atp, a process that also facilitates regeneration of nadh and fadh . evidence is accumulating that inflammatory cytokines, as released in malaria, sepsis, and viral diseases, induce mitochondrial dysfunction and dysregulate cellular respiration, resulting in the incomplete catabolism of pyruvate. the process, termed 'cytopathic hypoxia' [ ] , mimics cellular hypoxia, in that it results in the incomplete catabolism of pyruvate and accumulation of lactate. awareness of this mechanism began with oxygen tension being shown to be increased in septic rats [ ] and patients [ ] . a cytokine model of mitochondrial dysfunction has since been developed in which impairment of cellular respiration occurs following induction of sepsis (or exposure to pro-inflammatory cytokines), despite sufficient oxygen supply [ , , ] . more recently, impairment of enzyme activity associated with the mitochondrial complexes has been demonstrated in muscle biopsies retrieved from rodent models of sepsis [ ] and septic patients [ , ] . the observation that the inflammatory cytokines implicated in mitochondrial shutdown are prominent in both sepsis and malaria [ , ] supports such organelle dysfunction being equally plausible in malaria. researchers are also becoming aware that, beyond energy production, mitochondria also play a vital role in cell homeostasis through generation and detoxification of reactive oxygen species [ ] . the accelerated oxidative damage that accompanies sepsis could be both a cause and a consequence of cytokine-induced mitochondrial dysfunction. interestingly, the ultrastructural damage reported to accompany mitochondrial dysfunction in sepsis [ ] reflects maegraith's observations in monkey malaria [ ] [ ] [ ] decades ago. metabolic acidosis, often associated with hyperlactataemia, has been described in african children with severe falciparum malaria [ , ] . it is not unique to this disease, being seen in viral, rickettsial and bacterial infections [ ] as well as acute gastroenteritis, where its prevalence is higher than in malaria [ ] . the terms hyperlactataemia and lactic acidosis are often mistakenly used interchangeably in the malaria literature. as often reviewed in the basic literature [ ] [ ] [ ] [ ] , protons (h + , the basis of acidosis) are not formed when atp and lactate are generated during glycolysis, but on the subsequent hydrolysis of atp in tissues. every time a molecule of atp undergoes hydrolysis, a proton is released. if this occurs under aero-bic conditions, these protons are consumed within atp regeneration from adp, and ph remains normal, i.e. acidosis does not occur. in contrast, if the mitochondria are not functioning adequately, whether through insufficient oxygen supply or an inability to use it, atp regenerates under anaerobic condition, and the protons are not consumed. hence, once the buffering capacity of the body is exceeded, acidosis occurs. in short, metabolic acidosis requires the ratio of glycolytic (i.e. anaerobic) atp hydrolysis to mitochondrial (i.e. aerobic) atp hydrolysis to reach a point at which the buffering systems can no longer cope. pathological changes in the buffering system can be a major determinant of when this occurs. high lactate levels have traditionally been seen not only as a marker for poor oxygen delivery in disease states, but also a consequence of it, and the cause of the acidosis. for some time hyperlactataemia has been regarded as a functionally relevant marker for a poor prognosis in both sepsis [ ] and malaria [ , , ] . although the sepsis world now discusses several origins for the lactate increase, including inflammation-induced mitochondrial dysfunction [ ] , in falciparum malaria it is still generally attributed to a reduced oxygen supply, mostly through microvascular occlusion by sequestered parasitised erythrocytes [ ] . other mechanisms are known to contribute to acidosis in malaria, independent of lactate production, e.g. acute renal failure [ ] . impaired hepatic clearance [ , ] , production by parasites, and, in some areas, thiamine deficiency [ ] are also argued to contribute to lactate accumulation independent of impaired cellular respiration. thus, as described below, although acidosis and hyperlactataemia can be associated, they are independent cellular mechanisms. lactate anion has complex roles in biology. hyperlactataemia may be associated with acidosis, a normal ph, or alkalosis [ ] . a recent editorial in critical care medicine [ ] has lucidly summarised the key points of the mechanism of metabolic acidosis in sepsis, a condition that shares systemic inflammation and a range of its consequences with severe malaria (tab. ). these authors argue against lactate as the cause of the acidosis associated with hypoxia. instead, they note the evidence that during hypoxia, be it from limited oxygen supply or utilisation, the unconsumed protons that cause acidosis arise from the hydrolysis of non-mitochondrial atp. since these reactions are independent of lactate levels, it is difficult to see how therapeutically reducing levels of this anion, as has been proposed [ ] , could increase survival rate in falciparum malaria any more than in sepsis [ ] . indeed, in theory it could harm comatose patients, since there is evidence that lactate helps brain tissue survive hypoxic and hypoglycaemic episodes [ ] [ ] [ ] , and the lactate shuttle is proving to be how astrocytes protect neurons from metabolic stress [ ] . even when considerable lactate is generated in acute inflammatory states, other, unidentified, anions contribute much more than it does to the strong ion difference that, through influencing the body's buffering capacity, influences acidosis in sepsis [ , ] and falciparum malaria [ , ] . thus, lactate accumulation can only partially account for the high anion gap observed during the metabolic acidosis associated with severe malaria. in summary, lactate is an imprecise but useful marker for metabolic acidosis in malaria. in turn, acidosis is an imprecise but useful marker of impaired cellular respiration. whether impaired cellular respiration arises from (a) poor supply of oxygen to mitochondria (through vaso-occlusion, low circulating volume, anaemia or cardiac insufficiency) or impaired mitochondrial function (in response to severe systemic inflammation) the outcome is essentially the same. the resulting high anion gap metabolic acidosis is strongly predictive of death in severe malaria. greater understanding of the multiple factors influencing the metabolic acidosis could provide further insight into the underlying pathophysiological process and may provide additional therapeutic options. when glycolysis is enhanced for any period glycogen stores are soon depleted, and gluconeogenesis supervenes. however, its substrate supplies are limiting [ ] , and the hypoglycaemia often reported in severe malaria [ ] and sepsis [ , ] occurs. hypoglycaemia is therefore a secondary cause of harm in these diseases, and is an inevitable consequence of exuberant, mostly anaerobic, glycolysis. cm is a clinical syndrome characterised by coma (inability to localise a painful stimulus) at least h after termination of a seizure or correction of hypoglycaemia, detection of asexual forms of p. falciparum malarial parasites on peripheral blood smears, and exclusion of other causes of encephalopathy [ ] . a relatively consistent feature of acute cm in children is raised intracranial pressure (icp). studies in african children have demonstrated a raised cerebrospinal fluid (csf) opening pressure during lumbar puncture in % of cm children [ ] , raised icp during intracranial pressure monitoring ( / icp > mmhg) [ ] and papilloedema (a late sign of raised icp) in % of cm patients who died [ ] . where computer tomography has been performed, there was evidence of diffuse brain swelling in % of patients [ ] . the cause of the raised icp is likely to be multi-factorial and has been postulated to involve both vasogenic and cytotoxic patterns of cerebral oedema. vasogenic oedema is characterised by accumulation of interstitial fluid within the brain secondary to increased permeability of the blood-brain barrier (bbb). it has been demonstrated in bacterial cerebral infections, but evidence of significant disruption of the bbb is not conclusive in cm [ ] . others have proposed that icam- binding by infected erythrocytes may generate a cascade of intracellular signalling events that disrupt the cytoskeletal-cell junction structure and cause focal disruption to the bbb [ ] . adult post-mortem analysis has shown cerebrovascular endothelial cell activation (increased icam- endothelial staining, reduction in cell junction staining, and disruption of junction proteins), particularly in vessels containing infected erythrocytes [ ] . however, disruption of intercellular junctions is not associated with significant leakage of plasma proteins (fibrinogen, igg, or c b- ) into perivascular areas or csf [ ] . in thai adults, transfer of radioactively labelled albumin into csf was not raised during unconsciousness compared with convalescence [ ] . similarly, the albumin index (ratio of concentrations of albumin in csf to those in blood) was not altered significantly in vietnamese adults [ ] or significantly different between malawian children with cm who died and those who survived [ ] . cytotoxic oedema is increasingly being recognised as an important mechanism of cerebral oedema in traumatic brain injury [ ] . as previously discussed, this type of cell swelling involves disturbance of the "pumpleak equilibrium" maintained, under physiological conditions via active elimination of osmotically active solutes through the energy-dependent na + /k + -atpase. thus, cytotoxic oedema can occur secondary to an imbalance in supply and demand of energy within the cells. several mechanisms, such as sustained increase in neuronal activation, impaired substrate delivery (structural and functional) and impaired mitochondrial utilisation of available substrates, including oxygen, may coexist to generate this imbalance. all these mechanisms could contribute to atp depletion and na + /k + atpase failure, leading to cytotoxic oedema in cm. cm is clearly associated with increased neuronal activity. a recent review identified that % of african children with cm have a history of seizures, with prolonged and recurrent seizures associated with a poor outcome [ ] . impaired vascular flow during acute cm may limit substrate delivery within the brain and contribute to energy imbalance. in the past, a common premise was that parasite sequestration precipitated cerebral vaso-occlusive/ischaemic (i.e. stroke-like) events that manifested clinically as cm. however, cm demonstrates several features that are atypical for stroke. in children, focal neurological signs do not tend to accompany coma, although a sub-set of patients do exhibit hemiparesis or focal brainstem deficits during the agonal period [ ] . the incidence of residual neurological deficits following recovery from coma is relatively low ( % [ ] ) when compared to childhood stroke ( % had residual neurological deficit [ ] ). where computer tomography has been performed in children, diffuse brain swelling was observed [ ] rather than focal lesions more typical of stroke. although retinal haemorrhages have been observed in % of malawian children with cm (and in % of patients who died), these lesions were also seen in % of children with sma in the same study [ ] . consequently, although associated with cm, retinal haemorrhages do not confirm that focal cerebral vaso-occlusive/ischaemic events underlie cm. similarly, histological examination of fatal cm cases of african children at autopsy demonstrated that one third had little or no evidence of local vascular change in the brain, as indicated by sequestered parasites, monocyte clusters, micro-haemorrhages, local vascular inos [ ] or haemoxygenase - (ho- ) [ ] staining. accepting that cm may occur without ischaemia does not exclude temporary or less severe reductions in vessel flow occurring during acute cm (associated or independent of parasite sequestration) that may contribute to impaired substrate delivery and lead to energy imbalance. as previously discussed, energy imbalance may also be impaired due to the uncoupling action of inflammatory cytokines on mitochondrial atp production. in gambian and ghanaian children, concentrations of tnf and its receptor were higher in those with cm than in those with mild or uncomplicated malaria [ , ] . polymorphisms in the tnf promoter region have also been associated with increased risk of cm and death [ ] or neurological sequelae [ ] . cytokines may also up-regulate inos in brain endothelial cells, increasing production of no, which could then diffuse into brain tissue and disrupt neuronal (and/or mitochondrial) function [ , ] . in the brain, mitochondrial function may also be influenced by neuronal excitotoxins. within the simplified model of dissociated neuronal culture, mitochondria appear to play a critical role in neuronal homeostasis during excitotoxin exposure. mitochondria are not only involved with maintaining atp production but also calcium homeostasis, and generation and detoxification of reactive oxygen species [ ] . excitotoxin production may also be influenced by cytokine release. tnf administration has been shown to alter brain metabolism of tryptophan to produce more kynurinine [ , ] . thus, as part of a general inflammatory reaction, increased excitotoxin generation during acute malaria may contribute to cellular energy imbalance. elevated levels of neuronal excitotoxins (quinolinic and picolinic acid) in the csf have been associated with a fatal outcome in malawian children with cm [ ] . similarly, a graded increment of quinolinic acid concentration in csf was observed across patient outcome groups of increasing severity in african children [ ] . although a subset of the malawaian autopsy patients [ ] demonstrated negligible histological change in their brains, they did demonstrate inflammation, as indicated by inos, mif [ ] and ho- [ ] , staining in other tissues. these systemic changes were shared with the comatose sepsis cases in the study, and therefore are consistent with the premise that coma may in part be secondary to a host inflammatory response to systemic infection. below are further examples of systemic responses to infection that present with diffuse cerebral syndromes, including coma. in the past, the term cm has been restricted to falciparum malaria, and patients with p. vivax infection exhibiting symptoms of severe malaria, including coma, have been dismissed as undiagnosed falciparum co-infections. however, the use of more sensitive diagnostic techniques makes such dismissal less tenable. two such studies report adults exhibiting severe malaria with p. vivax (but not p. falciparum) infection detectable on pcr and serological and testing [ , ] . the patients exhibited multiple organ failure including cerebral symptoms, renal failure, circulatory collapse, severe anaemia, haemoglobinuria, abnormal bleeding, acute respiratory distress syndrome, and jaundice. vivax malaria has been associated with a strong systemic inflammatory response [ ] , but this was not investigated in the above studies. sepsis-associated encephalopathy (sae) syndrome has multiple features that resemble cm. it is characterised by a diffuse disturbance of cerebral function (typically impairment of consciousness) that occurs in the context of systemic response to infection without direct neuroinvasion (i.e. meningitis, macroscopic cerebritis and brain abscesses are excluded). sae is associated with generalised slow waves on the electroencephalogram (eeg), with the depth of coma linked with mortality. mild sae cases often recover completely, while survivors of severe sae may have persistent neurological deficit [ ] ). in line with adult cm, the severity of encephalopathy parallels the severity of systemic organ failure [ ] . inflammatory cytokines have been demonstrated to be higher in the serum than in the csf, suggesting that sepsis encephalopathy is a consequence of the systemic inflammatory response to infection [ ] . an animal model in which prior administration of a neutralising antibody to tnf prevented the sepsis encephalopathy of pancreatitis [ ] is consistent with this. further postulated reversible mechanisms of pathogenesis include changes in regional cerebral blood flow, neurotransmitter imbalance, mitochondrial dysfunction, bbb impairment and oxidative stress [ ] . severe influenza infection can present with encephalopathy, yet as in malaria, the pathogen is not neuroinvasive [ ] . seizures and coma occur after high fever [ ] , commonly accompanied by thrombocytopaenia [ ] , with metabolic acidosis and hyperlactataemia in severe cases (t. ichiyama, personal communication). similar to adult malaria, neurological sequelae occur concurrently with multiple organ failure [ ] . tnf, il- , stnfri, and soluble e-selectin are increased in serum and csf [ , ] , and serum nitrite/nitrate levels are increased [ ] . detailed examination of brain has revealed apoptosis of neurons and glial cell, histological evidence of active caspase- and caspase-cleaved parp, cerebral oedema, and bbb impairment [ ] . these parallel changes are set out in table . it is clear, therefore, that the presence of sequestering parasitised red cells is not necessary to generate these changes, which are also demonstrable in the falciparum malaria encephalopathy. notably, high levels of inflammatory cytokine are present in each disease. seizures are a very common component of acute malaria illness in children. a recent review documented that % of african children had a history of seizures, with % exhibiting seizures during hospital admission [ ] . the molecular basis of the seizures is unclear. multiple mechanisms have been postulated, including fever, hypoxia and/or cytokine stimulation leading to an imbalance of neurotransmitters and excitotoxins or neuronal damage [ , ] . recently, lang and co-workers [ ] demonstrated that falciparum parasitaemia is associated with the generation of specific antibodies for voltage-gated calcium channels directed against neurones. higher antibody concentrations were detectable in sera from patients exhibiting cm or malaria with seizures than uncomplicated malaria, suggesting that these antibodies may influence seizure propensity. only the erythrocytic form of malaria is associated with disease, so valuable information about which african children are likely to have more, or less, severe malaria has inevitably been obtained from examining the inborn rbc abnormalities that endemic malaria has selected across the tropics. the coinciding geographic distributions of malaria transmission and the thalassaemias prompted haldane to put forward the 'malaria hypothesis', which proposed that common erythrocyte abnormalities are selected because of the fitness advantage they confer against malaria [ ] . sickle cell haemoglobin (hbs) has also been repeatedly shown to be associated with malaria resistance, with heterozygotes for the hbs trait demonstrating % of the population at risk for severe malaria in certain populations [ ] . other haemoglobinopathies (e.g. hbc [ , ] and hbe [ ] ) and deficiencies in rbc enzymes (e.g. glucose- -phosphate dehydrogenase deficiency [ ] ) have also been linked with protection against severe malaria. the mechanisms of protection afforded by haemoglobinopathies are likely to be multi-factorial. studies have demonstrated evidence to support several independent mechanisms including: reduced parasite invasion of rbcs and diminished intraerythrocytic growth of parasites in patients with the hbs trait [ ] , enhanced phagocytosis of parasite-infected erythrocytes (ies) [ ] and enhanced immune responses against ies [ ] . recent in vitro studies observed that hbc modifies the quantity and distribution of the variant antigen p. falciparum erythrocyte membrane protein (pfemp ) on the ie surface. pfemp has been implicated in numerous ie adhesive interactions. in the latter study the authors demonstrated that hbc reduces the level of ie adhesion to endothelial monolayers, in addition to ie rosetting (the adhesion of ies to uninfected erythrocytes) and ie agglutination by sera. these findings provide the prospect that hbc pro-tects against severe malaria by mitigating the obstruction and inflammation caused by the pfemp -mediated adherence of ies [ ] . however, sequestration is believed to enhance parasite survival by enabling ies to avoid splenic clearance, so any reduction of sequestration by hbc can be expected to limit parasite fitness. multiple epidemiology studies (e.g. [ , , ] ) have failed to identify any significant impact of hbc on the frequency or density of parasitaemia in naturally exposed populations. consequently, the influence of the changes in ie surface conformation needs to be confirmed and further examined in vivo [ ] . a recent study re-confirmed that african children with -thalassaemia trait are significantly less likely to be hospitalised with severe malaria, particularly with coma or severe anaemia (hb < g/ ml). it is intriguing that the -thalassaemia patients did not demonstrate a lower incidence of uncomplicated malaria nor any reduction in peripheral parasite density [ ] . thalassaemia has also been associated with increased incidence of clinical vivax and falciparum malaria during early life [ ] . the findings raise speculation that the trait may indirectly afford enhanced immunity through increased non-lethal exposure to malarial parasites. such a mechanism is appealing, since it would be equally plausible across a range of haemoglobinopathies, including hbc. variations in erythrocyte membrane proteins also have a profound influence on malaria susceptibility. most notably the absence of duffy antigen protein confers absolute protection to p. vivax infection. more recently, the duffy antigen has also been associated with a protection against falciparum malaria [ ] . enzymes involved with iron handling may also have a critical influence on malaria morbidity. a recent study from the gambia demonstrated that children in an endemic malaria area possessing the haptoglobin , , isotype had a significantly increased risk of anaemia [ ] . however, a lack of parallel alterations in other haematinic indices leaves the mechanism of this process unclear. malarial protection within individuals exhibiting multiple rbc abnormalities appears even more complex. a recent study observed that the concurrent presence of sickle cell and -thalassaemia trait among african children had a negative influence on the risk of malaria infection [ ] . the results warn geneticists that gene epistasis may have a profound influence on overall malarial susceptibility. in tropical countries many hospital deaths from falciparum malaria happen before anti-malarial drugs have had time to kill the parasites. two approaches could help rectify this -addressing public-health problems resulting in delayed presentation, and identifying the physiological processes and molecular pathways that lead to these early deaths, with a view to developing evidence-based adjunct therapies. therapies being explored in sepsis, and based on disease pathogenesis data common to sepsis and malaria, may prove to be transferable from either of these diseases to the other. as noted above, circulating levels of a late-appearing inflammatory cytokine, hmgb , are increased in falciparum malaria [ ] as well as in sepsis. results from animal models on the role of hmgb , although untested in humans, have inspired enthusiasm for inhibition of this molecule as a potential intervention for human sepsis. for instance, anti-hmgb antibodies provided dose-dependent protection [ ] and reduced mortality [ ] against experimental sepsis in mice. late administration of ethyl pyruvate, which inhibits hmgb release from macrophages, also conferred protection against endotoxaemia in mice [ ] . treatments directed towards critical downstream consequences of malaria infection and inflammation, such as those intended to limit acidosis, are also a focus of investigation. one current approach is to identify which acute malaria patients most benefit from early volume expansion [ ] . controlling lactic acidosis via sodium dichloroacetate (dca), an inhibitor of pyruvate dehydrogenate kinase (maintaining pyruvate dehydrogenase in its active form), is also being examined. dca reduced lactate levels in acute malaria patients [ ] , although the study was unable to determine whether treatment improved outcome. an earlier large sepsis study also demonstrated that dca reduced lactate, but again with no improvement in outcome [ ] . as outlined in the section 'is hyperlactataemia a cause or marker of the acidosis of malaria?', some researchers argue, in view of the strong ion difference contributing to acidosis and the postulated mitochondrial dysfunction during acute malaria infection, that lactate reduction per se may have limited impact on prognosis. other adjunct therapies are also being examined. improving rbc deformability provides one potential therapeutic approach. in vitro studies with n-acetylcysteine (nac), reported to scavenge free radicals, showed improvement in red cell deformability through in vitro studies [ ] . unfortunately, an initial in vivo trial of nac in malaria patients had no effect on mortality [ ] . blocking endothelial activation is also a focus of research, with initial in vitro studies providing some encouraging results [ ] . in conclusion, continuing to identify the host responses to malaria infection that lead to disease is providing insights into novel molecular mechanisms. this information is 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expansion with albumin or saline in children with severe malaria: preliminary evidence of albumin benefit pharmacokinetics and pharmacodynamics of dichloroacetate in children with lactic acidosis due to severe malaria oxidative stress and rheology in severe malaria a pilot study of n-acetylcysteine as adjunctive therapy for severe malaria inhibition of endothelial activation: a new way to treat cerebral malaria key: cord- - n hml authors: brown, colin s.; garde, diana; headrick, emily; fitzgerald, felicity; hall, andy; harrison, hooi-ling; walker, naomi f. title: ebola virus disease in the obstetric population date: - - journal: ebola virus disease doi: . / - - - - _ sha: doc_id: cord_uid: n hml the clinical management of ebola created a significant challenge during the outbreak in west africa, due to the paucity of previous research conducted into the optimum treatment regimen. that left many centres, to some extent, having to ‘work out’ best practice as they went along, and attempting to conduct real time prospective research. médecins sans frontières (msf) [ ] were the only organization to have provided relatively in depth practical guidance prior to the outbreak and this manual was the basis of further planning between the who, national ministry of health and sanitation in sierra leone, and other relevant stakeholders. additionally, guidance changed over the epidemic as experience grew. this chapter will describe four key areas in the management of ebola in west africa. firstly, it outlines the most recent who guidance; secondly, it looks back at how ebola was managed in differing low and high resource settings; thirdly it outlines possible and optimal options for managing complications, paying particular attention to some of the controversies faced; fourthly it describes recent and ongoing studies into potential novel therapies that may shape future practice. the clinical management of ebola created a significant challenge during the outbreak in west africa in / , due to the paucity of previous research conducted into the optimum treatment regimen. that left many centres, to some extent, having to 'work out' best practice as they went along, and attempting to conduct real time prospective research. médecins sans frontières (msf) [ ] were the only organization to have provided relatively in depth practical guidance prior to the outbreak and this manual was the basis of further planning between the who, national ministry of health and sanitation in sierra leone, and other relevant stakeholders. additionally, guidance changed over the epidemic as experience grew. this chapter will describe four key areas in the management of ebola in west africa. firstly, it outlines the most recent who guidance; secondly, it looks back at how ebola was managed in differing low and high resource settings; thirdly it outlines possible and optimal options for managing complications, paying particular attention to some of the controversies faced; fourthly it describes recent and ongoing studies into potential novel therapies that may shape future practice. there is, as yet, no specific cure for evd and the mainstay of treatment is supportive care and managing complications, alongside ring-fence vaccination of close contacts. however, due to many tropical illnesses masquerading as ebola, and thus requiring isolation and evd testing, it is worth bearing these diagnoses in mind as empirical treatment for them should be considered in the undifferentiated patient (table . ). this is particularly important in contexts lacking diagnostic resources, and additionally, with the current absence of a rapid diagnostic test that has been widely used or field tested. as an example, o'shea et al. [ ] reviewed patients who presented with suspected evd but tested negative, at the uk ministry of defense etu at kerrytown, sierra leone. eleven had malaria ( . %), shigella spp. or e. coli, a respiratory infection and , an undifferentiated febrile illness supporting the need for empirical malaria and antibiotic treatment. the who released their most recent guidance on the management of ebola in february . this is recognised as the gold standard in the low-income setting, however, it is possible that the capabilities of many centres will not meet these targets. the who classifies the patient into three categories of severity; mild, moderate and severe. these are briefly summarised here, but for specific guidance the most up to date version of the who manual should be referred to. the patient will be haemodynamically normal, able to eat and drink, have no complications nor evidence of dehydration. empirical oral broad-spectrum antibiotics, anti-malarials and oral rehydration solution are recommended. treatment for symptoms such as pain, fever and dyspepsia can be provided orally. patients often have vomiting and diarrhoea, are weak and look dehydrated with sunken eyes and a skin pinch slow to return. antibiotics and anti-malarials should ideally be given intravenously, however, if there are contraindications to intravenous line insertion, can be administered intramuscularly. fluids should be given intravenously with additional oral rehydration solution. severe this patient will be severely dehydrated and shocked from either dehydration, sepsis or bleeding, although haemorrhage in the west african outbreak was seen in as little as - % of cases. empirical broad-spectrum antibiotics should be administered intravenously within the first hour of presentation, along with anti-malarials, and effective intravenous fluid resuscitation is essential. tables are provided in the who guidelines to calculate fluid requirements, however, as a rule of thumb an adult who is severely dehydrated or shocked would be treated with a bolus of l in the first min. monitoring the patient for acute fluid overload with regular vital sign measurement and fluid balance charts is required. in ill patients, the who advocates testing for malaria and hiv, and measuring potassium, sodium, bicarbonate, blood glucose, creatinine, and lactate. for women of a childbearing age, a pregnancy test should be performed as a priority. if possible, magnesium, haemoglobin or hematocrit, platelet count, inr and aptt should also be tested. in all instances management of symptoms and signs is required-these are described in the management of complications section below. there was great variation in evd management in practice, influenced in part by resource discrepancies, differences in case load and staffing, and disagreements in best practice that developed due to the void of evidence. here we discuss some of the different evd management settings, the type of care that was provided and the impact that these differences may have had on patients' outcomes. table . describes the variation in care across the three most affected west african countries at low and high resource centres, and those repatriated or treated within europe and the united states. there was a wide variation in reported mortality rates. however, the heterogeneity of populations studied, demographics, geography, time period (early versus late in the outbreak), survivor bias (only trans cut pacing- , none cpr uyeki et al. [ ] patients who made it as far as hospital settings were included) most likely explain most of this variation, rather than the effect of differing management strategies. therefore, drawing a meaningful conclusion from these mortality trends about the effect of treatment strategies is very difficult, though expanded access to staffing, therapeutic monitoring, blood product support, and critical care is almost certainly contributory to improved survival. there was a range of the care delivered from differing facilities across the world. as aforementioned, the most recent who manual outlines categorizing the patients into mild, moderate and severe, however, this was not available at the start of the outbreak and many centres used their clinical judgment to determine appropriate therapy. additionally, there was variation across laboratory testing, diagnostic abilities, clinical management and discharge criteria. this was due to multiple factors including the human resource and funding allocation, geography of the unit and specific patient factors (such as time of day they presented and agitation levels) which affected the safety of procedures. a key component to the mohs operational plan for country preparedness was the establishment of isolation facilities at every hospital admitting suspected, rather than just confirmed cases. ehu's such as at connaught hospital in freetown provided a point of access to basic health care where unfortunately in practice the highest levels of management generally only reached intravenous lines and iv fluid and antibiotic therapy, due to resource constraints, leaving laboratory testing and closer monitoring to the etcs. isolation in these facilities was expected to be for less than h, while waiting for blood results and transfer, however, patients were often waiting much longer due to delay in diagnostics and limited bed availability and thus received basic care for this period of time. additionally, at the height of the outbreak when the number of suspected cases exceeded bed availability, there were many patients who were forced to wait outside hospitals, etcs or at home, receiving only ors, until a beds became available. it is clear now that this time window was critical for patient resuscitation and the ability to check laboratory results and correct electrolyte imbalances would have been of significant benefit. even once a patient reached an etc, the level of care differed widely. for example kenema etc, in the east of sierra leone, one of the first etcs set up by msf and a h drive away from the ehus in freetown was able to perform basic laboratory tests but often was so overburdened with cases that optimal management was challenging. however, in kerrytown, sierra leone, where the british funded two etc sites, one staffed by save the children and the other through the ministry of defense, patients could receive a higher level of care from onsite laboratory services measuring and correcting electrolyte imbalances and a lower patient to staff ratio allowing more time and a safer environment for monitoring and delivering intravenous fluid resuscitation. unfortunately, epitomizing the global delay in rapid response to the outbreak, kerrytown opened in late november providing a mere two months of care during the height of the outbreak. in addition, the uk mod etc at kerrytown limited its patients through selecting only health care workers who had become infected, and with a high level of resources were able to do all supportive interventions apart from intubation and ventilation and renal replacement therapy. from the review conducted by ukeyi et al. [ ] on the care of patients with ebola in the us and europe, it is clear that in all centres regular monitoring and laboratory testing were available and management was tailored to results. five patients received renal replacement therapy, nine received non-invasive and invasive ventilation and transcutaneous pacing was conducted on one patient. none of the patients in any of the settings received cardiopulmonary resuscitation as it was deemed that once a patient had lost cardiac output, resuscitation would be futile. complications (table . ) at the start of the outbreak there was reluctance to provide intravenous fluid therapy mainly due to the risk to health care workers and challenges surrounding observing patients for bleeding complications, and therefore oral rehydration solutions were relied upon. however, over the course of the outbreak there developed an understanding of the mechanisms of death from ebola through shock, with high lactate (values reported as ranging from to mm/l [ ] ), hypoxia from late multi-organ failure, renal failure and electrolye imbalances, in particular hypokalaemia from diarrhoea. this led to a consensus that the basic principles of resuscitative supportive care should be applied with aggressive management of intravascular volume depletion, the correction of electrolytes and prevention of complications associated with shock (hunt et al). in one well-documented case managed in a german intensive care setting, diarrhoeal output exceeding l in h was reported, with intravascular collapse, and was managed aggressively with fluid repletion ( - l per day). intravascular leak did occur (pleural effusions, pericardial effusion, ascites) but overall, the treatment was successful [ ] . certainly dallatomasinas et al. [ ] noted that % of deaths occurred within days of admission, when supportive therapy is most likely to impact survival. there still is, however, uncertainty on how much, what type and how fast, fluid should be given promoting suggestions that further research is required in these areas, to optimize simple interventions, including resuscitation with a pre-mixed ebola specific fluid [ ] . there were very few complications related to fluid overload in the west african setting, and perner et al. [ ] commented on minimal capillary leak and less hypoxaemia/ards than in western sepsis, suggesting that perhaps not enough fluids were given as opposed to too much. unfortunately, the challenges faced from high patient to staff ratios, limited time inside the unit and concerns over bleeding risks through iv cannulation, (although clinically significant gastrointestinal bleeding was reported in less than % [ ] ) meant that patients were likely not receiving optimal medication. electrolyte disturbances are common in evd, although electrolyte monitoring was not widely available in west african holding units and treatment centres. case [ ] . hyperkalaemia was associated with acute kidney injury and mortality. in the same series, hyponatraemia was also prevalent, in over % patients. [ ] . the uk's ebola referral hospital, the royal free, is now prepared to perform haemodialysis and intubation. there are still no standardised guidelines for use in high income settings, however, the current recommendations are that organ support should be available but that interventions should be limited with a do not resuscitate (dnr) order place. there are no specific treatments with proven efficacy for ebola. the rapid and unpredictable onset of evd outbreaks, together with their often remote location and hazards to health workers prove a major challenge to therapeutic trial implementation. a series of eight symptomatic patients in kikwit, in , given convalescent whole blood, was the largest reported attempt at a an ebola therapeutic intervention study, prior to the west african ebola outbreak [ ] . however, this has been a rapidly evolving field. the scale and duration of the west african evd outbreak, involving patients in urban and high resource settings, provided the opportunity and incentive for accelerated research into therapies and clinical trials. efficacy studies to date have consisted of: . in vitro and animal studies . case reports/small case series of occasional or "compassionate" human use . phase ii clinical trials interventions have been either post-exposure prophylaxis (pep) in asymptomatic exposed individuals, and/or treatment in symptomatic cases. candidate drugs that have made it into human clinical use currently fall into four categories: . novel specific antiviral agents e.g. small interfering rnas . repurposed anti-infective agents, e.g. favipiravir . other repurposed agents e.g. amiodarone . specific immune therapies, e.g. convalescent plasma, convalescent whole blood, monoclonal antibodies such as zmapp in summary, an impressive effort to generate human trial data on therapeutic inventions, the results of which are summarized in table . (taken from brown [ ] ) has to date identified no clearly efficacious agent. there was a reluctance to attempt double-blind, placebo-controlled trials, for questionable ethical and logistical reasons (see lanini [ ] -this includes a good review of clinical trials and a discussion of the ethical issues). an opportunity to collect data on the efficacy of supportive interventions e.g. threshold for iv fluids, loperamide for diarrhea, was largely missed due to inadequate human resources, and no systematic controlled studies of such were performed to our knowledge. as evd is most likely to affect the low income setting in future, further research into interventions, such as the safety of intravenous lines, usual care versus laboratoryguided care, effectiveness of anti-diarrhoeals, empirical antibiotics and oral potassium supplements would be beneficial. provisional plans for trials should be agreed prior to the next outbreak, to improve rapid implementation when the need arises. this is a moving field and more trial data is likely to be available in the upcoming years. we suggest consulting the following useful resources for up-to-date information: https://ebolaclinicaltrials.tghn.org http://www.ukcds.org.uk/resources/ebola-research-database http://www.who.int/medicines/ebola-treatment/emp_ebola_therapies/en/ https://clinicaltrials.gov small interfering rnas, have shown potential in treatment and prevention, in non-human primates and humans. tkm- (by tekmira), was fast-tracked due to encouraging animal and phase data for a clinical study in sierra leone. however, the trial was terminated early, as demonstration of efficacy was deemed unlikely, and the product discontinued by the manufacturer [ ] . other sirna molecules are in development with encouraging data efficacy in non-human primates (limiting symptoms, abrogating mortality-siebola- , see thi [ ] ). brincidovir, a small molecule nucleotide analogue, orally available lipid conjugate of cidofovir (chimerix, inc.), was used occasionally in repatriated patients and in an open-label, single arm phase ii clinical trial (in liberia) which stopped early, favapiravir (toyama, japan), is a broad spectrum anti-viral, approved for treatment of influenza, in japan. a therapeutic effect was reported in ebola virus-infected mice and supported by relatively good outcomes in some cases of occasional human use in repatriated patients (pep and treatment). since then two historically-controlled, open-label, single arm phase ii clinical trials have been undertaken: a multi-centre study in guinea (the jiki trial, see sissoko [ ] ) and a single-centre study in freetown, sierra leone [ ] . conclusions are limited by the chosen study design and the challenges of trial implementation under the circumstances. the former, larger study did not demonstrate a treatment effect of favapiravir on mortality, whereas the latter reported survival benefit and viral load reduction in treated patients. together these results support prioritization of a randomized placebocontrolled trial of favapiravir, when the opportunity presents. there is some evidence (and a widely held belief) that an ebola-specific antibody response is protective, providing the rationale for attempted treatment and prevention with ebola virus-specific antibodies. specific monoclonal antibodies were available but in short supply and were not easily amenable to rapid scale up. one such antibody cocktail, zmapp, was initially used compassionately in repatriated patients and when increased supply became available, the only randomized control clinical trial was performed, in us, guinea, liberia and sierra leone. the results suggested that there was some evidence of treatment effect, and again this agent will certainly be a likely candidate for prioritization in any future outbreaks [ ] . other monoclonal antibodies, (zmab and mil ) were also used in selected cases as pep [ ] . due to encouraging results during the earlier kikwit outbreak (albeit in selected patients, see mupapa [ ] ) there was considerable enthusiasm for a trial of convalescent plasma and/or whole blood from evd survivors. phase ii trials were commenced in guinea and sierra leone, but neither trial recruited enough patients, and the guinea trial did not ascertain whether any neutralizing antibody was present [ , ] . additionally, a pilot study of interferon β- a for evd enrolled only patients in the intervention arm (reference konde et al plos one interferon β- a for the treatment of ebola virus disease: a historically controlled, singlearm proof-of-concept trial. it remains to be seen whether there are long term side effects or other consequences of therapeutic manipulation of the natural immune response to evd. it is difficult to assess the effect of different interventions on outcomes, due to the lack of formal studies involving rigorous prospective data collection and appropriate controls. the epidemiology of the disease and the response changed significantly, and so historical comparisons are relatively unhelpful. we have concluded that, in the absence of evidence and the lack of opportunity to generate evidence, it should be the priority to optimize supportive therapy, including intensive care therapy when available. other specific interventions may be used when they are readily accessible, likely to provide benefit based on extrapolation from other diseases, and very unlikely to do harm, in pragmatic studies. other interventions, including novel drug therapies and immunotherapies should be evaluated in randomized, adequately controlled clinical trials, prior to use. diana garde and emily headrick care for the pregnant and postpartum patient in the context of an ebola virus disease (evd) epidemic presents unique and challenging clinical, ethical and logistical considerations. since the first recognized epidemic of evd in zaire in , subsequent outbreaks have occurred in sub-saharan africa (ssa) [ ] where access to robust maternal health care services has been limited. an evd epidemic superimposed on an already weakened health system further exacerbates extremely poor outcomes for the obstetric population. in general, % of all women are expected to experience obstetric complications [ ] . the - west african evd epidemic is the largest to date, with approximately , cases in three countries-guinea, sierra leone and liberia. prior to the - evd epidemic, these countries demonstrated some of the worst health care indicators due to inadequate infrastructure, human resources and lack of access to basic medical resources [ ] [ ] [ ] [ ] . in sierra leone, it is estimated that prior to the evd epidemic, one in every women would die in childbirth-related incidents in her lifetime, [ , p. ] with the maternal mortality ratio at per , live births in -the highest in the world [ ] . in addition, all three countries fell within the lowest density of medical personnel per capita, resulting in the smallest and least-skilled healthcare workforce in the world [ ] . both the number of in-hospital deliveries and cesarean sections declined as the incidence of evd increased [ ] . ultimately, it was predicted at the end of the epidemic in west africa, that the greatest impact of evd would be on maternal health due to the loss of medical staff to ebola (physicians, midwives and nurses). by september , the three countries had lost medical personnel from their already significantly small workforce [ ] . from that data, it was estimated that there would be an increase of at least % (guinea) and as much as % (liberia) in maternal mortality [ ] . it has been asserted that women are at an increased risk for evd infection, both physiologically and socioculturally. traditionally, they are the caregivers for ill family and community members, and they responsible for burying the dead, and as such have significant potential for interaction and contact with the virus via body fluids [ ] . if a woman is pregnant during an evd epidemic, routine health care encounters for antepartum or intrapartum care places women at high risk for exposure to infected patients also seeking care. there is a higher prevalence of female medical staff, namely nurses and midwives, both inside government facilities and in the community who would then be more likely to have (knowingly and unknowingly) direct contact with positive evd patients in an epidemic. in addition, females in ssa have historically had less authority over their reproductive health and are at higher risk of gender based violence or coercion [ ] ; sexual intercourse with an infected or surviving male also places women at increased risk of infection [ ] . natural immunosuppression occurring in pregnancy [ ] may play a role in a higher acuity of illness observed in presenting obstetric patients with positive evd, contributing to very poor maternal outcomes. considering the expectation of an excess of . million pregnancies per year [ ] across guinea, sierra leone and liberia, a significant number of women who had direct contact with the virus were either pregnant or postpartum. during the - west african evd epidemic, pregnant women presenting for health care services-either for routine peripartum care or in the event of obstetric complications-often met case definition for evd (see table . ).where proactive clinical management would have been appropriate in a non-epidemic table . clinical and epidemiological factors in initial evd case definition screening epidemiological factors considerations for screening for general populations early: fever, profound weakness or malaise, headache, myalgia, arthralgia, conjunctivitis, nausea or anorexia, throat pain or difficulty swallowing, abdominal or epigastric pain, diarrhea (bloody or nonbloody) exposure/contact: infected animals, bushmeat or fruit also fed on by bats, healthcare workers/ traditional healers also treating evd, items soiled or touched by positive evd patient, deceased evd bodies sexual intercourse with evd-positive male or evd survivor late: confusion and irritability, hiccups, seizures, chest pain, diarrhea (watery or bloody), vomiting (with or without blood), skin rash, internal or external bleeding, shock, respiratory distress additional considerations for screening obstetric population vaginal bleeding of unknown origin, spontaneous abortion, premature labor and/or rupture of membranes, preterm labor, antepartum and postpartum hemorrhage, intrauterine fetal demise, stillbirth, loss of consciousness exposure to products of conception or deceased fetus of evd positive patient being a pregnant woman with history of contact with confirmed evd patient, recent evd survivor with an intact pregnancy, newborn of an evd positive mother, infant breastfed by a recent evd positive mother who library cataloguing-in-publication data [ ] setting, women were often left untreated or were provided minimal intervention by frightened medical staff working in an overwhelmed, under resourced health care system in crisis. even as the emergency response resources became more established, an unfortunate number of women were isolated based on presenting symptoms; the majority of these women ultimately tested negative for evd, yet they languished and died in evd isolation centers due to the limitations of obstetric interventions available in this setting. it is in this context that clinical care for obstetric patients in an evd setting be specifically considered. culture, health infrastructure, access to resources, geography and physiology are all complex forces that must be considered when managing individuals and populations alike. treatment of the pregnant or postpartum patient who meets case definition for evd should be offered without haste and with the highest level of quality interventions possible, while maintaining safety of healthcare workers and the community. this chapter aims to achieve the following objectives, informed by previous research on evd outbreaks and by field experiences from the to west african evd epidemic: -examine the unique risks and needs of the obstetric patient in the context of the an evd epidemic -review clinical management of the obstetric patient infected with evd as well as the unconfirmed or suspect obstetric patient being managed in a red zone (rz) setting -provide technical guidance for establishing a safe and effective setting for triage, screening, isolation and treatment of the pregnant patient and mother/baby dyads. one of the key challenges when evaluating a pregnant patient in the context of evd is that symptoms suggestive of evd infection (i.e. abdominal pain, vaginal bleeding) may mask a true obstetric emergency. conversely, the clinical presentation of what initially appears to be an obstetric complication often confounds the accurate identification of potential evd infection. however, evd infection can be the precursor to obstetric complications and a patient presenting for care may in fact require appropriate interventions for both. the basic evaluation of suspected evd patient must consider both clinical presentation (signs and symptoms) and an accurate history to evaluate risk of exposure. due to this unique overlap in symptom presentation for the pregnant patient, additional considerations for the obstetric population must be made in addition to the general screening (table . ). it is of note that not all evd-infected patients presented with or manifested a febrile state during their illness. it is estimated that only between % [ ] and % [ ] of patients actually presented with fever greater than c. likewise, patients did not regularly demonstrate coagulopathies or overt hemorrhagic symptoms [ ] , as is frequently assumed as a common presentation for a viral hemorrhagic fever, with only one study finding these as a presenting symptom in only % of patients [ ] . in the - west african evd epidemic, it was frequently observed that evdpositive pregnant patients were presenting with tachypnea and tachycardia, sometimes in the absence of any other symptoms, and could be repeatedly seen "hitting the floor," or favoring a position on the floor rather than in bed. it is postulated that this behavior may be due to agitation, or to alleviate fever by lying on a cool surface, but was routinely observed among this population [ ] . although many guidelines for screening include fever and bleeding as dominant symptoms in the algorithm, suspect cases can present without either and evd illness can be missed during initial clinical evaluation. in fact, there are multiple documented cases of pregnant women with known evd exposure and/or infection who do not manifest these common symptoms as expected. in these cases, the potential for an evd positive fetus/neonate is %, thus increasing the risk to unsuspecting healthcare workers during routine intrapartum care [ ] . the majority of obstetric complications outside of an evd epidemic involve the following: postpartum hemorrhage (pph), antepartum hemorrhage, obstructed labor, postpartum sepsis, complications of abortion, severe preeclampsia or eclampsia, ectopic pregnancy and ruptured uterus [ ] . in , approximately women in ssa died each day as a result of obstetric complications, the majority from pph [ ] . in addition, the stillbirth rate in ssa is approximately times higher than in developed countries at / [ ] . as such, an evd-negative obstetric patient can easily meet current who case definition, resulting in the isolation and testing of a high proportion of women who are actually in need of basic obstetric care. given that overlap of presenting symptoms may be commonly seen in both evd and non-evd obstetric cases, astute clinical decision making is required to ensure that obstetric patients are not being overwhelmingly screened and disproportionately isolated for evd when the absolute risk in the community is low. conversely, great effort must be made to ensure that symptomatic obstetric patients are not being treated outside of isolation when the absolute risk of evd is high. in west africa, it was estimated that only . % of the pregnant patients admitted to isolation were evd positive; the . % who were not merely needed intervention for obstetrical complications or normal delivery [ ] . epidemic: in an epidemic setting it can be argued that the likelihood of infection transmission or the public health risk from evd is greater than the risk of morbidity or mortality from obstetric complications. you must first consider general screening for the basic symptoms of evd infection, with additional symptoms to be considered for the obstetric patient (table . ): any of these additional obstetrical complications, particularly in combination with symptoms included in routine evd screening, should warrant isolation and polymerase chain reaction (pcr) testing. in addition, screening methods must capture any patient who presents to a healthcare facility who has recovered from evd with an intact pregnancy and is in labor or in the immediate postpartum period. given the absolute likelihood of viremia in products of conception from a patient who recovered from evd while pregnant, delivery must take place in isolation. in a post-epidemic setting the general screening criteria changes, but the obstetric screening considerations remain largely the same. contrary to epidemic settings, the risks of poor obstetrical outcomes are overwhelmingly thought to outweigh the risk of evd infection or transmission of disease; strong clinical judgment should be employed. in the general population, initial screening uses fever as a determinate for case definition. this tool is used for any acute hemorrhagic fever (table . ). the fever must have persisted despite treatment with appropriate medications for the symptoms (i.e. treatment for presumed malaria), prescribed by a qualified medical professional. the patients meeting criteria must be isolated and pcr tested. pregnant women pose a challenging dilemma during the initial months after an epidemic has been declared over. those who conceived during the epidemic could potentially carry an evd infected fetus into a post epidemic setting given the average weeks of gestation. in a post-epidemic setting however, one might argue for a higher level of scrutiny and clinical judgment prior to admission. the singular obstetric complication alone as criteria for admission for evd testing cannot be justified given the numbers of patients that present for care for pph, iufd and sab under non-epidemic conditions. in either an epidemic or post-epidemic setting, obstetric patients with highly concerning presenting symptoms should be admitted for testing in isolation, regardless of whether they fit the established criteria. consultation and collaboration is recommended with other obstetric providers, surveillance officers, and evd medical professionals who should be made aware of these cases. the evaluation and planning for a patient presenting with symptoms of evd is wholly dependent on whether there is a declared epidemic present, or if there are definitive laboratory-confirmed positive cases in the population. where there is any concern for evd or other hemorrhagic fevers, triage and screening should be established at the entry point to every tier of health care facility in the affected area per guidance of government mandates or international recommendation. during a declared epidemic or in cases where there is a high suspicion of infection, an obstetric-specific screening area should be staged at all peripheral health units, community clinics, and hospitals ( i.e. anywhere obstetric patient may present). all pregnant, postpartum and lactating women should have an accurate temperature taken, and basic and obstetric-specific screening questions addressed before entry to the facility. trained maternity nurses should complete the initial screening and evaluation to allow for experienced clinical judgment in this special population. ideally, screening should be operational for as many hours in a day as the facility is active. staff should have clear protocols for documenting patient information to ensure multiple opportunities for confirmation of triage status upon entry into the health care encounter. we recommend standardized forms that can be made in duplicate or triplicate for record keeping. staff should also have ways and means of communication to other colleagues so as not to leave the triage post in the event of a positive screen, an emergency in triage, or need for consultations or technical/ operational support. this station should have access to electricity or reliable lighting, and a source of water for hand washing stations and cleaning. while the triage area should ideally remain a calm environment for efficient yet thorough screening, the possibility of emergent screening is eminent. triage staff should be prepared to prioritize emergent or critical cases while adhering to screening protocol and ultimately prioritizing safety for themselves, colleagues and patients in the immediate surrounding area. patients may present to the facility in critical condition on foot, by private car or by ambulance from another facility. if the patient is unconscious or unable to give a clear history of the present condition, immediate isolation should be the most likely triage decision. if family members or an accompanying health care worker can provide a clear history that places the patient at a lower suspicion for meeting case definition, clinical judgement can be exercised judiciously. a secondary screening area can be used when staff determines that a patient is going to isolation, but more history taking and assessment must be made. an open window with a one-meter buffer can be placed between the staff area and patient secondary screening room. a patient can be removed immediately from the primary screening area and obstetric-specific information can then be gathered from safely behind the window. if the situation warrants, nursing staff can use the space in secondary screening to allow for observation to assist in determining if the patient meets case definition. when a patient enters the secondary screening, it should be considered a red zone until suspect status is otherwise ruled out, or the patient is transferred into the appropriate isolation ward and the secondary screening cleaned. in some situations, emergent or non-emergent, a thorough screening is not feasible prior to delivery and in cases of unknown history care must be administered as if the patient meets case definition. it is beneficial to design and stock the secondary screening facility to immediately turn into a safe red zone in the case that a patient exhibits an emergent illness (i.e. actively bleeding, loss of consciousness) or in cases of imminent delivery. if the patient cannot be transferred into the secondary screening area, triage nurses must have the ability to close the primary screening zone from pedestrian traffic, offering privacy to the patient, room for nurses to work and separation from the general public until the emergency is resolved. clinical and ipc staff must have ready access to all necessary materials in the triage/secondary screening area to safely and effective care for patients requiring immediate attention. we recommend the following: • nurses must have a donning and doffing area and the means to handle blood borne waste or body fluids. • delivery kits, fluid resuscitation supplies, comprehensive ppe and medications for pph should be maintained in the nursing area and access to a hospital bed in secondary screening is optimal for patient care. • there should be the means for transferring a non-ambulatory patient to either isolation or to the hospital after the appropriate screening is completed, or postpartum. this may include a wheelchair or a stretcher. there are known cases of pregnant women presenting to a health care facility in labor who do not meet case definition at admission, but who then develop higher-acuity symptoms during/after labor and are subsequently test positive for evd [ , ] . it is crucial that health care administrators, staff and supporting partners collaborate to establish and implement protocols to increase the chances of early identification, rapid isolation, adequate treatment and effective ipc in the health care facility. ongoing assessments must take place for the in-patient population throughout their stay in the hospital. there must be q-shift assessments completed to determine if a patient is showing signs of becoming ill or demonstrating the classical obstetric warning signs. medical personnel must also screen neonates post-delivery q-shift, during their entire stay and discharge instructions must offered to caregivers regarding warning signs after discharge. given the potential for a scenario in which a patient has subclinical asymptomatic infection, but passes evd to the fetus, clinicians must be watchful for and proactive in isolating and treating as soon as symptoms arise. during an active evd epidemic, every patient must be treated as potentially infected, no matter where they may suddenly require care. while care should never be withheld from a patient requiring attention, appropriate ipc measures must be available before care is delivered. given the rapid progression of obstetric emergencies and precipitous labors, rapid response protocols should be established. any area can be rapidly turned into an ad-hoc red zone. all first responders should be comfortable with ipc principles and with the concept of red zone/green zone, which can theoretically be established with or without physical barriers. multiple sets of complete ppe should be available at multiple locations in and around health care facilities and in ambulances. care should not be rendered without appropriate ppe and ipc materials. we recommend delivery kits also be easily accessed or assembled for imminent deliveries. support staff should be available to secure a perimeter around an ad-hoc red zone to maintain crowd control, for delivery of additional materials and medications, to establish a line of communication between ad-hoc red zones and surrounding areas, and to initiate the next steps of transfer into a facility once immediate care is rendered. hygienists/ipc support staff should don full ppe and prepare to decontaminate the ad-hoc red zone once the patient is stabilized and transferred. in the event of potential exposure or contamination to others in the community, every attempt to identify potential contacts is crucial for ongoing contact tracing and surveillance. while this can be difficult when an ad hoc red zone must be established in a large facility, in a crowd, or involving methods of transportation, it is crucial in the midst of an outbreak. the - west african ebola epidemic catapulted the research and development of innovative designs for the structures and materials used to combat this virulent disease. while the relative quality of infrastructure used as ebola treatment centers ranged from sticks and tarps to military grade modular isolation units to modified existing structures to multimillion dollar bsl biocontainment facilities at prestigious academic medical facilities in the united states, the guiding principles of infection prevention and control remain the same across sites. the guiding principles of an ebola treatment center include: -limited entry and exit points, for both patients, staff, materials and corpses. -double barriers between red zone and external environment. -flow of movement from green zone, to suspect case areas, to confirmed case areas, to morgue, thus reducing the risk of transmitting virus from confirmed evd positive patients to possibly uninfected patients. -multiple points for decontamination between patients -adequate distance/barriers between patients and between "suspect" and "confirmed" wards -clinical principles that prioritize safety of staff, minimizing risk of contact with infected fluids. -around-the-clock bedside care is very difficult to realize given staffing constraints and limits of length of time in ppe. regularly scheduled "rounds" to administer patient care is more feasible [ ] . these principles remain the same for an ebola treatment center serving the obstetric population. however, in our experience, we recommend the following considerations to the design and utility when caring for pregnant or laboring women in a red zone. • etcs are generally separated into suspect vs. confirmed wards, and/or "wet" versus "dry," meaning patients with active vomiting or diarrhea should be separated from those who do not to reduce the risk of transmission of highviremia fluids. we recommend that in an obstetric red zone, every attempt should be made to arrange patient beds so that actively laboring or unstable patients occupy an additional "ward," ideally one that can be visually monitored at all times. in the ob red zone setting, intrapartum patients are considered highest-risk in terms of potential of evd transmission (in known positive or unknown pcr status), but regardless of their evd status, will require the most focused care until they are stabilized. • it is likely that staff will not be able to provide hour support in the red zone, but particularly when a patient is actively laboring, every attempt should be made to schedule teams of two to rotate through "red zone rounds" to assist with labor without interruption of bedside care. deliveries can be precipitous, and forgoing constant bedside care in active labor increases the risk that simple complications (i.e. shoulder dystocia, pph) result in death. • in the event that staffing support does not allow for constant bedside care during an active labor, we highly recommend designing the ob red zone with multiple access points to visualize patients from the green zone, either through windows or utilizing camera or video recording equipment if available. being able to visually assess the status of a patient to determine the best time to don ppe for bedside care can be crucial to improving outcomes. • every red zone should be equipped with the appropriate materials to care for the obstetric patient. there are several key items that will be necessary to have in abundance: -menstrual pads and diapers (adult and infant) -infant formula and feeding cups -cotton sheets (or suitable substitute) to cover patient for warmth and privacy, also to anticipate multiple bed-linen changes, and several rags, towels, linens for cleaning large amounts of blood/amniotic fluid. -bassinette which can serve as sleep area for neonate or set up as neonatal resuscitation surface post delivery (must have cleanable surface) -suture materials, needle holder, blunt tipped scissors, speculum or retractor -manual vacuum extractor or forceps -individual blood pressure cuff and thermometer at each bedside, able to be sanitized. -sharps container at each bedside -iv poles, both and short (short for patient who must be placed on the floor for safety) -bell, intercom or other means of calling for assistance. this is particularly helpful for women in early stages of labor who may not require constant monitoring to alert staff that assistance is needed. -wall clock to monitor contraction intervals, as well as time limits for staff in the red zone. -scale for infant weights or for measuring maternal blood loss -ready-made and easily accessible kits with necessary equipment to rapidly manage normal deliveries, postpartum hemorrhage, and eclampsia/seizures the acuity and complexity of patients entering into the red zone is such that a standard medication protocol is warranted. given the lack of immediate diagnostic capacity in many settings, it is recommended that all patients receive empiric treatment of antibiotics, antiprotozoal and antimalarial medications until bacterial, amoebic or malarial infections can be definitively ruled out, or the entire course completed. even in the case of evd, one cannot rule out co-infection with malaria or other common infectious disease. as such, evd suspect and positive patients should be continued on all medications unless testing confirms absence of co-infection. clearly, it would be optimal to have an extensive medication formulary at the disposal of clinical staff in an epidemic, however the historical outbreaks occurring in low resource countries have forced makeshift pharmaceutical supply. the following are suggestions for coverage of the potential needs in isolation or treatment centers. planning should include at minimum medications from the following categories. all medications listed are from the who model list of essential medicines [ ] , unless otherwise noted. clinical judgment must be made as to the relative benefits and risks involved and the acuity of the individual patient when choosing medications (table . ). for purposes of simplicity and as a model for the ideal facility, the following will be addressed as if both suspect and confirmed cases are in isolated and treated within the same site. at admission, it must be determined where the patient should be placed within the unit based on their status. "wet" suspect patients, or those with active bleeding, vomiting or diarrhea should be separated from "dry" suspect patients. all suspect women awaiting test results should be physically separated from probable confirmed patients. laboring patients should be given privacy and placed inside intrapartum rooms for delivery, containment of body fluids and a higher level of care and observation. infants should be with their mothers and not in a nursery. bassinet sharing must be avoided. it is critical for every patient who enters into an isolation or treatment center, that complete demographic and symptom history information be completed at the time of admission for care planning, data collection and tracking purposes. first name, last name, and birthdate should be verified and patients given a wrist name band including those three identifiers. patient information can be entered onto a whiteboard or other central documentation record for clinical planning with the following information: bed number, name (first and last), age, birthdate, pregnancy status (pregnant and gestational age, postpartum or lactating), presenting symptoms, and date of onset of symptoms. this record can also include pregnancy outcomes that are updated in real-time (i.e. delivery date and time, gender of neonate, complications, etc.). it is advisable to have an admission book, or means of keeping patient status updated and relevant data logged. the goal is that all staff members can quickly assess and interpret the status of all patients in the etc, as status can change rapidly. another whiteboard or central documentation record can also be used to track lab tests completed (date and time), when the next confirmatory tests are due and results. in order to create a care plan for individual patients, a complete head to toe assessment must be completed to the best ability of the clinician, given time and patient load constraints. information that should be collected can be divided into two categories-objective and subjective. a clinician with experience in obstetric care should collect the objective information. the subjective information is dependent on patient consciousness, the ability of a patient to be an accurate historian or in some cases must be pieced together from family members. the clinician inside the red zone is responsible for collecting gaps in history that has not been addressed before admission (table . ). all information must be documented in patient charts after each assessment in the red zone and on the central documentation record/whiteboard. patients in labor should have a partograph started if over - cm dilation. to date, pcr has been the testing method of choice for evd infections. approval for use of a rapid screening test (rst) or genexpert for evd would allow access to results that could rule out evd quickly. choice of testing method must be made according to current international standards, national regulations and pharmacy board approvals. all patients entering into the center should be pcr tested on admission. if the symptom onset is less than h, then a second test is needed at or after the h mark. suspect and confirmed patients having either a spontaneous abortion or iufd must have products of conception swabbed and tested (fetus, placenta-fetal side, associated tissue or amniotic fluid). an neonate delivered in isolation, or admitted with a suspect patient must also be tested. a patient who is deceased prior to serum collection should have oral swabs collected prior to burial. iufd at full term can also have oral swabs collected. like any other evd suspect or confirmed patient, pregnant, postpartum or lactating women must be assessed and treated based on presenting symptoms. given the nature of fluid loss, offer appropriate replacement fluids (ors or iv/io) based on the severity of dehydration and level of consciousness. consider differential diagnoses and offer antibiotic and antimalarial therapy as discussed above. symptomatic relief must also be included in the care plan for pain, nausea, vomiting, agitation etc. obstetrical care in the context of evd has historically been limited to expected management given extremely high viral load present in amniotic fluid, blood, and placental tissue. as a result the inherent risk to health care workers it was determined to be too high for interventional care. the following were considered high risk in the past and healthcare workers were cautioned against engaging in: cesarean section, artificial rupture of membranes (arom), episiotomy or deinfibulation of scarring related to female genital mutilation, manual vacuum aspiration, manual removal of a retained placenta, suturing, vacuum extraction, and craniotomy in the case of obstructed labor. anticipated delivery in isolation should be managed with caution ensuring the utmost safety of staff while offering the highest level of care to the patient and her fetus. adequate staffing numbers and skill level and immediate availability of needed delivery supplies and medications will eliminate some of the risks associated with deliveries in a limited resource setting. in serious cases where life is threatened or suffering is unmanaged, a higher level of intervention should be considered when qualified staff are present, adequate supplies are on hand and ipc measures can be adhered to. in this way, risks can be mediated and the potential for survival increased. for management of all deliveries in the red zone, protocols must be created with respect to the local ministry of health clinical guidelines and who recommendations for ob care in limited resource settings. additionally, the following considerations must be made to care for patients with evd filovirus or other hemorrhagic fevers: • an adequate intrapartum setting must be prepared before delivery to decrease the risk to staff and patients in the red zone. safety must always be a priority and clinicians must not place themselves at risk in the event a lack of appropriate water, lighting, or ppe should occur. • red zone staff should prepare the bedside when there is an impending delivery and have iv fluids, delivery kit, resuscitation equipment and neonate blanket and bedding at the ready. • staffing should be adequate for deliveries; ideally, there should be a nurse or midwife for the delivery, a nurse for the neonate and one other clinical staff member to monitor ipc and assist where needed. presence of a hygienist is also advisable. roles should be assigned prior to entry into the red zone. • a second team in the green zone must be ready and able to relieve red zone staff when they are exiting and there must be a system of report to update status of the patient before the change of shift. if able, the exiting ipc clinician should update the incoming team before they enter. • there must always be staff in the green zone to hand in needed medications, consult and support red zone clinicians. the green zone staff must help to monitor total time in the red zone and give adequate warning when doffing is required. a "sign in" whiteboard at the entrance to the red zone area allows for accurate monitoring of time in ppe and identification, location and duties of staff in the red zone. -it is optimal for clinical staff to visualize laboring patients from the green zone if there are not enough staff for round the clock care in ppe. a communication tool is also advised so that the patient can call for help if needed, or give status reports to staff. • elbow length gynecologic gloves are preferred for deliveries. in addition to standard ppe, a heavier and thick reusable apron is recommended for the delivering clinician to protect the front of the coverall from body fluid, and to reduce the movement of a lighter, thinner apron. have all needed ppe in the red zone and readily available. -treat all body fluids as potentially infected -place iv before delivery if possible in anticipation of likely ivf resuscitation and to reduce risks to staff associated with an urgent/emergent iv placement. • fresh . % chlorine must be available for immediate decontamination of soiled gloves and gown. hands must be washed or outer gloves changes between procedures. • limit the number of vaginal exams during labor to the initial assessment and intermittent progress checks q h if needed, or the to fewest number possible. • a partograph and/or detailed charting and adequate care planning must be maintained so as to monitor labor progression and anticipate potential interventions for complications. • regularly monitor fetal heart rate or movement. • refrain from using fundal pressure during second stage • a clear plastic sheet should be used as a drape during delivery to separate the clinician from the neonate and placenta. the delivering clinician is avoid sitting or standing at the end of the bed or between the legs of the laboring patient to limit contact with blood or amniotic fluid exposure. • limit the number of sharps in the red zone. use blunt tipped scissors if available for cord cutting. prioritize single use instruments over multi-use. if multi-use instruments are used, a system for cleaning must be employed. a rinse in . % chlorine will ensure adequate decontamination. a fresh water rinse and immediate drying will delay corrosion of metal instruments. if available, an autoclave is optimal. • suturing should be available and employed only when adequate lighting and experienced staffing are available and only in cases where the patient is cooperative (not agitated) and there is a risk of negative outcome without intervention. -blood loss and uterine tone should be monitored closely after every delivery, regardless of gestation. • po medications are preferred, but if needed progress to iv, im or io. all postpartum patients should have iu of slow iv push or im oxytocin (after confirmation of single fetus) to decrease the chances of pph. • if delivery of live baby (or with retained placenta), tie off and cut the cord under plastic. in cases of fetal demise, leave the cord intact, deliver the placenta and place both placenta and fetus together into a body bag, using recommended ipc measures. • a team of postpartum clinicians should be available to monitor vitals and infant transition in the hours after delivery -referral for hiv or tb testing or pmtct services should be offered at discharge if there is a known or suspected secondary infection. given the nature of a viral hemorrhagic fever superimposed on pregnancy, the likelihood of obstetric complications and coagulopathy is very high. safety of staff members must be prioritized, however, we recommend the consideration that more interventions may be appropriately rendered to improve patient outcomes than were recommended in the - evd outbreak. • adequate iv fluids must be on hand for volume resuscitation in high acuity cases. • consider induction of labor in emergent cases only; otherwise, defer induction if a suspect case is highly suspicious of having evd. this is in an effort to reduce unnecessary exposure of staff to body fluids. • deinfibulation of type female genital mutilation (fgm) is discouraged, but may be performed if it is considered a life saving measure. if proceeding with procedure, perform at the patient's side, under plastic sheeting and with adequate anesthesia or pain relief. • perform fundal massage (with support of lower uterine segment) and iu of oxytocin in l of iv fluids ( gtt per minute) for initial pph management and be prepared to offer higher levels of intervention if bleeding persists, including: external aortic compression and uterine balloon tamponade. -in cases of antepartum or postpartum hemorrhage, consider having an established system for basic blood typing within the unit and a process in place for collection and administration of blood products. no suspect or confirmed patient blood can leave the unit unless a process is in place to transfer to a evd specific lab. staff must be trained to type patient blood and to monitor for transfusion reactions. inadequate training would disqualify a treatment center from transfusing. • patients who are suspect and acutely ill are often placed in situations that are life threatening while they wait for pcr results. consider establishing a site for isolation surgery (dependent on trained personnel, equipment and adherence to ipc measures) so that patient needs can be addressed in emergencies and the option of cesarean section be made available. • consider administration of nifedipine over terbutaline (may have more serious side effects and requires higher level of monitoring) for delay of early onset preterm labor or onset of uterine hyperstimulation. consider antepartum corticosteroid (acs) administration in cases where preterm delivery ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) weeks gestation) appears to be unavoidable. • proactively treat prom or pprom with prophylactic antibiotics. • do not delay treatment of hypertensive emergencies. offer antihypertensives (po or iv) if systolic exceeds and diastolic exceeds and monitor regularly. address severe preeclampsia or eclampsia immediately with im magnesium sulfate and continue until h post-delivery or last seizure (whichever is later). the risk of fluid overload must be balanced with the propensity of evd patients to be fluid depleted and anuric. monitor for symptoms of pulmonary edema and defer diuretics unless severe edema [ ] . rapid delivery can resolve symptoms of eclampsia and induction or augmentation should be considered. • in cases of iufd, deliver as with a live infant under plastic sheeting. in many cases, symptoms of infection are present and mimic evd, particularly if labor has been delayed or obstructed. treat with antibiotics for chorioamnionitis and monitor. induce or augment labor to expedite delivery if the risk of puerperal sepsis is high. given the extremely high risk of fetal death with positive evd mothers, pregnancies must be monitored and ultimately delivered in isolation or in an etu. even if the patient is recovered, her products of conception will have high viral load and must be treated as infectious waste. • spontaneous abortions must also be treated with suspicion and poc from suspect or positive patients treated as infectious waste. • vacuum delivery and episiotomy can be considered for obstructed labor when it is believed to be a life saving measure. ipc measures should be maintained at all times. referral for cesarean should be made when available, if failed assisted delivery. • in the case surgical intervention is needed and not available, all attempts at supportive care and potentially palliative care must be administered until lab results are returned. transfer of a non-infected patient with confirmed negative pcr to non-isolation facility can be arranged when lab results are returned. this patient who has been identified as not having filovirus must be advocated for outside of isolation or treatment units and reassurance given to medical staff that they are uninfected and safe to be operated on. • confirmed evd-positive patients with no access to surgery must stay in the treatment center until recovery and two confirmed negative results have been received. the fetus, regardless of gestation, will very likely not survive and will need to be delivered within the isolation facility. -depending on the location of the epidemic, there may be access to high intervention medical care and drug therapy for neonates born from an evd positive mother and though the fatality rate has historically been almost %, priority for should be given to advances in clinical care and vaccines. however, in the absence of adequate interventions, the option of therapeutic medical abortion before discharge should be offered if an evd positive patient has an intact pregnancy, the patient lives far away from a evd treatment center and there is a risk that she will not return for delivery (thereby risking further infection in the community). given that the majority of women entering into the etc will be evd negative, the majority of care should mimic the expectations for infant care in a non-epidemic setting. fetal monitoring during labor and delivery should be provided for early detection of complications and immediate care of the infant is essential to ensure optimal outcomes and reduce the risk of infant mortality. • immediately after delivery, vigorously stimulate and dry the neonate • oropharyngeal/nasopharyngeal suction only if secretions suction only if secretions are obstructing the airway; there is no need to suction a vigorous neonate, even if meconium present • perform basic assessment (airway, breathing, circulation) and offer resuscitation if needed • allow delayed cord clamping and cutting in non-emergent settings, tie and cut cord under plastic sheet to minimize contact with blood • clean and dry infant and allow skin to skin/kangaroo care and bonding if the mother is capable • assess initial apgar score and then complete routine vital signs: respiration rate, heart rate (umbilicus or brachial pulse) and temperature q min  after delivery and q shift (at least with every assessment of mother thereafter). complete newborn assessments as thoroughly as possible given time restraints in ppe and check for jaundice, tone, retractions and feeding. stethoscopes cannot be utilized in a red zone. • ensure that the infant bassinet is covered with mosquito netting to decrease the risk of malaria infection • offer vitamin k injection im ( mg) at birth, ophthalmic tetracycline ointment bilaterally, and chlorhexidine cord care per who recommendations • delay washing for h is possible and dress infant in weather-suitable layers ( - layers more than adults) to stabilize body temperature. • offer other treatments based on individual symptoms-consider im antibiotic treatment for bacteremia for days if concerns regarding infection survival of neonates delivered to evd positive patients in or out of an etu is close to % mortality rate. at the end of the - west african epidemic, one documented infant of a deceased evd positive patient survived after an intensive antibody, broad spectrum antiviral and antibiotic regimen [ ] . one can assume that a neonate is exposed to filovirus in utero, during delivery or during breastfeeding (though it has appeared based on documented cases of live births that neonates seroconvert shortly after delivery with unknown data around the impact of breastfeeding [ ] ). recommendations then include keeping the mother and infant as a treatment dyad and allow the mother to care for the infant if able. communication with the mother about her evd status and expected outcome of the neonate should occur as early as possible, with adequate psychosocial support as needed. there are several factors that must be considered when reviewing recommendations for breastfeeding a neonate after delivery in an isolation setting and before maternal pcr results are obtained. in resource low areas, the risk of unsanitary water to make powder formula, the unavailability of ready to use infant formula (ruif), the lack of hygienic means to sterilize bottles, or the prohibitive cost to families to obtain artificial feeding or animal milk products for the neonate for up to years after delivery must be weighed with the immediate risk of continued breastfeeding and exposure to evd. who recommends that in cases where the mother is symptomatic and awaiting results that her breastfeeding be suspended. in these cases a discussion with the patient about the risks, benefits and options must be had. where the mother is unable to give informed consent one way or the other, family members must be brought into the conversation and clinical decisions be made also taking into account the current prevalence of infection in the community. if the patient's result is positive, it can be assumed that the neonate will be positive. there are questions about the initiation of breastfeeding and whether the infant is already infected and would ( ) benefit from any maternal antibodies, ( ) will get an increased viral load through breastfeeding, or ( ) be likely to die regardless of feeding. who recommends suspending breastfeeding and starting ruif (ready to use infant formula) until breast milk samples test negative  by pcr testing after which the mother should be encouraged to initiate or resume breastfeeding exclusively for at least months. for patients who suspend breastfeeding until results are returned, interim supply can be maintained with pumping. however, all expressed milk must be treated as contaminated material and discarded per appropriate ipc protocols. if the patient expires during or after delivery but prior to maternal serum testing, oral swabs of the corpse are to collected prior to burial. collect a serum sample for pcr testing of the neonate as soon as possible , however note that the infant must be in the care of isolation facility for days following delivery. a neonate can be infectious but present as being asymptomatic days prior to becoming ill and even then symptoms are atypical or non-specific. accounts of live newborns delivered to positive mothers were all documented to be deceased within the th day of life [ ] . the -day cut off allows for monitoring for the entire contact exposure period. if neonate is positive, treat per pediatric evd protocol or arrange transfer to an appropriate treatment facility via local government regulations. planning the psychosocial impact of the - west africa ebola epidemic is an immeasurable burden for thousands of people. a common sentiment often expressed both from patients admitted to etus and health care workers alike was the dehumanization and trauma of being isolated. the human element of direct patient care was covered by multiple layers of plastic, only eyes visible behind foggy masks. while novel efforts to humanize health care workers rapidly spread by word of mouth among first responders, the experience of being cared for in an isolation center is undeniably traumatic. we strongly advocate for early and robust psychosocial resources as part of a comprehensive evd response. care for the pregnant patient also requires unique psychosocial considerations. while practices may vary across cultures, childbirth is a global phenomenon laden with tradition, ritual and social norms. universally, the laboring woman is at her strongest, and yet at her most vulnerable. effort should be taken to understand and support the unique sociocultural norms surrounding pregnancy and birth in a way that maintains dignity in delivery while adhering to all safety and ipc protocol in the context of evd care. in times of crisis, it may be common for the quality of patient care to suffer as safety or allocation of resources is prioritized. we assert, however, that quality can be incorporated into emergency response service delivery in a way that does not jeopardize safety or waste valuable resources. discharge planning and patient education are components of emergency response service delivery that may be neglected in the height of an emergency, but in the context of evd, these practices can be a crucial component to breaking the chain of transmission as well as improving the overall quality of patient care beyond the etu. the obstetric population has unique needs upon discharge from an evd treatment or isolation facility that should be incorporated into the development and implementation of any program working with women of reproductive age. resources and protocols should be developed early so that staff are prepared to guide patients when they are discharged from the facility. all patients discharged from a red zone should receive clear instructions that they are, by default, considered possible contacts and should monitor their signs and symptoms for days after discharge. examples of unique obstetric patient pathways are summarized in table . . the development of clinical guidelines and practical health care delivery strategies to address the unique needs of evd survivors presented grand challenges for the community serving guinea, sierra leone and liberia in the recovery phase of the - west african evd epidemic. even verifying the number of evd survivors in west africa is a daunting, occasionally political task, but estimates are currently that out of , documented cases of evd, there are approximately , survivors [ ] . to date, there are no strong data to approximate how many of those survivors have become pregnant since recovering from evd, but it may be asserted that the pregnant evd survivor represents the nexus of vulnerability. in , before the a patient should be aware that these are similar presentations and may result in repeat isolation evd epidemic, sierra leone had a baseline maternal mortality ratio of deaths out of every , deaths [ ] ; that number has almost certainly risen, with some estimates by as much as % simply by virtue of the decimated health care system and decreased utilization of services [ ] . combining these baseline maternal health indicators with the pervasive stigmatization and fear of pregnant evd survivors lends an extraordinarily high risk for neglect and mistreatment of the pregnant evd patient, despite the fact that there have been no data to show active virus in the amniotic fluid or products of conception in the subsequent pregnancies of women who survived evd. it should be noted that the risk for stigma affecting care for evd survivors is not limited to the west african nations where the outbreak occurred; a case study detailing management of a pregnant evd survivor planning to deliver in the united states reports marked discomfort and concern from hospital staff despite no evidence of risk for transmission of virus [ ] . furthermore, there are limited data about subsequent pregnancy outcomes for women who became pregnant after surviving evd, with a small cohort study in liberia showing a slightly higher incidence of miscarriage or stillbirth in liberian evd survivors as compared to the overall rate in both the developed and developing world [ ] . however, national data for baseline miscarriage/stillbirth rates are not available in liberia, sierra leone or guinea, making data specifically reflecting the evd survivor population murky. recommendations addressing breastfeeding for evd survivors in subsequent pregnancies were initially limited due to lack of data regarding viral persistence in breastmilk. anecdotal evidence suggests that ebola virus may persist for several months in breastmilk of survivors, but breastmilk was not routinely included in the major viral persistence studies conducted in the immediate post-epidemic period. there are no known cases of a breastfeeding infant presenting with evd contracted from a lactating mother. given the overwhelming benefit to breastfeeding, particularly in resource-poor settings, current cdc guidelines support routine breastfeeding of the neonate born to evd survivors, with case-by-case evaluation to neonates born to suspect or confirmed evd patients [ ] . there are multiple circumstances complicating the approach to and delivery of quality care for the pregnant evd survivor, largely due to emerging research regarding viral persistence, clinical sequelae in evd survivors and sociologic trends of stigma and access to resources for pregnant evd survivors in their communities. with the data available, we support the following recommendations: • evd survivors presenting with subsequent pregnancy outside of a known evd epidemic should be treated as a non-infected patient. antepartum and intrapartum care should not be delivered with any more ppe than would be used for a non-survivor patient (universal precautions). • status as an evd survivor should be considered as a relevant part the patient's history to inform any abnormal clinical presentation, and treated with astute clinical judgement. other key components of a thorough history taking for a pregnant evd survivor include: survivor status of the father of the baby, any recent illness/complications, social support status. • the heightened vulnerability of a pregnant evd survivor should inform a broader and more comprehensive approach to high-quality antepartum, intrapartum and post-partum care. treatment of the pregnant or postpartum patient who meets case definition for evd is controversial and is often an ethically charged debate due to the overlap in clinical presentation of evd and obstetric complications. the - west africa ebola epidemic illuminated the desperate need for adequate preparedness for infectious disease outbreaks in the obstetric population, with dedicated protocols, adequate training, and unique considerations for these extremely vulnerable patients. the safety and protection of the healthcare worker must be balanced with the commitment to deliver the highest degree of quality clinical intervention possible for the pregnant patient, with the theoretical risk of transmission of evd incorporated into every aspect of clinical and care management. we recommend that the lessons learned from the - west african epidemic, where an unknown, yet unfathomable number of evd negative women and infants lost their lives in ebola treatment centers due to inadequate obstetric care, be considered in the development of all future emergency preparedness and response protocols. with committed partners implementing informed protocols, safe and high-quality maternal/child health can and should be prioritized in the midst of an emergency. nearly children were confirmed or suspected to be infected with evd during the west african - outbreak, just under % of the total [ ] . it appears that in this as with previous outbreaks, confirmed diagnoses were fewer in children than adults [ ] [ ] [ ] . the reasons underlying this apparent sparing of children are poorly understood. firstly, it could be that diagnoses are being missed, due to underreporting or poor diagnostic sensitivity in children [ , ] . it is possible that against a background of high infant mortality as with most countries affected by evd, and fear of seeking health care during an outbreak parents did not bring their unwell children for testing [ ] . alternatively, it may be that the diagnostic tests such as both pcr (polymerase chain reaction for evd dna or serological testing) were less sensitive for small children [ ] . for example, small children, particularly infants, are often challenging to take blood samples from so it may be that smaller samples were sent, or that less sensitive mouth swabs were used for pcr as an alternative early in the outbreak [ ] . however, the difference may be true biological sparing of children, where children are either less exposed or less vulnerable to exposure, or finally that children were more likely to have asymptomatic infection. from glynn et al.'s study of seroprevalence of evd immunoglobulin g (igg, evidence of previous infection) in households of evd survivors, they found no evidence of asymptomatic infections in children under years of age, and a slight excess of symptomatic undiagnosed infections in younger children: i.e. it appears that younger children were slightly more likely not to be taken to hospital despite symptoms [ ] . bower et al. investigated age-specific attack rates in the same cohort of evd survivor households in sierra leone, and found that after adjustment for exposure type, children and adolescents aged - years were less vulnerable to infection than either younger children or adults [ ] . therefore it appears from available evidence that in the west african evd outbreak at least, the apparent sparing of children was due to a combination of younger children not being brought for medical attention and true biological sparing in older children and adolescents, the mechanisms for which remain to be explained. routes of exposure are similar to adults with the additional exposure of breast milk for infants, and vertical transmission from mother to neonate (see obstetric chapter). it appears that close contact with a sick mother/primary caregiver is a key risk factor in children over and above other household or community exposures [ ] . regarding breast feeding, ebola virus has been detected in breast milk up to months post-infection [ ] [ ] [ ] . indeed, in one case, investigation into the death of a -month old infant from evd led to the discovery of ebola virus in the mother's breast milk although the mother had had no preceding symptoms [ ] . however, bower et al.'s study of mother-child pairs (children aged < years) found no excess risk from breast feeding over and above contact with a sick mother [ ] . contact with an evd-infected mother was by far the greatest risk for the child, risk ratio (rr) compared with infections in the same household excluding mother . , % confidence interval (ci) . - . , p < . ) [ ] . interestingly, household crowding and sanitation had little impact on transmission risk, and none of the children included had contact with a dead body, indicating close proximity to the mother/primary caregiver as the most important causal factor in acquisition of evd. the authors therefore agree with current who guidelines that asymptomatic infants and children should be separated from infected mothers to limit onward transmission [ , ] . regarding children themselves as sources of the virus, the data is conflicting. one modelling study based on data from burials indicated that children might be "super-spreaders" of the virus, but this has not been substantiated by epidemiological data from liberia or sierra leone [ ] . in liberia, a contact tracing study showed no difference between children and adults in terms of transmission, and a study of transmission chains indicated that children were less likely to pass on the virus [ , ] . this was mirrored in sierra leone where children were more likely to be infected in later generations within households, rather than being the primary source within a household [ ] . it seems likely therefore that children may be less, rather than more likely to transmit the infection compared to adults. in terms of mortality, infants are the most vulnerable, with case fatality rates (cfrs) varying between and % [ ] [ ] [ ] [ ] . the prognosis improves with age, such that mid-late teenagers have amongst the lowest case fatality rates. table . shows cfrs for children in studies from both the west african and prior outbreaks by age. risk factors for mortality are discussed further below. evd is notoriously non-specific in presentation, particularly in children. indeed, even fever which was key to the who clinical case definition in the west african outbreak was absent in - % of cases in three studies [ , [ ] [ ] [ ] . in most studies from the west african and previous outbreaks, features in children have included (in order of frequency) fever ( - %), fatigue/weakness ( - %), appetite loss ( - %), vomiting ( - %) and diarrhoea ( - %) [ ] [ ] [ ] [ ] ] . abdominal, muscle, joint and chest pain as well as headaches have been reported in - %, although in younger children pain is difficult to localise and so recording of pain from various body sites has been compounded into the symptom of generalised distress, seen in % of a younger cohort [ ] . conjunctivitis was recorded in - % and hiccoughs in - % [ , , , ] . difficulty breathing and swallowing were seen approximately - % of patients [ , , ] . bleeding from various body sites tended to be rarer in the west african outbreak in children than previous outbreaks ( - % compared with %) [ , , , ] , although two cohort studies recorded bleeding in % [ , ] , and a large study of guinean children recorded bleeding in % [ ] . interestingly, one younger cohort (children aged up to years) recorded cough in up to % of children, although this was less frequently seen in other cohorts [ ] . blood tests have revealed dramatic leucocytosis, deranged liver and renal function alongside raised inflammatory markers (e.g. c-reactive protein) particularly in children who died [ , ] . hypoglycaemia, often severe, was common among both children who died ( %) and those who survived ( %) in one cohort [ ] . more detailed description of electrolyte and haematological disturbances over the course of disease can be seen in fig. . [ the mean duration of incubation of evd is shortest in younger children: estimated to be week in children < year compared to . days in children aged - years [ ] . similarly, duration from symptom onset to death is shortest in younger children-under days in those < year, compared with nearly days in those aged - years [ ] . however, care must be taken with these estimates as many children were admitted unaccompanied to treatment facilities, so data regarding [ ] symptom duration may be unreliable particularly in younger children. duration between symptom onset to attendance was days [ ] . time from presentation at a treatment facility to death can also be short (a median of days in one study) so there is a small window for intervention [ ] . features at admission that are consistently associated independently with mortality across several studies include younger age and a high viral load (low cycle threshold (ct) with a viral polymerase chain reaction) as with mixed age cohorts [ , - , , , , ] . shah et al. record a hazard ratio of . ( % confidence interval . - . ) for death with a ct value < at admission [ ] . however, in interpreting viral ct values, discrepancies between laboratories and assays used should be borne in mind, as there is currently no universally used assay. bleeding at admission and diarrhoea have also been reported to be associated with an increased risk of death [ , ] . finally, in mixed age cohorts, concomitant infection with malaria has also been significantly associated with mortality [ ] . during admission, development of bleeding, shortness of breath and diarrhoea at any point are all independently associated with mortality, as well as tachycardia within the first week of admission [ ] . dysphagia was more common those who died and in shah et al.'s younger cohort (children under years), hiccoughs, confusion and bleeding were only present in children who died [ ] . for those patients who recovered, there was a period of defervescence over - days [ ] . no children died after day of admission in one study [ ] . median duration of admission those who survived varies between and weeks [ , ] . palich et al. have thoroughly documented the progress of a year old with severe evd managed at a treatment centre with facilities of laboratory monitoring and intravenous fluid and electrolyte replacement. late complications during admission include tonic-clonic seizures, which can be prolonged and severe [ , ] . in at least two cases, children were left with severe disabilities after a prolonged seizure including blindness and paraplegia [ ] (howlett et al. in review). in bower et al.'s study of late deaths within a cohort of evd survivors, one year old and one year old died after discharge from an ebola treatment centre [ ] . the year old had symptoms consistent with tuberculosis, although also had a post-mortem mouth swab that was borderline positive for ebola virus [ ] . the year old died weeks after discharge with weight loss, night sweats and dysphagia with a post-mortem swab negative for ebola virus [ ] . it appears that true recrudescence of virus as has been seen in adult patients may be very rare although possible [ , ] as can be seen by both the breadth of symptoms exhibited by children with evd, the variations in frequency of symptoms between cohorts even within the west african outbreak, and the non-specificity of these symptoms against a backdrop of high malaria prevalence and other childhood illnesses, the clinical case definition for evd is key. a sensitive and specific clinical case definition for evd in children would allow rapid access to appropriate treatment for children with evd, crucial when early mortality is so high, and also protect children without evd (with a different illness) from exposure to evd while awaiting laboratory test confirmation. to date there has been only one attempt at deriving a paediatric-specific case definition using multicentre data on over children from the west african outbreak, and this case definition has not yet been validated on wider datasets [ ] . it also does not include malaria rapid diagnostic test results which have been shown to be an important discriminator in a mixed age study [ ] . however, these limitations aside, the paediatric ebola predictive score (pep) score derived had excellent discrimination (area under receiver operating characteristics curve (auroc) ¼ . ). the scores for each clinical feature within the score are shown in table . , along with the coefficient from the multivariable model used to derive them and associated p values. as the score has not yet been externally validated, it is presented here for information rather than recommendation for use. it is envisaged that the pep score could be used together with evd rapid diagnostic tests, several of which were trialled during the outbreak, to expedite rapid accurate diagnosis of evd [ , ] in the stressful environment of an evd outbreak, the needs of children can be overlooked. certain considerations should be planned for in advance to ensure initial assessment for emergency clinical signs should take place using the emergency triage and assessment treatment (etat) algorithm for children [ ] . assessment for dehydration is key. weighing can be a challenge in facilities with limited resources, so we would suggest using a set of scales within a ziplock plastic bag (or similar) to promote easy cleaning, prevent contamination and prolong the lifespan of the scales when being cleaned with high concentration chlorine. signs of severe or moderate dehydration should be assessed clinically on admission and at least daily (preferably more frequently during the gastrointestinal phases of disease) during admission as per guidelines in the who pocket book of hospital care for children [ ] . pain and distress is common in children with evd and should be specifically assessed for and treated both at initial admission and on reassessment. blood should be taken for evd pcr as per who recommendations for exposure prone procedures, ideally by at least two staff [ ] . this is particularly important for children who need to be held still during phlebotomy. a malarial rdt should be performed if possible in high prevalence areas, as coinfection is not infrequent [ , ] . a glucose test should also be performed as a priority if feasible. any initial emergency clinical features noted during etat assessment should be managed as per the relevant treatment algorithm. placing a laminated version of the algorithm on the wall in triage will prove useful for treating clinicians. fever should be managed with antipyretics dosed as per weight/age, and again a laminated list of age/weight appropriate commonly used medications will prove useful for clinical staff both in and outside the "red zone". adequate hydration is a mainstay of therapy for those with both mild and severe evd. all children should be offered oral rehydration solution and be supported to drink it, either by a caregiver or a dedicated staff member as they may be too weak to drink it themselves [ ] . if the child is severely dehydrated or malnourished, or unable to tolerate oral fluids, intravenous fluid resuscitation and maintenance will be needed. this should be carried out according to the presence/absence of shock, severe malnutrition and severe anaemia according to the detailed protocols in the who pocket guide to clinical management of patients with viral haemorrhagic fever. these include recommendations for the volume and rate of fluid replacement and are not reproduced here in the interests of space, but we recommend that laminated versions of the fluid replacement protocols be available both in the "red zone" and outside where fluids and medications are prepared and prescribed [ ] . in brief, the three signs of shock considered are: cold extremities, weak and fast pulse and a capillary refill time of over s; severe anaemia is diagnosed with a haematocrit < or a haemoglobin less than g/dl; and severe acute malnutrition is diagnosed with a muac of < mm [ ] . although in the context of large gastrointestinal fluid losses, the benefits of intravenous fluid resuscitation is unequivocal and recommended by the who, fluid resuscitation should ideally be carried out with input/output monitoring and using a paediatric giving set [ ] . aggressive fluid resuscitation in african children with signs of severe infection (excluding gastrointestinal infections) is not proven to be safe, so every effort should be made to monitor both the volume of fluid given and the clinical impact on the child [ ] . ongoing assessment of hydration status is therefore key, and should be planned for in daily staffing allocations. if possible, electrolytes should also be monitored and abnormalities corrected, as large derangements in sodium, potassium and calcium have all been seen in children with evd [ , ] . hypoglycaemia has been demonstrated to be common in children with evd and should be monitored for as a priority if feasible, but if monitoring is not feasible, glucose should be given intravenously empirically in the case of seizure, coma or lethargy [ ] . five percent dextrose should be used in all maintenance fluids [ ] . for persistent vomiting, ondansetron (or if unavailable, promethazine, though with care to monitor for extra pyramidal side effects) may limit symptoms and permit oral intake [ ] . if a malarial rdt is not available or the result is positive, children should receive a weight-or age-appropriate dose of artesunate combination therapy (act) or intravenous/intramuscular artesunate if there are signs of severe malaria for at least hours followed by a day course of oral act [ ] . owing to the overlap of symptoms of evd with sepsis, it is both the who and our recommendation that all children under years of age admitted with suspect evd should be treated with empirical antibiotics on admission. who guidelines are that all under s should receive intravenous or intramuscular broad spectrum antibiotics (e.g. ceftriaxone), although evidence is limited as to whether in relatively well younger children parentral antimicrobials will provide a benefit over enteral [ ] . for older children, the decision to start antibiotics lies with the treating clinician as evidence is lacking, but the local prevalence of other common childhood illnesses such as pneumonia and gastroenteritis should be taken into consideration. if used locally, the empirical treatment guidelines laid out in the who pocket book of hospital care for children and the integrated management of neonatal and childhood illness should be utilised [ ] . all those receiving antiretroviral or antituberculous therapy should continue it, and restart as soon as possible if treatment is interrupted. pain and distress has been noted frequently in children with evd (see section on clinical features at presentation and disease progression) and should be managed expectantly with age/weight appropriate doses of simple analgesia (paracetamol), or opiates (tramadol followed by morphine if available) if there is ongoing pain or distress in younger children. dysphagia has been noted to be associated with retrosternal chest pain in adults, and should be managed in children with management of bleeding can include transfusion of packed red cells or components (e.g. fresh frozen plasma if required), and particularly for malnourished children supplementation of vitamin k (enterally or parentrally) should be considered. however evidence is limited, particularly as regards antifibrinolytics [ ] . other empirical management for shortnesss of breath (oxygen via nasal cannulae if available); seizures (glucose if hypoglycaemic or monitoring unavailable and benzodiazepines); confusion (reassurance, possibly sedation if agitation severe) should be given as needed/available depending on context. in the unfamiliar and frightening environment of the treatment centre, reassurance from staff or other caregivers cannot be overemphasised as a crucial therapeutic intervention. given the gastrointestinal symptoms of evd and the background prevalence of malnutrition in the countries evd has affected, assessment for malnutrition at admission is advisable. who guidelines are that a mid-upper arm circumference (muac) should be checked and oedema assessed for at a minimum if it not feasible to assess anthropometry in more detail [ ] . as weight of children is key both in assessing hydration and nutritional status, we would suggest checking weight on admission in addition to muac and presence/absence of oedema. as above, scales could be kept within a ziplock plastic bag to protect from high concentration chlorine and ease of decontamination after use. if severe acute malnutrition is present, fluid resuscitation should be given according to who guidelines using smaller volumes and resomal™ as opposed to standard oral rehydration salts [ ] . for asymptomatic breastfed infants whose mother is unwell with evd, current recommendations based on available evidence are to separate the mother and infant and use replacement ready to use infant formula [ , ] . if the infant also has signs/ symptoms of evd, or a confirmed diagnosis, the current guidelines are that the benefits of continuing breastfeeding are likely to outweigh the risks and so breastfeeding should be continued if the mother is well enough to do so [ ] . the challenges of caring for unwell, frightened children within a "red zone" have been well documented during the west african outbreak [ , , , , ] . this problem is amplified as many children were admitted unaccompanied by a caregiver (up to % in one study [ ] ), either because family members had already succumbed to disease or because fear of nosocomial infection prevented either relatives from wishing to enter the "red zone" or unit policies forbade the admission of asymptomatic caregivers. apart from the risk of nosocomial infection between suspect evd patients posed by unaccompanied children (who were difficult to keep in their allocated bed space); there were also the hazards of sharps bins and high concentration chlorine within the red zone. units developed different practices to mitigate these risks. one treatment centre had a nursing round specifically dedicated to paediatric care times a day, to manage intravenous infusions and ensure that unaccompanied small children were fed times daily with therapeutic milk [ ] . other units started to develop protocols to employ survivors (believed to be at low risk of re-infection with evd) to care for unaccompanied children, but none, to our knowledge put the protocols into practice before the end of the west african outbreak. the possibility of either dedicated paediatric clinicians or a specific paediatric area with risks e.g. sharps and chlorine buckets minimised have both been discussed, and were put into limited practice towards the end of the west african outbreak. one study collected data post-discharge from caregivers admitted to ebola holding units with children who subsequently tested negative for evd [ ] . it was possible to contact approximately % of caregivers admitted, and of those contacted, none were subsequently readmitted with evd. for the overwhelming majority of those who it was not possible to contact, this was due to a lack of contact details. this indicates that it may not be as dangerous as anticipated to admit asymptomatic caregivers with their children, although this should be done in the context of very clear instructions about hand hygiene and strict isolation between patients. in the event that admitting caregivers with children is not possible or not felt to be safe, alternative mechanisms for managing the pastoral care needs of children have included using stretches of clear plastic sheeting between "red" and "green" zones to enable frequent communication with staff/relatives outside with children inside (heldermann t., personal communication); 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cord- -g ndggwc authors: sood, lakshay; sood, vanita title: being african american and rural: a double jeopardy from covid‐ date: - - journal: j rural health doi: . /jrh. sha: doc_id: cord_uid: g ndggwc nan the effect of covid- on african americans is better understood by analyzing the racial disparities related to previous pandemics caused by other types of coronaviruses. results from all the different studies of the spanish influenza pandemic indicate that african americans had higher mortality and case fatality rates than whites. during the h n influenza a pandemic, african americans had the highest overall susceptibility to complications arising from the infection, followed by whites and hispanics. rural states like oklahoma documented highest hospitalization rates for african americans and lowest for whites. these data are comparable to those for covid- , where % of hospitalized patients nationwide (among those whose race was known) were african american, even though the latter constitute only % of the us population. why are african americans at greater risk for covid- , as compared to other racial/ethnic groups? there are possible explanations: ) social determinants of health; ) comorbidities and coexposures; and ) genetic differences. furthermore, why may rural african americans be at even greater risk than urban african americans? this health inequity is largely attributable to social determinants of health. the who defines social determinants of health as "the conditions in which people are born, grow, live, work, and age. these circumstances are shaped by the distribution of money, power, and resources at global, national and local levels. with lower median incomes for rural than urban african american households. although data for covid- are not known, previous analyses indicate that influenza-related hospitalization was higher for persons residing in census tracts with a greater level of poverty. many african americans reside in small and/or multi-generational homes with extended families, use public transportation to commute to jobs and other places, and many of them are "essential" workers (like janitors and delivery workers), which means face-toface contact with many people (often without adequate personal protective equipment). this makes social distancing and self-isolation virtually impossible, and it increases the risk of exposure to sars-cov- . the southeast, which has the highest concentration of african americans in the country, has more cash-poor adults without health care coverage when compared to other regions. within this region, there are racial disparities in health care coverage that disproportionately affect african americans. this implies that african americans in the southeast are less likely to afford covid- screening tests and treatments than other populations nationwide. given that about a quarter of rural hospitals may shut down due to the covid- pandemic, , mostly in the southeast and lower great plains, rural african americans will have difficulty accessing preventive and therapeutic services. many african americans do not have access to a primary care provider. without a primary care provider, they are more likely to fall victim to misinformation about covid- , unnecessarily use emergency rooms, or use them too late. in new york city, african americans without providers could not receive covid- -related help even from the city's non-emergency line, which was overwhelmed during the outbreak. african americans, particularly in the rural southeast, are often suspicious of the health system, with a legacy of abuses such as the - tuskegee syphilis study in rural alabama, in which exclusively african american participants were allowed to die untreated. unfortunately, the us health system has been shown repeatedly to offer inferior care to african americans with the same conditions and insurance as white patients, indicating a subconscious racial bias in health care. as compared to whites, african americans consume less fruits and vegetables and engage in less exercise. these lifestyle disparities, rooted in unequal access to economic and social resources, are even more pronounced for rural african americans. , although dietary risk factors for covid- are not understood, frequent intake of fruits and vegetables protects against influenza-like illnesses, and regular and moderate exercise protects against influenza-related cardiorespiratory mortality. the likelihood of having obesity, diabetes, hypertension, and cardiovascular disease is higher for african americans than for whites. [ ] [ ] [ ] [ ] these diseases are also established risk factors for covid- prevalence and mortality. , further, as compared to non-rural communities, rural communities may have a greater prevalence of these conditions. [ ] [ ] [ ] for example, rural african american heart disease mortality is among the highest ever recorded anywhere in the world. these comorbidities are associated with high levels of inflammatory cytokines, which may contribute to the increased morbidity and mortality in covid- . based on a national survey, . % of african american men smoke, as compared to . % of white men. smokers have increased levels of angiotensin converting enzyme ii (ace ) receptors in their airway epithelia, which is the entry receptor for sars-cov- , making smokers more susceptible to covid- . consistent with this information, smokers are . times more likely to have severe symptoms of covid- and approximately . times more likely to be admitted to an icu, need mechanical ventilation, or die, as compared to non-smokers. based on a - national survey, marijuana use disorder is greatest among african americans compared to other races/ethnicities. although not proven, it is possible that marijuana use may affect the ace receptor like cigarette smoke, predisposing users to census tracts with a higher percentage of african american population have higher levels of outdoor air pollution. small particulate matter of less than . microns in aerodynamic diameter, also known as pm . , are particularly associated with adverse health outcomes. in a nationwide study using data from , counties in the us, an increase of only g/m in pm . was associated with a % increase in the covid- death rate, suggesting that long-term exposure to air pollution, particularly in african american communities, increases their vulnerability to experiencing severe covid- outcomes. although the genetic predisposition to covid- has not been specifically studied, there is limited evidence to suggest that genetic differences underlie the racial susceptibility to viral infections. a recent study, mapping the expression quantitative trait loci (eqtls), demonstrates that there is extensive variation in transcriptional responses to immune challenges between individuals of african and european descent. the strongest difference in transcriptional response is observed for genes with antiviral and inflammatory-related functions. in an in vitro study using macrophages, many of the genes showing european versus african ancestry-related transcriptional differences in isoform usage were in fact key regulators of innate immunity. one such gene included the oas gene that encodes the rural african americans and this article is protected by copyright. all rights reserved. isoforms with varying enzymatic activity against viral infections. this limited data may help explain the genetic basis to the predisposition to viral infections in african americans. the primary goal of the pandemic containment in rural african american communities is to reduce the sars-cov- virus transmission. coronavirus was slow to spread to rural america. not anymore covid- : black people and other minorities are hardest hit in us racial disparities in louisiana's covid- death rate reflect systemic problems the coronavirus is infecting and killing black americans at an alarmingly high rate race and influenza pandemic in the united states: a review of the literature racial disparities in exposure, susceptibility, and access to health care in the us h n influenza pandemic world health organization. social determinants of health economic policy institute. the state of working america, th edition comparison of rural and urban america: household income and poverty influenza-related hospitalizations and poverty levels -united states the coverage gap: uninsured poor adults in states that do not expand medicaid a surge of coronavirus patients could stretch hospital resources in your area in rural hospitals are at risk of closure and the problem is getting worse racial disparities in geographic access to primary care in philadelphia caring for miners during the coronavirus disease- (covid- ) pandemic. j rural health how to save black and hispanic lives in a pandemic perception of racial barriers to health care in the rural south african americans' views on research and the tuskegee syphilis study racial/ethnic disparities in exercise and dietary behaviors of middle-aged and older adults cardiovascular disease among women residing in rural america: epidemiology, explanations, and challenges considering intersections of race and gender in interventions that address us men's health disparities various factors associated with the manifestation of influenza-like illness effect of lifestyle factors on risk of mortality associated with influenza in elderly people disparities in diabetes: the nexus of race, poverty, and place racial disparities in cardiovascular disease risk: mechanisms of vascular dysfunction racial differences in hypertension: implications for high blood pressure management. the american journal of the medical sciences exploring racial disparity in obesity: a mediation analysis considering geo-coded environmental factors covid- : risk factors for severe disease and death risk factors for severity and mortality in adult covid- inpatients in wuhan united states department of health and human services. cdc newsroom. rural americans at higher risk of death from five leading causes urban-rural differences in coronary heart disease mortality in the united states the determinants of activity and specificity in actinorhodin type ii polyketide ketoreductase obesity and its implications for covid- mortality. obesity (silver spring) american lung association. tobacco use in racial and ethnic populations ace- expression in the small airway epithelia of smokers and copd patients: implications for covid- . the european respiratory journal covid- and smoking: a systematic review of the evidence race/ethnicity differences between alcohol, marijuana, and co-occurring alcohol and marijuana use disorders and their association with public health and social problems using a national sample cannabis-related illness in missouri emergency room racial, ethnic, and income disparities in air pollution: a study of excess emissions in texas exposure to air pollution and covid- mortality in the united states genetic adaptation and neandertal admixture shaped the immune system of human populations genetic ancestry and natural selection drive population differences in immune responses to pathogens a commentary on rural-urban disparities in covid- testing rates per , and risk factors why coronavirus could hit rural areas harder covid- and health care's digital revolution too important to ignore: leveraging digital technology to improve chronic illness management among black men key: cord- -t wkv b authors: treadwell, henrie m. title: the pandemic, racism, and health disparities among african american men date: - - journal: am j mens health doi: . / sha: doc_id: cord_uid: t wkv b nan the coronavirus pandemic has amplified health disparities by race and gender, perhaps most notably among african american men. surveillance data reveal that males are disproportionately affected by covid- , and that black populations are disproportionately affected overall (wortham et al., ) . it cannot and should not be a surprise that populations who are subject to poverty, fragile housing, food and fiscal insecurity, no or inadequate health insurance are disproportionately affected by . it is axiomatic that populations that have disproportionate rates of health conditions such as hypertension, diabetes mellitus, obesity, and cardiovascular disease are more susceptible to both contracting coronavirus and to adverse outcomes. the criminal justice system interjects an additional risk factor given that those captured in this matrix are predominantly african american males. the impact of covid- across jails, prisons, and detention centers may never be fully reported out to the community. what recent data exist are grim. in those facilities where testing has occurred, the positive test rate is % among the incarcerated and extremely high levels of positive tests (dolovich, ) . positively, the prospective heroes act (section ) would allow medicaid to cover health services in the last days pre-release. still once released, major barriers to basic and critical health and human services still exist as three quarters of reentry service providers have scaled back or have closed their services (csg justice center staff, ). the lack of support services hinders opportunities for individuals to successfully reunite with families, attain employment, and address burgeoning child support and other restorative justice costs. grappling with the disparities revealed by the pandemic requires an examination and actions to ameliorate racial discrimination that has had an impact for years. african american boys and men have experienced poor health and health outcomes historically, and little or nothing has changed over the years though improvements in u.s. health services and systems are reportedly the most advanced in the world. the - coronavirus pandemic amplifies the existing injustices. while some attribute the overall poor health and disparate rates of morbidity and mortality to individual behaviors, that assessment fails to assess the direct damage inflicted by a social and political system that has marginalized and minimized efforts to provide meaningful services even at the primary health-care level. the compendium of injuries experienced that circumscribe well-being are described as the social determinants of health. significantly, a more nuanced expression on the how the collateral damage is delivered are described as the political determinants of health. in sum, policies that do not incorporate potential for fostering racial disparities are the drivers of disease, health inequities, and the unequal burden of morbidity and mortality experienced by communities of color. examination of current health-care system policies, practices, and experiences is an inadequate starting point for a discussion of redressing health disparities. rather, historical perspectives are important to understand the depth of destruction caused by hundreds of years of exclusion from justice. it is not possible to thoroughly understand why health inequities exist without acknowledging the terrible cumulative penalty that is being paid as a result of intentionally exclusionary policy that based solely on skin color, race, ethnicity, and gender. social practices and political policies have discriminated against black men since the black codes (history.com, ), the man in the house rule (moffitt et al., ) which excluded them from the home lest funding for children be lost, and the exclusion from social security (dewitt, ). a racebased policy and the continuing overwhelming exclusion of boys and men over the age of from medicaid (hinton & artiga, ) fosters exclusion that could have been mitigated if states had expanded medicaid under the affordable care act. in sum, the nation's policymakers have designed a system that discriminates and until now legislators appear loath to enact policies and programs to insure health equity for all. major systemic barriers have been erected that affect morbidity and mortality in the african american community. the lack of insurance, lack of a living wage, and employment in low-wage professions that do not provide sick leave and require that individuals go to their "essential jobs" (e.g. meat packing plants, home health care, as nurses' aides or janitorial staff, among others) despite their health symptoms or status, elevate mortality in poor communities of color. the distinction that must be made is that african american men are not disproportionately and prematurely dying simply because they are african american men. there is no evidence that the cause of the disparity is embedded in the genes. they are dying because they do not have a healthcare home as a result of not having income to pay for the visits. further and perhaps even more damaging throughout the pandemic are health messages supported by federal government leaders that insist that individuals not go to the clinic or emergency room. rather they are instructed to call their doctor. the cloak of invisibility is firmly wrapped around the population of those, mainly men of color, who have no doctor (treadwell & ro, ) . what are they to do and why is their plight ignored? a striking conundrum is that data are not consistently collected by race and gender making it impossible to identify population-based service deficiencies that guide the design of specific strategies, appropriate tactics, and barrier-free interventions. it is important to acknowledge that institutionalized populations are not included in population statistics unless they enter the health-care system for treatment, a subject discussed at length in the recently published manuscript, "discerning disparities: the data gap" (treadwell et al., ) and in the article "collecting demographic data is the first step in eliminating racism in healthcare" (eschner, ) . damage is perpetrated when researchers and individuals who report on morbidity, mortality, and equitable health-care access remain silent about institutionalized populations, such as african american men who are disproportionately represented in america's prisons. the silence from epidemiologists and others charged with profiling the heath care of the nation is perplexing as it allows racist and exclusionary practices to continue unabated and the public, that might respond affirmatively, to remain ignorant of the depth of health inequities linked to race and gender alone. african american men are subject to injustices on so many levels. those entities and organizations that "police" the health-care system through their incomplete data collection and reporting out strategies are failing the public, too, along with their failure to advocate for inclusive data collection. to be sure, the issues do not solely affect african american men. yet each group (e.g. hispanics, pacific islanders, and native americans) has a unique path in the united states and each group should be examined so that comparative analyses can be conducted to determine similarities that can be enacted to meet their needs, along with strategies that respond to each racial group and their heterogeneous historical and contemporary experiences. we as a nation did not come to this place by chance. race and racism have been the catalysts. the inflection point is here. the time to act to redress inequities and support health justice is now. to achieve the change that we need to see in our society, we must advocate for expanded medicaid and/or health-care coverage for all in the nation. equally important, systems must be designed to ensure that behavioral and oral health care are an integrated part of primary care. we must also address the fact that a disproportionate number of african american men are incarcerated and foster integration of data from those in the community and those incarcerated to develop a complete portrait of health status of these individuals and establish interventions that reflect the totality of need. these men do come home eventually, and their health service needs must be anticipated and accommodated, something not possible now because of parallel data systems. finally, it is important to begin the process of holding dedicated days in community clinics that invite boys and men so that their total health care and conditions, not just their prostate health, can be assessed and treated, as appropriate. and, we must expand those that research health access and analysis to include anthropologists and others in the social sciences to enable accurate delineation and enumeration of the issues, illumination of the pathways to reducing invisibility, and establishment as bedrock a rational, humane, equitable, and gender inclusive health-care system. the time to act is now. failure to act is an act that promulgates the current inequities. henrie m. treadwell https://orcid.org/ - - - survey shows reentry services halting across u the decision to exclude agricultural and domestic workers from the social security act ucla law covid- behind bars data project collecting missing demographic data is the first step to fighting racism in healthcare characteristics-of-remaining-uninsured-men-and-potentialstrategies-to-reach-and-enroll-them-in-health-coverage/ history state afdc rules regarding the treatment of cohabitors poverty, race, and the invisible men discerning disparities: the data gap characteristics of persons who died with covid- -united states key: cord- -f rbn x authors: alkhatib, ala l.; kreniske, jonah; zifodya, jerry s.; fonseca, vivian; tahboub, mohammad; khatib, joanna; denson, joshua l.; lasky, joseph a.; lefante, john j.; bojanowski, christine m. title: bmi is associated with coronavirus disease intensive care unit admission in african americans date: - - journal: obesity (silver spring) doi: . /oby. sha: doc_id: cord_uid: f rbn x objective: coronavirus disease (covid‐ ) has disproportionately impacted the african american community. this study aims to identify the risk factors for severe covid‐ disease in african american patients. methods: this was a retrospective cross‐sectional analysis of african american patients with covid‐ treated between march and april , , at a single tertiary center. the primary outcome of interest was severe disease defined as those requiring intensive care unit (icu) admission. results: the study included consecutive patients. the mean age was years, and % were women. the mean (sd) of bmi was . ( . ) kg/m( ). overall, patients admitted to the icu were older ( vs. years, p = . ) and had higher bmi ( . kg/m( ) vs. . kg/m( ), p = . ). in unadjusted and adjusted analysis, the factors most associated with icu admission in this sample were age (adjusted odds ratio [aor]: . ; % ci: . ‐ . ), bmi (aor: . ; % ci: . ‐ . ), and lung disease (aor: . ; % ci: . ‐ . ). conclusions: this study identified risk factors for severe disease in covid‐ , specifically in an african american population. further inclusive research aimed at optimizing clinical care relevant to the african american population is critical to ensure an equitable response to covid‐ . by january , , the novel severe acute respiratory syndrome coronavirus was identified as the cause for an outbreak in china due to what is now called coronavirus disease (covid- ). on march , , the world health organization declared the covid- outbreak a global pandemic ( ) . the severity and clinical presentation of covid- are widely variable, ranging from asymptomatic or mild disease in the majority of cases to severe respiratory failure and dysregulated inflammatory responses in a minority of patients. age and certain comorbidities, such as hypertension and diabetes, have been well identified as risk factors for the development of severe disease ( ) ( ) ( ) . obesity is also emerging as a likely risk factor for severe disease development ( ) ( ) ( ) . the covid- epidemic in the united states tracks along well-documented and historical health disparities, with early data suggesting disproportionate morbidity and ► there is a wide clinical spectrum of disease in coronavirus disease (covid- ), ranging from asymptomatic and mild cases to profound critical illness and respiratory failure. ► age and specific comorbidities such as hypertension and diabetes mellitus have been identified as independent risk factors for severe covid- . what does this study add? ► major health disparities have been identified in the covid- epidemic within the united states, and this is one of the first studies to focus specifically on the risk factors within an african american population, a community that has been disproportionately impacted by this disease. ► in addition to age, obstructive lung disease, and hypertension, this study adds further evidence supporting the association between bmi and disease severity in covid- . how might these results change the direction of research or focus of clinical practice? ► current centers for disease control and prevention recommendations describe individuals with bmi > as being at "high risk" for severe illness in covid- , whereas our results suggest that a lower threshold should be considered for this high-risk category in covid- . ► this study calls for further mechanistic studies aimed at understanding the association observed between obesity and the severity of respiratory disease and the inflammatory response. see commentary, pg. x. mortality within the african american community ( , ) . despite this, there is a relative dearth of analysis relevant to the african american experience. in louisiana, % of covid- -related deaths have occurred among black persons, who represent . % of the state's population ( , ) . new orleans, a predominantly african american city, has experienced among the most severe outbreaks of covid- in the united states. in this study, we aim to describe the baseline characteristics of laboratoryconfirmed covid- -positive african american patients and determine the possible risk factors, including bmi, for the development of severe disease and admission to the intensive care unit (icu). this is a single-center retrospective cross-sectional study of all consecutive, self-reported african american patients confirmed to have covid- who presented to a tertiary academic hospital between march and april , . patients were identified through reported positive laboratory test results during this specified time period, and individual patient data were obtained through retrospective electronic medical record review by members of the investigatory team. this study was reviewed and approved by the tulane university biomedical institutional review board and was granted a waiver of consent. the primary outcome of this study was severe disease, defined here as those patients requiring icu admission for covid- -related complications. in our study, this aligned closely with respiratory failure requiring mechanical ventilation. individuals with nonsevere disease were defined as patients who presented to the emergency department or who were admitted to the hospital and successfully discharged home without need for further escalation of care. patients with missing data or pending covid- -confirmatory testing were excluded from the study. several covariates of interest were collected, including age, sex, bmi reported in kilograms per meter squared as calculated on admission through measurements of both weight and height, and the comorbidities diabetes mellitus (dm), hypertension, chronic kidney disease (ckd), congestive heart failure, and obstructive lung disease (including both chronic obstructive pulmonary disease and asthma). comorbidities were identified if the patient had a medical record with an established diagnosis, was on medications known to treat these comorbidities, or had previously reported laboratory values, such as an estimated glomerular filtration rate < to define ckd. means and sd were calculated for age and bmi separately for non-icu and icu cases, and two-sample t tests were used to test for significant differences in these means. categorical patient characteristics were summarized with counts and percentages. pearson χ tests were used to test for significant percentages among the non-icu and icu cases. multivariable logistic regression analysis was performed to examine the association between bmi and critical illness in patients with covid- , adjusting for the potential effects of the covariates of age, sex, dm, hypertension, congestive heart failure, ckd, and obstructive lung disease (both chronic obstructive pulmonary disease and asthma). results were presented as odds ratios (or) with % cis and p values. data were statistically analyzed using sas software version . (sas institute inc., cary, north carolina). of the screened consecutive patients with positive covid- test results, were african american and were enrolled in our study. the mean age was , and % were women. the mean (sd) bmi was . ( . ). characteristics of the study population based on the disease severity are presented in table . eighty-five percent of the severe cases admitted to the icu had respiratory failure requiring intubation and mechanical ventilation. icu mortality for severe cases was %; however, . % of the patients were still intubated and requiring mechanical ventilation at the time of analysis, which may impact and potentially increase this percentage. patients with severe disease requiring icu admission were older ( vs. years, p = . ) and had higher bmi ( . vs. . , p = . ). the prevalence of dm and ckd was also significantly higher in patients with severe disease (p values of . and . , respectively). thirty-nine of the forty-six patients admitted to the icu during this study period were in respiratory failure requiring mechanical ventilation. an additional two patients required high-flow nasal canula, and an additional three patients required the use of a nonrebreather mask. on the basis of the available data, the average ratio of the partial pressure of oxygen to the fraction of inspired oxygen of patients admitted to the icu was . (n = ), which is consistent with moderate acute respiratory distress syndrome; the average admission lactate dehydrogenase level was . (n = ); the average admission ferritin level was , . (n = ); and the average high-sensitivity c-reactive protein level was . (n = ). in adjusted analysis, hypertension, age, bmi, and obstructive lung disease are independent risk factors for severe disease in adjusted analysis ( in this retrospective observational cross-sectional study, we found that age, higher bmi, and obstructive lung disease were associated with severe covid- in an african american population. these results were unchanged after adjusting our analysis for age, sex, and underlying comorbidities. obesity www.obesityjournal.org obesity | volume | number | month brief cutting edge report in early studies of the international experience, obesity was not evaluated as an independent risk factor for critical illness; however, recent analyses regarding the covid- pandemic in europe and the united states suggest that obesity is highly prevalent among patients suffering from severe covid- ( - , ). as a recognized independent risk factor for severe respiratory illness in viral pneumonias such as h n ( ) , special attention to the needs of patients with obesity is urgently needed as the covid- pandemic spreads to communities with a high prevalence of obesity. current centers for disease control and prevention recommendations describe individuals with bmi > as being at "high risk" for severe covid- illness, whereas our results suggest that a lower threshold should be considered for this high-risk category. a significant knowledge gap remains regarding the mechanisms underlying the association between viral respiratory disease severity and the cluster of illnesses that define metabolic syndrome. a severe inflammatory cytokine response appears to be the hallmark of severe covid- . to this point, obesity is associated with low-grade inflammation associated with insulin resistance and diabetes and therefore may lead to the amplification of the inflammatory response to infection ( ) . further studies looking into the mechanisms behind these observations are ongoing. a recently published report from the centers for disease control and prevention showed that a third of hospitalized patients with covid- in the united states were african american ( ), evidencing a disproportionate impact on the african american community. further inclusive research toward optimizing clinical care relevant to the african american population is critical to ensuring an equitable response to covid- . previous studies have identified obesity as a risk factor for severe disease in several populations ( ) ( ) ( ) . our analysis confirmed that obesity is a significant determinant of disease severity in an african american population. these data further support the utility of bmi in the identification of patients at high risk of severe covid- . appropriate management of obesity and the associated comorbidities of metabolic syndrome, as well as of the social determinants of health that underlie these conditions, is therefore critical to addressing the evolving covid- crisis.o funding agencies: this work was supported by a grant from the louisiana clinical and translational science center (u gm to cmb). disclosure: the authors declared no conflict of interest. clinical course and risk factors for mortality of adult inpatients with covid- in wuhan, china: a retrospective cohort study covid- in critically ill patients in the seattle region -case series critical care utilization for the covid- outbreak in lombardy, italy: early experience and forecast during an emergency response obesity in patients younger than years is a risk factor for covid- hospital admission high prevalence of obesity in severe acute respiratory syndrome coronavirus- (sars-cov- ) requiring invasive mechanical ventilation obesity is a risk factor for greater covid- severity covid- and african americans assessing differential impacts of covid- on black communities louisiana department of health. coronavirus (covid- ) epidemiology of covid- in a long-term care facility in king county, washington factors associated with death or hospitalization due to pandemic influenza a (h n ) infection in california inflammation and emerging risk factors in diabetes and atherosclerosis hospitalization rates and characteristics of patients hospitalized with laboratory-confirmed coronavirus disease -covid-net key: cord- -o y rn z authors: ng, melinda; ndungo, esther; kaczmarek, maria e; herbert, andrew s; binger, tabea; kuehne, ana i; jangra, rohit k; hawkins, john a; gifford, robert j; biswas, rohan; demogines, ann; james, rebekah m; yu, meng; brummelkamp, thijn r; drosten, christian; wang, lin-fa; kuhn, jens h; müller, marcel a; dye, john m; sawyer, sara l; chandran, kartik title: filovirus receptor npc contributes to species-specific patterns of ebolavirus susceptibility in bats date: - - journal: elife doi: . /elife. sha: doc_id: cord_uid: o y rn z biological factors that influence the host range and spillover of ebola virus (ebov) and other filoviruses remain enigmatic. while filoviruses infect diverse mammalian cell lines, we report that cells from african straw-colored fruit bats (eidolon helvum) are refractory to ebov infection. this could be explained by a single amino acid change in the filovirus receptor, npc , which greatly reduces the affinity of ebov-npc interaction. we found signatures of positive selection in bat npc concentrated at the virus-receptor interface, with the strongest signal at the same residue that controls ebov infection in eidolon helvum cells. our work identifies npc as a genetic determinant of filovirus susceptibility in bats, and suggests that some npc variations reflect host adaptations to reduce filovirus replication and virulence. a single viral mutation afforded escape from receptor control, revealing a pathway for compensatory viral evolution and a potential avenue for expansion of filovirus host range in nature. doi: http://dx.doi.org/ . /elife. . ebola virus (ebov) and some of its relatives in the family filoviridae (filoviruses) cause sporadic outbreaks of a highly lethal disease. these outbreaks are thought to be initiated by viral spillover from an animal reservoir to a highly susceptible accidental host, such as a human or nonhuman primate (feldmann and geisbert, ; leroy et al., ; towner et al., ) . recent work suggests that some filoviruses infect bats in nature, and that these viruses may be distributed more widely than previously recognized. very short rna fragments corresponding to portions of ebolavirus genomes were detected in several frugivorous bats of the family pteropodidae ('old world fruit bats') in both africa and asia (leroy et al., ; jayme et al., ) , and longer filovirus rna fragments and near-complete rna genomes were isolated from insectivorous schreibers's long-fingered bats in asia and europe, respectively (negredo et al., ; he et al., ) . however, despite considerable efforts, infectious ebolaviruses have never been recovered from bats. by contrast, marburg (marv) and ravn (ravv) viruses were found to circulate in egyptian rousettes (rousettus aegyptiacus), indicating that these bats are susceptible to marv/ravv and encounter them frequently in nature. egyptian rousettes have been proposed as natural hosts for these viruses (amman et al., ; towner et al., ) . this progress notwithstanding, many key questions remain. for example, the biological factors that influence filovirus host range and interspecies transmission are still poorly understood, as are the virus-host relationships that determine which species of bats are susceptible to infection by ebov and other filoviruses. viral entry receptors are key determinants of tissue tropism and host range (radoshitzky et al., ; sheahan et al., ; hueffer et al., ; demogines et al., ) . niemann-pick c (npc ), a highly conserved endo/lysosomal protein involved in cellular cholesterol trafficking, was recently identified to be an essential entry receptor for all known filoviruses (cô té et al., ; carette et al., ; ng et al., ) . in this study, we uncover a pattern of virus and host species specificity in the filovirus susceptibility of bat cells, which can be explained by elife digest ebola virus and other filoviruses can cause devastating diseases in humans and other apes. numerous small outbreaks of ebola virus disease have occurred in africa over the past years. however, in - , the largest outbreak on record took place in three western african nations with no previous history of the disease. human outbreaks of ebola virus disease likely begin when a person encounters an infected wild animal. though it remains unclear precisely which animals harbor ebola virus between outbreaks, and how they transmit the virus to humans or other primates, recent work showed that some filoviruses do infect specific types of bats in nature. ng, ndungo, kaczmarek et al. sought to identify the genes that influence whether or not a type of bat is susceptible to infection by ebola virus and other filoviruses. several filoviruses, including ebola virus, were tested to see if they could infect cells that had been collected from four types of african fruit bats. these bats are all found in areas where outbreaks have occurred in the past. the tests revealed that a small change in the sequence of the npc gene in some bat cells greatly reduced their susceptibility to ebola virus. npc encodes a protein that mammals need in order to move cholesterol within their cells. in humans, the loss of the protein encoded by npc causes a rare but very severe disease called niemann-pick type c disease. this protein also turns out to be a receptor that the filoviruses must bind to before they can infect the cells. further analysis then revealed that npc has evolved rapidly in bats, with changes concentrated in the parts of the receptor that interact with ebola virus. ng, ndungo, kaczmarek et al. went on to discover some changes in the genome sequence of ebola virus that could compensate for the changes in the bat's npc gene. these findings hint at one way that a filovirus could evolve to better infect a host with receptors that were less than optimal. following on from this work, the next challenges will be to expand the investigation to include additional types of bats, other types of mammals, and other host genes that could influence filovirus infection and disease. further studies could also examine the other side of the arms race -that is, the evolution of viral genes in bats. however, such studies would be complicated by the lack of viral sequences that have been collected from bats, because to date most have been isolated from humans and other primates instead. changes in the affinity of the essential interaction between npc and the filovirus entry glycoprotein, gp. crucially, genetic analyses reveal that npc is under positive selection in bats, with a strong signature of selection at precisely the same residue that influences the filovirus-receptor interaction. our findings suggest that amino acid sequence changes in npc at these positively-selected sites represent host adaptations to resist filovirus infection, and reveal one pathway by which a filovirus could escape from receptor control. in sum, our results support the hypothesis that bats and filoviruses have been engaged in a long-term co-evolutionary relationship, one facet of which is a molecular arms race between the viral glycoprotein and its entry receptor, npc . means ± sd (n = - ) from two biological replicates are shown. in panels c and d, the infectivity of each virus was normalized to that obtained in vero grivet monkey cells. means for infection of the different cell lines by each virus were compared by one-way anova (p-value indicated above each group of bars). tukey's post hoc test was used to compare infection means on hypsignathus monstrosus vs eidolon helvum cells (*p < . ; ****p < . ; ns, no statistical significance). doi: . /elife. . the following figure supplements are available for figure : we first explored the possibility that there exist virus-and/or bat species-dependent differences in the cellular host range of filoviruses. kidney fibroblast cell lines derived from three african pteropodids whose ranges overlap the locations of known african filovirus disease outbreaks ( figure a ,b) were exposed to authentic ebov and marv ( figure c ). we observed a large ebov infection defect in african straw-colored fruit bat (eidolon helvum) cells but not in cells from bü ttikofer's epauletted fruit bats (epomops buettikoferi) and egyptian rousettes. by contrast, cells from bats of all three species were similarly susceptible to infection by marv ( figure c) . thus, cells from african straw-colored fruit bats appear to be selectively refractory to ebov infection. an npc -dependent block to cell entry accounts for the ebov infection deficit in african straw-colored fruit bat cells the viral spike glycoprotein, gp , (herein termed gp) mediates all steps of filovirus entry into the cytoplasm of host cells . vesicular stomatitis viruses bearing filovirus gp proteins (vsv pseudotypes) provide a highly validated surrogate system to recapitulate filovirus entry under biosafety level containment (takada et al., ; jangra et al., ) . to assess whether the ebov infection defect in the african straw-colored fruit bat cells occurs at the viral entry step, we exposed an expanded panel of kidney fibroblast cell lines from four african pteropodids to vsv pseudotypes bearing gp spikes (vsv-gp) from seven filoviruses, including two non-african viruses, reston virus (restv) and lloviu virus (llov) ( figure d ). as observed with authentic ebov, vsv-ebov gp infection was substantially reduced in the african straw-colored fruit bat cells; however, this virus could efficiently infect cells derived from the other pteropodids, including those of a proposed ebov host, the hammer-headed fruit bat (hypsignathus monstrosus) (leroy et al., ) . strikingly, only vsvs bearing ebov gp, and to a lesser degree, those bearing bdbv and tafv gp, were deficient at infecting african straw-colored fruit bat fibroblasts. similar strong but ebov-specific reductions in infection were measured in two kidney and lung cell lines derived from additional african straw-colored fruit bats (figure -figure supplement ) . therefore, reduced infection of these bat cells by ebov reflects a virus-and host species-specific restriction at the cell entry step. we surmised that the filovirus receptor, npc , might explain the selective resistance of the african straw-colored fruit bat cells to ebov entry and infection. accordingly, we engineered these cells to stably express human npc (hsnpc ) (figure -figure supplements , ), and then exposed them to ebov ( figure a ). provision of hsnpc substantially enhanced authentic ebov infection in the african straw-colored fruit bat cells. by contrast, we found no evidence that either marv infection in these cells, or ebov/marv infection in permissive bü ttikofer's epauletted fruit bat cells was limited by receptor availability (figure a ). finally, similar results were obtained with vsvs bearing filovirus glycoproteins ( figure b ). taken together, these findings indicate that ebov infection is reduced in african straw-colored fruit bat cells because of a specific molecular incompatibility between the ebov glycoprotein and the filovirus entry receptor. npc -dependent cell entry is reduced, but not completely eliminated, in african straw-colored fruit bat cells although ebov entry and infection in african straw-colored fruit bat cells was consistently reduced to . - % relative to that in cells from the other pteropodids, we noted that infection was not completely blocked. to determine if ebov could inefficiently infect these bat cells via an npc -independent mechanism, we used crispr/cas genome engineering to derive an african straw-colored fruit bat cell line fully deficient in npc . we identified a single cell clone (eidolon helvum npc -# [ehnpc -# ]) in which all npc alleles bore insertions or deletions (indels) at the expected site ( figure a ). these indels were predicted to frameshift the npc open reading frame at amino acid position (homo sapiens hsnpc numbering), generating truncated polypeptides of , , and residues that lacked the majority of the -amino acid npc sequence. ehnpc -# cells were deficient in clearance of lysosomal cholesterol, a well-established cellular function of npc (carstea et al., ) , but could be rescued by ectopic hsnpc expression, confirming that npc had indeed been disrupted in these cells ( figure b ). we next exposed wild-type (wt) and ehnpc -# fibroblasts to vsvs bearing ebov or marv gp. no detectable infection was obtained with either virus in npc -deficient cells, indicating that filovirus entry into these cells is absolutely dependent on the e. helvum npc ortholog ( figure c ). moreover, ebov gp-dependent infection in ehnpc -# cells reconstituted with hsnpc was dramatically enhanced over that observed in wt cells, whereas marv gp-dependent infection was rescued by hsnpc expression to a level resembling that in wt cells ( figure c ). therefore, the low levels of ebov infection in african straw-colored fruit bat cells likely arise from the weak, but nonzero, activity of ehnpc as an ebov entry receptor. filovirus gps must directly engage the second luminal domain of npc , domain c, during cell entry . accordingly, we postulated that the african straw-colored fruit bat npc ortholog is poorly recognized by ebov gp. to test that hypothesis, we generated and sequenced npc cdnas from all four pteropodid cell lines. alignment of their domain c amino acid sequences with that of hsnpc revealed a high degree of conservation (> %), with identical arrangements of cysteine residues and similar predicted secondary structures suggestive of a similar overall fold (figure -figure supplement ) . to examine gp-npc binding, we engineered and expressed soluble forms of the four pteropodid npc domain cs, as described for hsnpc (figure -figure supplement ) . a cleaved form of ebov gp could capture hsnpc domain c in an elisa, as shown previously . ebov gp bound with similar avidity to npc domain cs derived from egyptian rousettes (ranpc ), hammer-headed fruit bats (hmnpc ) and bü ttikofer's epauletted fruit bats (ebnpc ), but poorly or not at all to that of african straw-colored fruit bats (ehnpc ) ( figure a ). like the infection defect in african straw-colored fruit bat cells, this receptor binding defect was selective for ebov gp, since gps derived from marv and the european filovirus, llov (ng et al., ) , bound equivalently to all four pteropodid domain cs ( figure a ). these findings the restriction in ehnpc -ebov gp binding can be mapped to a single amino acid change in ehnpc to define the molecular basis of the defect in interaction between ebov and ehnpc , we generated a panel of npc domain c chimeras comprising sequences from permissive ranpc and nonpermissive ehnpc , and tested them in the gp-binding elisa. a single chimera, ehnpc domain c containing four ehnpc firanpc amino acid residue changes, regained the capacity to efficiently recognize ebov gp ( figure b ). further dissection revealed that only a single amino acid change, f d, in a central region of npc domain c was needed to effect this complete restoration in gp- figure . the incompatibility between ebov gp and eidolon helvum npc reduces, but does not eliminate, ebov entry into african straw-colored fruit bat cells. (a) crispr/cas genome engineering was used to knock out the npc gene in african straw-colored fruit bat kidney fibroblasts. wt npc gene sequence aligned with the sequences of all three alleles in the knockout (npc -# ) cell clone. the grna target sequence is marked in red, and the protospacer adjacent motif (pam) sequence of the grna target site is underlined. (b) the capacity of wt and npc -# cells, and npc -# cells stably expressing hsnpc , to clear lysosomal cholesterol was determined by staining with filipin iii complex from streptomyces filipensis, as described (carette et al., ) . . we conclude that a species-specific defect in virus-receptor interaction, caused by a single amino acid residue change in ehnpc relative to other, permissive african pteropodid npc orthologs, reduces ebov infection in african straw-colored fruit bat cells. moreover, because residues in the npc -binding site are conserved among all available ebov gp sequences (supplementary file ), this restriction is almost certain to be encountered by all known ebov variants and their isolates, including those detected in ebov disease patients during the recent epidemics in western and middle africa gire et al., ; tong et al., ; carroll et al., ; kugelman et al., ) . previous work has led to the hypothesis that bats in equatorial africa and elsewhere harbor filoviruses (reviewed in [wahl-jensen et al., ] ). these results, together with our findings for virusand host species-specific differences in cellular susceptibility to filovirus infection, hinted at the possibility of a deeper co-evolutionary relationship between filoviruses and bats. one hallmark of such a relationship between a virus and its host is the evolution, under selective pressure to resist infection, of host genes encoding proviral and antiviral factors. to evaluate whether the npc gene has evolved under positive selection in bats, we combined the npc sequences obtained in this study with those of bats from six other species (two non-african pteropodids, two phyllostomids, and two vespertilionids) compiled through assembly of publicly available rnaseq data ( a mutation in ehnpc reduces receptor binding to ebov gp and viral infection, a phenotype that could reasonably produce a selective advantage (figure ) . other codons identified in only some of the tests for dn/ds> , or at slightly lower significance levels, may still have functional significance. for example, additional codons were identified in two regions of domain c that may form a part of the recognition surface for ebov gp ( figure c ). our finding that signatures of accelerated sequence evolution localize to structural features in npc that are important for virus binding (domain c and position ) leads us to postulate that mutations at these sites can protect bats from infection or severe disease caused by filoviruses and/or other intracellular microbes. a single mutation at residue in ebov gp enhances viral entry by strengthening its interaction with ehnpc co-evolutionary arms races between hosts and pathogens are thought to be driven by cycles of genetic adaptation and counter-adaptation (meyerson and sawyer, ; daugherty and malik, ; demogines et al., ) . in this context, we postulated that mutation of residue in ehnpc could be countered by viral mutation. to identify such putative compensatory viral changes, figure . a sequence polymorphism in the npc -binding site of filovirus gp influences gp-ehnpc binding and ehnpc -dependent filovirus entry. (a) binding of ebov gp (wt and mutant v a) to soluble npc domain c proteins derived from african pteropodids measured by an elisa. ranpc , egyptian rousette; ebnpc , bü ttikofer's epauletted fruit bat; hmnpc , hammer-headed fruit bat; ehnpc , african straw-colored fruit bat. (b) infection of african straw-colored fruit bat cells with vsv pseudotypes bearing ebov gp (wt or v a). means ± sd (n = - ) from a representative experiment are shown in each panel. means for vsv-ebov gp wt vs v a infection were compared by unpaired two-tailed student's t-test with welch's correction (**p < . ). (c) surface-shaded representation of a single gp -gp monomer (pdb id: csy highlighting key residues in the npc -binding site (yellow) and residue (red). gp , blue. gp , grey. (d) alignments of gp sequences from a panel of filoviruses. v , orange; a , white text on blue shading; other residues divergent from consensus sequence, black text on green shading. (e) infection of african pteropodid cells with vsv pseudotypes bearing sudv gp (wt or a v). means ± sd (n = ) from two biological replicates are shown. means for vsv-sudv gp wt vs a v infection on each cell line were compared by unpaired two-tailed student's t-test with welch's correction (*p < . , **p < . , ****p < . ). doi: . /elife. . we screened a panel of point mutants in the npc -binding site of ebov gp by elisa for enhanced binders to ehnpc domain c. while no single point mutant bound to ehnpc as well as it did to the other pteropodid npc s or to hsnpc , gp(v a) partially restored ehnpc binding ( figure a ). infection by vsv particles bearing ebov gp(v a) was substantially enhanced in african straw-colored fruit bat cells, commensurate with this mutant gp's increased binding affinity for ehnpc ( figure b) . examination of the x-ray crystal structure of ebov gp revealed that v is located at the edge of the putative npc -binding site, where it forms part of a raised rim ( figure c ). the v a mutation likely creates a more sterically favorable (open) npc binding site that can overcome the structural mismatch at the gp-npc binding interface ( figure c ). naturally-occurring sequence variation at residue in gp contributes to virus-and bat species-specific patterns of cellular susceptibility to filoviruses although no known ebov isolate contains the v a mutation, we observed that llov and sudan virus (sudv) gp naturally possess a ( figure d ). because both gp proteins could mediate efficient viral entry into african straw-colored fruit bat cells ( figure d ) and bind to ehnpc ( figure a data not shown for sudv), we postulated that amino acid changes at position in the gp receptor-binding site broadly influence the capacity of filovirus glycoproteins to utilize ehnpc for viral entry. accordingly, we exposed pteropodid kidney fibroblasts to vsv pseudotypes bearing sudv gp(wt) or sudv gp(a v) ( figure e ). consistent with our hypothesis, the a v mutation substantially reduced sudv gp-dependent infection in african straw-colored fruit bat cells. unexpectedly, this mutant virus also infected egyptian rousette cells significantly less well than wt, pointing to the existence of sequence context-dependent effects that selectively affect sudv gp(a v) binding to ranpc ( figure e ). these findings provide evidence that gp residue can influence cellular susceptibility to infection by modulating npc recognition in a manner that depends on the sequences of both proteins. we speculate that sequence variation at residue and potentially other positions in the receptor-binding site of filovirus glycoproteins has been shaped by selective pressure to utilize restrictive npc receptors, with potential consequences for viral host range and virulence. the ongoing, unprecedented ebola virus disease epidemic in western africa highlights the urgent need to uncover the biological and ecological factors that underlie the distribution, evolution, and emergence of filoviruses. while a full answer to this question will require the integration of knowledge across multiple levels of biological organization, from genes to populations to ecosystems, previous work has shown that studies of molecular interactions between viruses and their host cells can contribute important pieces to this puzzle. the essential interactions between viruses and their entry receptors provide particularly cogent examples. a switch in receptor binding from the feline to the canine ortholog of the transferrin receptor drove the emergence of a new virus, canine parvovirus, and fueled a global disease pandemic in dogs (allison et al., ) . analyses of interactions of sars-like coronaviruses with their receptor ace have helped to trace the emergence of sars coronavirus from bats to humans, and its use of civets as intermediate amplifying hosts ge et al., ; ren et al., ) . in this study, we show that interactions between filoviruses and their entry receptor npc can influence the cellular susceptibility of bats to infection. this observation is especially striking in light of previous findings that filoviruses could efficiently infect a broad range of mammalian cells, including some derived from bats (kuhn, ; kuhl et al., ) . indeed, this prior work and the results of experimental infection studies in rodents and bats have led to the hypothesis that interactions between viral components and those of the host innate and adaptive immune systems constitute the primary molecular variables influencing filovirus host range in nature (ebihara et al., ; volchkov et al., ) . here, we propose that npc is also a genetic determinant of filovirus susceptibility in bats. the essential nature of npc for infection in cells derived from mammals of multiple species, including bats (figure ) , and for infection and in vivo pathogenesis in lethal ebov infection mouse models argues against the existence of alternative filovirus entry receptors (carette et al., ; herbert et al., ) . therefore, strong reductions in the affinity of virus-npc recognition are predicted to reduce or eliminate infection in whole bat hosts, as observed in npc deficient mice (carette et al., ; herbert et al., ) , barring viral mutation to enhance this affinity. it is conceivable that even modest defects or delays in viral multiplication through such a mechanism could help determine host range by accelerating viral immune clearance, as recently observed in npc -heterozygous mice (herbert et al., ) , or by synergizing with other host-virus barriers. the highly virus-and host species-specific nature of the virus-receptor mismatch uncovered in this study warrants the determination of more bat npc sequences for inclusion in genetic analyses (see below), and a more comprehensive phenotypic examination of virus-bat pairs. such studies maydiscover additional interesting bat-filovirus dynamics, including incompatibilities between filoviruses and npc or other proviral/antiviral host factors. such discoveries have potential implications for our understanding of the molecular basis of filovirus infection, virulence, and host range. we found that a single amino acid change, at residue , in the african straw-colored fruit bat ortholog of npc (ehnpc ) greatly diminished the susceptibility of cells from multiple tissues and individuals to ebov. these migratory pteropodids are widely distributed across sub-saharan africa ( figure a) , roost in large colonies near human settlements, and host other rna viruses with zoonotic potential peel et al., ) . moreover, they are extensively hunted for bushmeat in western africa (kamins et al., ) , making them ideal candidates to transmit viruses directly to humans. unfortunately, there is little information currently available on the susceptibility of african straw-colored fruit bats to ebov or their potential role as filovirus hosts. serologic surveys have found some evidence for exposure to one or more filovirus; however, neither infectious virus nor coding-complete or full viral genomes-the gold standards-have been successfully obtained from these bats, indicating they may only have been exposed to filoviruses, rather than being productively infected (reviewed in [wahl-jensen et al., ; olival and hayman, ] ). while more extensive wildlife sampling and, if feasible, experimental infections of african straw-colored fruit bats will be required to clarify this picture, we can extrapolate to several possible scenarios. first, these bats are fully resistant to ebov, and therefore cannot be the source of this virus in the -present ebov disease outbreak in western africa or the outbreak in middle africa. second, because african straw-colored fruit bat cells do remain weakly susceptible to ebov ( figure c ), it is conceivable that they support ebov replication at low levels. indeed, this is one hallmark of a sustaining viral reservoir. third, the filoviruses circulating in these bats, whether ebov or otherwise, bear one or more gp mutations (e.g., v a) that circumvent the infection barrier imposed by ehnpc . assessing this last hypothesis and understanding the nature of the selection pressures that drive gp evolution in vivo will require the isolation of ebolavirus gp sequences from bats-there are none currently available. although these results suggest that african straw-colored fruit bats are selectively refractory to ebov, our genetic findings indicate that this is not merely a special relationship between one host and one virus. rather, we used a diverse set of bat npc sequences, only one of which is from african straw-colored fruit bats, to show that a number of codons, including residue , have evolved under recurrent positive selection. this is a process in which resistant npc variants are 'serially replaced' in response to compensating viral mutations that restore susceptibility. we provide evidence that the filovirus gp interaction surface in the second luminal domain of npc , domain c, is a hotspot for such positive selection ( figure ). by contrast, the vast majority of codons in mammalian npc have evolved under purifying selection. we propose that this pattern of selection is the signature of a long-term genetic conflict between filoviruses and npc in bats, superimposed over the normal evolutionary signature of a housekeeping gene with a critical role in cellular cholesterol trafficking. similar signatures of recurrent positive selection have been identified in other housekeeping genes that encode viral receptors, including the transferrin receptor (kaelber, et al., ; demogines et al., ) (tfr; receptor for new world arenaviruses [radoshitzky et al., ] , the betaretrovirus murine mammary tumor virus [ross et al., ] , and parvoviruses [parker et al., ] ), bat angiotensin-converting enzyme- (demogines et al., ) (ace ; receptor for sars-like coronaviruses [li et al., ] ), and mammalian dipeptidyl peptidase- (cui et al., ) (dpp ; receptor for mers-like coronaviruses [raj et al., ] ). in these cases as well, the preponderance of positively-selected residues localize to virus-receptor interfaces. interestingly, the sequence polymorphism at npc residue did not impair cholesterol clearance from lysosomes ( figure ) , and none of the residues under positive selection were found to be mutated in niemann-pick type c disease patients (runz et al., ; vanier and millat, ) . thus, despite being constrained by its housekeeping function, npc appears to retains a sizeable sequence space accessible to adaptive mutation. it is tempting to speculate that sequence variation at residue ( figure ) and potentially other positions in the receptor-binding site of filovirus glycoproteins represents the other half of the genetic arms race, shaped by selective pressure to utilize restrictive npc receptors. although more data, especially filovirus sequences from bats, are needed, our findings raise the tantalizing possibility that filoviruses, including those yet undiscovered, are each adapted to specific bat hosts, with co-evolved virus-receptor interactions constituting one potential biological barrier to interspecies viral transmission. alternatively, it is conceivable that repeated contacts between unknown (non-bat) reservoir hosts carrying specific filoviruses, and bats of particular species, have driven positive selection in bat npc to limit infection (and selection of filoviruses with compensating sequence changes in gp). in this scenario, detection of anti-filovirus antibodies or filovirus genome-derived oligonucleotides may reflect a type of spillover event from the actual filovirus reservoir hosts into bats. our hypothesis that npc in bats has been genetically sculpted by filoviruses (and vice versa) presupposes not only a long-term coevolutionary relationship, but also one in which these viruses have imposed selective pressure on bats to limit or eliminate infection. the discovery of filovirus np-and vp -related endogenous viral elements (eves) in bat genomes is consistent with such a long-term relationship (taylor et al., ; katzourakis and gifford, ) . to further investigate the deeper origins of filoviruses in bats, we screened all available bat genomes for filovirus-related eves. we obtained evidence for synteny between a filovirus nucleoprotein (np)-like eve in the genome of the big brown bat (eptesicus fuscus) and those previously identified in three, more distantly-related, myotis bats (figure and supplementary file ) (taylor et al., ) . this new discovery strongly suggests that all four eves resulted from a single insertion event prior to the divergence of the myotis and eptesicus genera, » million years ago (miller-butterworth et al., ) . therefore, bats may have been exposed to filovirus-like agents for far longer than previously recognized (» million years ago [taylor et al., ]) . available experimental exposure studies, although limited in number and scope, suggest that some filoviruses isolated from humans can replicate in bats without causing substantial host pathology (e.g., marv and ravv in egyptian rousettes jones et al., ; paweska et al., ] ). these observations therefore prompt a key question: what is the origin and nature of the selective pressure that has driven accelerated npc evolution in bats? our scant understanding admits a number of possibilities. first, it is conceivable that some filoviruses do indeed replicate in a manner that is deleterious to their specific bat hosts-we may simply not have identified the viruses and hosts in question. indeed, the filovirus llov, discovered in schreibers's long-fingered bat carcasses in spain and portugal, may exemplify this possibility (negredo et al., ) . alternatively, in some cases (e.g., ebolaviruses and egyptian rousettes), the human viral isolates used in challenge studies may differ from these bat isolates in important respects due to human adaptation (human ebov, bdbv, tafv, restv, and sudv isolates do not infect egyptian rousettes ). second, filoviruses may have been more virulent in bats in the past. thus, the positive selection signatures observed in bat npc , which cannot be accurately dated, may represent fixed alleles that are the consequence of a selective process driven by ancient filoviruses with properties distinct from their modern counterparts. indeed, the lack of virulence observed in some bats may reflect a dé tente that was shaped by precisely these historic genetic conflicts between filoviruses and bats. third, we cannot rule out the (unlikely) possibility that the evolution of npc in bats was driven by an entirely different infectious agent that also utilizes (or utilized) npc to multiply in its hosts. regardless of the mechanisms that genetically shaped npc , we propose that polymorphisms in this gene nevertheless impose host barriers that impede the colonization and spread of present-day filoviruses in bats in africa and elsewhere. our findings set the stage for broader explorations of species-specificity in filovirus interactions with proviral and antiviral host factors, with an eye to uncovering new molecular arms races between filoviruses and bats and new genetic determinants of filovirus host range and host switching. the following immortalized pteropodid fibroblast cell lines were used: roni/ . (kidney; rousettus aegyptiacus), hypni/ . (biesold et al., ) . the species origin of each cell line was confirmed in the publication in which it was first described (kuhl et al., ) . bat cell populations stably expressing human npc (hsnpc ) were generated as described previously (carette et al., ) . briefly, subconfluent monolayers of cells were transduced with a retroviral vector expressing hsnpc modified at the c-terminus with a triple flag epitope tag. transduced cells were selected by puromycin treatment ( mg/ml). licenses for capturing and export of bats, as well as ethical review and clearances of animal handling procedures were obtained from the ghana forestry commission of the ministry of food and agriculture. bat organ samples were obtained as described (drexler et al., ) . bats were caught, anesthetised with ketamine/xylazine and exsanguinated by heart puncture. carcasses were transported on ice to a nearby laboratory facility, and organs were dissected and immediately snap-frozen for long-term storage. animals were typed morphologically and genetically as described previously (kuhl et al., ) . vero african grivet kidney cells and t human embryonic kidney fibroblast cells were obtained from atcc. cell lines were maintained in dulbecco's modified eagle medium (dmem) (life technologies, grand island, ny) and supplemented with % fetal bovine serum (atlanta biologicals, flowery branch, ga), and % penicillin-streptomycin (life technologies). all cell lines were maintained in a humidified ˚c, % co incubator. we knocked out the npc gene in the eidni/ . cell line by crispr-cas -mediated genome editing as described previously (mali et al., ) . a crispr guide rna (grna) sequence to target '-gttgtgatgttcagcagcttcgg- ' in the e. helvum npc mrna was cloned into the grna cloning vector (addgene plasmid # ). eidni/ . cells were co-transfected with plasmid encoding human codon-optimized endonuclease cas (hcas , addgene plasmid # ), grna cloning vector encoding the e. helvum npc -specific grna, a monomeric red fluorescent protein (mrfp ) expression plasmid (to monitor transfection efficiency), and pmx-ires-blasti (confers blasticidin resistance to transfected cells) using lipofectamine (life technologies). at hr post-transfection, transfected cells were selected with mg/ml of blasticidin for hr and then allowed to recover in the absence of the selection agent. total rna was isolated from surviving cells with the rnaeasy mini kit (qiagen, valencia, ca) as per the manufacturer's directions. the e helvum npc mrna sequence flanking the grna target site was amplified with the one-step rt-pcr kit (qiagen) and the following primers: forward: '-at-tctggactaccaaaatctttgcc- ', and reverse: '-acatggcatccaagcccaag- '. thermocycling conditions used for the rt-pcr were: ˚c for min (reverse transcription), followed by ˚c for min (initial pcr activation), then cycles of ˚c for sec, ˚c for sec, ˚c for min, then a final extension of ˚c for min. amplified pcr products were tested for indels at the target site with the surveyor mutation detection kit for standard gel electrophoresis (transgenomic, omaha, ne), as per the manufacturer's instructions. once indels were confirmed, amplified pcr products from single cell clones were cloned into a topo-ta vector (life technologies). multiple clones for each single cell population were sequenced to confirm disruption of npc alleles. recombinant vesicular stomatitis indiana viruses (vsvs) expressing egfp, and ebov, marv, or llov gp in place of vsv g have been described previously wong et al., ; ng et al., ) . vsv pseudotypes bearing glycoproteins derived from vsv, ebov, bdbv, tafv, sudv, and marv were generated essentially as described previously (takada et al., ) . vsv particles containing gp cl were generated by incubating rvsv-gp-ebov with thermolysin ( mg/ml) (sigma-aldrich, st. louis, mo) for hr at ˚c. the protease was inactivated by addition of phosphoramidon ( mm) (sigma-aldrich), and reaction mixtures were used immediately. infectivities of vsv pseudotypes were measured by manual counting of egfp-positive cells using fluorescence microscopy at - hr post-infection, as described (chandran et al., ) . infectivities of rvsvs were measured in a similar manner, except that nh cl ( mm) was added to infected cell cultures at - hr post-infection to block viral spread, and individual egfp-positive cells were manually counted at - hr post-infection. the wild-type filoviruses ebola virus/h.sapiens-tc/cod/ /kikwit- (ebov/kik- ; "ebov-zaire ") and marburg virus/h.sapiens-tc/deu/ /hesse-ci (marv/ci ) used in this study were described previously swenson et al., ) . cells were exposed to virus at an moi of pfu/cell ( figure c ) or pfu/cell ( figure a ) for hr. viral inoculum was then removed, and fresh culture media was added. at hr (figure a ) or hr ( figure c ) post-infection, cells were fixed with formalin and blocked with % bovine serum albumin (bsa). ebov-infected cells and uninfected controls were incubated with ebov gp-specific monoclonal antibody kz (maruyama et al., ) . marv-infected cells and uninfected controls were incubated with marv gp-specific monoclonal antibody g (swenson et al., ) . cells were washed with pbs prior to incubation with either goat anti-mouse igg or goat anti-human igg conjugated to alexa . cells were counterstained with hoechst stain (invitrogen, carlsbad, ca), washed with phosphate-buffered saline (pbs), and stored at ˚c. infected cells were quantitated by fluorescence microscopy and automated image analysis. images were acquired at fields/well with a  objective lens on an operetta high content device (perkinelmer, waltham, ny). operetta images were analyzed with a customized scheme built from image analysis functions available in harmony software. from bats of four species (hypsignathus monstrosus, eidolon helvum, epomops buettikoferi, and, rousettus aegyptiacus), mrna was collected from cell lines (or spleen samples for additional eidolon helvum npc domain c sequences; figure -figure supplement ), cdna libraries were constructed, and the npc transcript was sequenced (see supplementary file for primers). using available rnaseq read data (supplementary file ), we assembled bat transcriptomes and identified npc sequences in bats of six additional species (myotis brandtii, artibeus jamaicensis, cynopterus sphinx, myotis lucifugus, pteropus alecto, and desmodus rotundus) . transcriptome data were cleaned with trimmomatic (bolger et al., ) and assembled using trinity (grabherr et al., ) and trans-abyss (robertson et al., ) . the -species npc alignment (supplementary file ) was analyzed for positive selection using the m codon model in the codeml package in paml (yang et al., ) , rel, and fel (pond and frost, ) , and meme (murrell et al., ) available at http://datamonkey.org/ (delport et al., ) . all evolutionary analyses were done using both the npc gene tree and a species tree ( figure -figure supplement ) . the species tree represents the accepted relationships amongst the bats analyzed (agnarsson et al., ; almeida et al., ) . to identify orthologous filovirus-related eve insertions, we screened bat genomes in silico for eves. a representative set of filovirus protein sequences was obtained from genbank, supplemented by the putative protein sequences of previously identified filovirus eves (taylor et al., ; taylor et al., ; taylor et al., ; katzourakis and gifford, ) . these sequences were used as 'probes' in tblastn screens of whole genome shotgun (wgs) sequence data derived from bats of ten species (eidolon helvum, eptesicus fuscus, myotis brandtii, myotis davidii, myotis lucifugus, pteropus alecto, pteropus vampyrus, megaderma lyra, pteronotus parnellii, and rhinolophus ferrumequinum) . statistically significant matches to filovirus probes were extracted, conceptually translated, and aligned with homologous filovirus proteins. orthologous flanking sequences were identified by blast comparison of eve-containing contigs. an alignment of the identified eves, along with the flanking information in the relevant bat genomes, is shown in supplementary file . a construct engineered to encode hsnpc domain c (residues - ) flanked by sequences that form a stable, antiparallel coiled coil, and fused to a preprotrypsin signal sequence with flag and hexahistidine tags at its n-terminus has been described (deffieu and pfeffer, ; . similar constructs bearing bat npc domain cs were generated by replacing the human domain c sequence with a sequence encoding domain c from each bat npc ortholog. soluble domain c was expressed in human -freestyle cells (invitrogen) and purified from supernatants by nickel affinity chromatography, as described previously . alternatively, cell supernatants containing soluble domain c were used directly for gp-npc binding elisas following calibration for domain c concentration (see below). npc domain c concentrations used in the elisas were normalized as follows. proteins were resolved by sds-page followed by immunoblotting with an anti-flag antibody followed by an antimouse alexa- secondary antibody (invitrogen). blots were visualized using the li-cor odyssey imager, and the domain c band was quantified using the li-cor image studio package (li-cor biosciences, lincoln, ne). thermolysin-cleaved vsv-ebov gp particles were captured onto high-binding -well elisa plates (corning, corning, ny) using kz , a conformation-specific anti-ebov gp monoclonal antibody. plates were blocked with pbs containing % bsa, and serial dilutions of npc domain c protein were then added. bound domain c was detected with an anti-flag antibody conjugated to horseradish peroxidase (sigma-aldrich) and ultra-tmb substrate (thermofisher, grand island, ny). all binding steps were carried out at ˚c for hr or at ˚c overnight. elisas with vsvs bearing llov and marv gp were performed as above, but with the following modifications. vsv-llov gp particles were cleaved by incubation with a reduced concentration of thermolysin ( . mg/ml, ˚c, hr) due to its enhanced protease sensitivity relative to ebolavirus gps, as described (ng et al., ) . the viral envelope was then labeled with biotin using a function-spacer-lipid construct (fslbiotin) (sigma-aldrich), as described previously (ng et al., ) . biotinylated viral particles were captured onto streptavidin-coated elisa plates ( . mg/ml). the remainder of the steps in the elisa were performed as described above for vsv-ebov gp. vsv-marv gp particles were cleaved by incubation with trypsin ( mg/ml, ˚c, min; sigma-aldrich), modified as above using fslbiotin, and captured onto streptavidin-coated magnetic beads (spherotech, lake forest, il). beads were then aliquotted into a -well round-bottomed plate for the remaining elisa steps. pbs containing % nonfat dry milk was used for blocking and washing steps. binding curves were generated by nonlinear regression analysis using prism ( -parameter logistic equation; graphpad software, la jolla, ca). to detect npc in primate or bat kidney fibroblasts, whole cell lysates were prepared as previously described . briefly, cells were washed with pbs and lysed in nte-chaps buffer ( mm tris [ph . ], mm nacl, mm edta, . % vol/vol -[( -cholamidopropyl)dimethylammonio]- -propanesulfonate) (sigma-aldrich) containing a protease inhibitor cocktail (roche, basel, switzerland), and placed on ice for min. to assist in cell lysis, cell suspensions were vortexed every min, and then placed on ice for min. samples were spun at , Âg for min, and supernatants harvested for western blot. in some experiments, proteins were deglycosylated with protein n-glycosidase f (new england biolabs, ipswich, ma) according to the manufacturer's instructions. proteins were resolved in % sodium dodecyl sulfate (sds)-polyacrylamide gels and transferred to nitrocellulose membranes. endogenous npc was detected using an anti-niemann pick c polyclonal antibody ( : , dilution; ab , abcam, cambridge, ma), followed by incubation with a donkey anti-rabbit antibody conjugated to horseradish peroxidase ( : , dilution, santa cruz biotechnology, dallas, tx). endogenous cyclin-dependent kinase (cdk ; loading control) was detected with a rabbit polyclonal antibody ( : , dilution; sc- , santa cruz biotechnology). ectopic expression of hsnpc -flag was detected with an anti-flag antibody conjugated to horseradish peroxidase (sigma-aldrich). bands were visualized by incubation with an enhanced chemiluminescence reagent (thermofisher) followed by exposure to x-ray film. in figure , cells were visualized using an inverted fluorescence microscope under illumination with a x high-numerical aperture oil objective ( figure b ) or a x air objective ( figure c ). images were captured with an axiocam mrm ccd camera using axiovision software (zeiss usa, thornwood, ny), and imported into photoshop (adobe systems, san jose, ca) for processing. images were cropped, inverted ( figure b) , and subjected to linear adjustment for overall brightness and contrast using the levels tool. developed x-ray films were digitized with a flatbed scanner and processed in photoshop as described above. statistical comparison of means among multiple independent groups was carried out by one-way analysis of variance (anova) with tukey's post hoc test for multiple comparisons. in some figures (see figure legends) , an unpaired two-tailed student's t-test with welch's correction for unequal variances (ruxton, ) was used for pairwise comparison of independent groups. all statistical analyses were performed in graphpad prism. the albert einstein college of medicine. opinions, conclusions, interpretations, and recommendations are those of the authors and are not necessarily endorsed by the us department of the army, the us department of defense, or the us department of health and human services. the funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. author contributions mn, en, mek, jmd, sls, kc, conception and design, acquisition of data, analysis and interpretation of data, drafting or revising the article; ash, rjg, acquisition of data, analysis and interpretation of data, drafting or revising the article; tb, aik, rmj, acquisition of data, analysis and interpretation of data; rkj, acquisition of data, analysis and interpretation of data, drafting or revising the article, contributed unpublished essential data or reagents; jah, my, acquisition of data, analysis and interpretation of data, contributed unpublished essential data or reagents; rb, acquisition of data, contributed unpublished essential data or reagents; ad, analysis and interpretation of data, drafting or revising the article; trb, conception and design, analysis and interpretation of data, drafting or revising the article; cd, mam, drafting or revising the article, contributed unpublished essential data or reagents; lfw, jhk, analysis and interpretation of data, drafting or revising the 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evidence that ebolaviruses and cuevaviruses have been diverging from marburgviruses since the miocene evolutionary maintenance of filovirus-like genes in bat genomes filoviruses are ancient and integrated into mammalian genomes genetic diversity and evolutionary dynamics of ebola virus in sierra leone isolation of genetically diverse marburg viruses from egyptian fruit bats niemann-pick disease type c molecular characterization of guinea pig-adapted variants of ebola virus roles of rodents and bats in human viral hemorrhagic fevers a forward genetic strategy reveals destabilizing mutations in the ebolavirus glycoprotein that alter its protease dependence during cell entry codon-substitution models for heterogeneous selection pressure at amino acid sites we thank tyler krause and cecelia harold for technical support, and gary crameri, shawn todd, and mary tachedjian for help with sourcing bat cdna for npc gene amplification. we also thank margaret kielian, jack lenz, max nibert, vinayaka prasad, deeann reeder, nancy simmons, and susan tsang for useful discussions. we thank laura bollinger, integrated research facility at fort detrick, for critically editing this manuscript.supported by grants from the us national institutes of health (ai to kc, gm to sls), the us defense threat reduction agency (hdtra - -c- to sls, cb to jmd), eu fp- antigone (grant ) and the ebokon project (to cd and mam). lfw is supported in part by an nrf-crp grant (nrf nrf-crp - ) in singapore. jhk performed this work as an employee of tunnell government services, inc., a subcontractor to battelle memorial institute, under battelle's prime contract with niaid (no. hhs i). sls is a burroughs wellcome fund investigator in the pathogenesis of infectious disease. kc is additionally supported by a harold and muriel block faculty scholarship and an irma t. hirschl/monique weill-caulier research award at key: cord- - io xux authors: kanmounye, ulrick sidney; esene, ignatius n. title: covid- and neurosurgical education in africa: making lemonade from lemons date: - - journal: world neurosurg doi: . /j.wneu. . . sha: doc_id: cord_uid: io xux abstract never in history has the fabric of african neurosurgery been challenged as it is today with the advent of covid- . even the most robust and resilient neurosurgical educational systems in the continent have been brought to their knees with neurosurgical trainees and young neurosurgeons bearing the brunt. in the face of this new reality, and in order to limit the impact of the current covid- pandemic, multiple programs have implemented physical distancing which reduces in-person interactions. in some cases, residents have been asked to stay home at least till they are instructed otherwise. this unfortunate event presents an innovative opportunity for neurosurgical education in africa. herein, we detail the framework of an online neurosurgical education initiative to advance the education of african residents and young neurosurgeons during and after the covid- pandemic. initiative to advance the education of african residents and young neurosurgeons during and after the covid- pandemic. seventeen of the african countries do not have the recommended specialist neurosurgeon workforce density principally due to a lack of training programs ( ) . also, few african training programs offer a wide range of neurosurgical subspecialty experience to their trainees. yet, some of the most respected neurosurgeons in the world are african neurosurgeons who have either trained on the continent or are training the future generation of neurosurgeons in their countries. these neurosurgeons are an estimable resource that we have underused. to reach greater heights, we must choose to stand on the shoulders of these giants. however, educational exchanges between our training centers are limited and pale in the face of the partnerships our training centers have with high-income country institutions. perhaps owing to the fact that it is generally cheaper and easier to travel outside of our continent than it is inside ( ) . we hope therefore that the african continental free trade area will facilitate the transfer of knowledge. in the meantime, however we must find alternative ways to share the skills and experiences of our senior neurosurgeons with the younger generation. african residents and young neurosurgeons are already learning from and about world renowned neurosurgeons via online medical education platforms ( ). it is clear from this that we can do a better job of integrating online medical education and our experts into our training programs. in order to limit the impact of the current covid- pandemic, multiple programs have implemented physical distancing which reduces in-person interactions. in some cases, residents have been asked to stay home at least till they are instructed otherwise ( ). this unfortunate event presents an opportunity for neurosurgical postgraduate medical education in africa. herein, we detail the framework of an online neurosurgical education initiative to advance the education of african residents during and after the covid- pandemic. led by the professional societies, senior faculty from all neurosurgical subspecialties and from all the regions will be invited to host continental neurosurgery grand rounds. with permission from program directors, residents will be recruited and will be asked to register online (google some speak of the return to pre-covid "normalcy" after the pandemic but it is more likely that the post-covid period will define a new "normalcy". one in which some things that were considered impossible before will not no longer be impossible. successful organizations adapt promptly in the face of adversity. while the post-covid surprised and tested our health systems, post-covid african neurosurgical education must reinvent itself and transform its potential into achievements. resilience in this situation lies in recognizing the value of learning from those who walked the path we wish walk and using technology to our advantage. we cannot let the current crisis stifle our progression and we should not aim to return to the pre-covid "normalcy". for when life gives you lemon, make lemonade! the neurosurgical atlas: advancing neurosurgical education in the digital age impact of covid- on neurosurgery resident training and education the authors declare no competing interest. usk and ie contributed equally to the conceptualization, writing, review and editing of the manuscript. the authors declare no competing interest. key: cord- - syce n authors: domínguez-andrés, jorge; netea, mihai g. title: impact of historic migrations and evolutionary processes on human immunity date: - - journal: trends immunol doi: . /j.it. . . sha: doc_id: cord_uid: syce n the evolution of mankind has constantly been influenced by the pathogens encountered. the various populations of modern humans that ventured out of africa adapted to different environments and faced a large variety of infectious agents, resulting in local adaptations of the immune system for these populations. the functional variation of immune genes as a result of evolution is relevant in the responses against infection, as well as in the emergence of autoimmune and inflammatory diseases observed in modern populations. understanding how host–pathogen interactions have influenced the human immune system from an evolutionary perspective might contribute to unveiling the causes behind different immune-mediated disorders and promote the development of new strategies to detect and control such diseases. the evolution of mankind has constantly been influenced by the pathogens encountered. the various populations of modern humans that ventured out of africa adapted to different environments and faced a large variety of infectious agents, resulting in local adaptations of the immune system for these populations. the functional variation of immune genes as a result of evolution is relevant in the responses against infection, as well as in the emergence of autoimmune and inflammatory diseases observed in modern populations. understanding how host-pathogen interactions have influenced the human immune system from an evolutionary perspective might contribute to unveiling the causes behind different immune-mediated disorders and promote the development of new strategies to detect and control such diseases. infectious diseases are arguably the main source of evolutionary pressure that humanity has ever confronted. the dispersion of different human communities around the globe has exposed each population to different infectious agents, exerting a selective pressure (see glossary) on them; thus, adaptation to the new environment has favored the selection of the most beneficial genetic variants for the host. as a result, infectious agents have caused the expansion of alleles behind the induction of either protection or tolerance to these diseases; heritable variations, that increased the survival to deadly infectious agents, may have been naturally selected before the hosts had the opportunity to reproduce [ ] . natural selection driven by pathogens is probably more remarkable for those infectious agents that have been among us for a longer time, namely the causative agents of well-known diseases such as leprosy, smallpox, malaria, or tuberculosis. the genetic imprint of pathogen-driven selection depends on the length and the virulence of the infections and also the geographical distribution. the human genome presents more than genetic loci with traces of selective pressure [ ] . this group includes more than immune-related genes with functional variations between populations, which are probably behind the variability of responses to immune-related diseases reported nowadays [ , ] . besides natural selection, other evolutionary mechanisms, such as genetic drift, greatly influence the frequencies of the genetic variants found within diverse populations throughout the world [ ] (box and figure ). with the burst of next-generation sequencing and the development of cutting-edge technologies such as transcriptomics, proteomics, and systems biology, we are starting to witness the great impact of evolutionary processes on human immunity and how the interactions between microorganisms and humans that took place millennia ago might play a fundamental role not only in the response against modern pathogenic threats, but also in the emergence of autoimmune and inflammatory diseases observed in modern populations worldwide. in this review we offer a novel perspective on the role of infectious diseases as agents of natural selection and as forces behind the evolutionary pressure encountered by human ancestors and modern humans in their migrations around the globe. specific genetic variants selected throughout different periods of human history may have influenced immune responses of present-day populations against pathogenic microorganisms and may have played a role in the development of certain inflammatory and autoimmune diseases. the majority of experts agree that africa is where our species originated. genetic studies conducted in diverse contemporary populations suggest connections with ancestors that lived on the continent up to years ago [ ] . human evolution has been constantly influenced by pathogens; therefore, a great number of human genes linked to immune functions and immunity-related disorders have evolved along with humans. the heterogeneity in the immune response to infectious diseases across different populations is under genetic control and is the result of evolutionary processes. genetic variants that have been under evolutionary pressure can contribute to explaining the differences in the susceptibility to diseases observed across different populations. the ancestry of individuals from different populations across the globe greatly influences their possibility of developing certain autoimmune diseases and inflammatory disorders. the lifestyle of western societies affects the symbiotic relationships between humans, viruses, and other organisms and might contribute to the rise of certain autoimmune and inflammatory diseases. pathogens have played a central role as agents of natural selection from those very early days. among various infectious diseases, malaria has exerted the highest evolutionary pressure on the communities across the african continent ( figure ) [ ] . populations remaining in sub-saharan africa have been exposed to malaria for such long periods of time that their genetic structures have been shaped by the severity of malaria (plasmodium sp.) infections. in , allison described that sickle cell disease distribution was confined to africa and was associated with the geographical presence of malaria [ ] . this finding led to the more recent description of the existence of mutations in the hemoglobin-b (hbb) gene as a result of natural selection driven by evolutionary pressure for protection against malaria [ ] (table ) . similarly to hbb, some areas of west africa with a high incidence of malaria the gene variations that pass from one generation to the next are often transmitted as a random process known as genetic drift, while selection of advantageous variants tends to be preferentially transmitted. mutations, genetic drift, migration, and environmental selective pressure are among the fundamental processes behind the evolution of humans. the influence of these mechanisms in the diverse communities that were mobilized and then became isolated, as well as severe external factors such as epidemics, caused successive genetic bottlenecks in populations (see figure in main text) [ ] . human evolutionary studies are currently considered under 'modern synthesis', which merges darwin's ideas of natural selection with theoretical population genetics and mendelian principles, stating that evolution occurs via small genetic changes that are regulated by natural selection [ ] . these beneficial adaptations subsequently expand within the members of a population and become evident in the ancestral specificity and the geographical distribution of the advantageous alleles in the genomes of contemporary humans. genetic bottlenecks occur when the number of individuals in a population is reduced drastically due to a catastrophic event such as an earthquake, a flood, a famine, or the outbreak of an infectious disease. these events limit the genetic variation of a population and can lead to genetic drift. as a result, a smaller population, with a correspondingly reduced genetic diversity, remains to transmit genes to future generations through sexual reproduction. even if this reduction in the genetic diversity is temporary, it can lead to long-lasting effects on the genetic variation of the offspring populations. genetic drift: changes in the allele frequencies of a population over generations due to chance. genetic locus: fixed position on a chromosome (e.g., the position of a gene or a genetic marker). histocompatibility complex: region of approximately kb, located on human chromosome , that contains a large number of genes whose products are expressed as proteins on immune cells. of these genes, the best known are hla genes. introgressive hybridization: incorporation of genes from one species into the genetic reserves of another by interspecific hybridization and backcrossing with the parent species. present a high frequency of hemoglobin-c (hbc) in their populations, which is associated with a - % decrease in the possibility of developing the disease [ ] . this is also the case for the duffy antigen receptor gene (darc) in erythrocytes and single nucleotide polymorphisms (snps) in human leukocyte antigen (hla), which have been associated with protection against plasmodium vivax malaria in certain areas of africa where this disease is endemic [ , ] . another example of natural selection driven by evolutionary pressure for protection against malaria are thalassemia (a and b) pathologies, a group of hemoglobin disorders that presents an incidence of up to % among communities of west africa [ ] . the human casp t c snp, expression of which is restricted to the african subcontinent, south america, and certain areas of asia, can modulate immune and inflammatory responses to malaria by antagonizing interleukin (il)- b and nf-kb signaling in innate immune cells; moreover, caspase -deficient mice (casp -/-) exhibit decreased interferon (ifn)-g production and clearance of the parasite, relative to wild type (wt) infected mice [ ] . however, others have questioned these findings, given that caspase -deficient mice also lack caspase expression, so the effects observed might not be specific to caspase [ ] . mycobacterium tuberculosis (mtb) has caused infections in our species and ancestors for at least years [ ] . this long-standing relationship between humans and mtb probably underlies the large variety of immune-related factors that modulate susceptibility to mtb infection, including vitamin d receptor (vdr), natural resistance-associated macrophage protein (slc a ), tir domain containing adaptor protein (tirap), hla, monocyte chemoattractant protein (mcp- ), and cytokines such as il- and ifn-g [ ] ( table ) . patients with african ancestry present a higher frequency of mtb-related genetic variants than individuals from other populations, including variants in the gene encoding for toll-like receptor (tlr ), mediating cellular responses to bacterial malaria is one of the greatest causes of morbidity and mortality in the history of humanity. most human populations with a long history of endemic malaria have evolved genetic adaptations to malaria parasites due to the strong selective pressure that this infection has exerted. since the parasite infects erythrocytes, the evolutionary pressure has selected genetic variants that affect red blood cells and, therefore, the survival of the parasite as well. genetic variants conferring resistance to the disease have spread through human populations over time, including several abnormal hemoglobins that protect against malaria but usually cause erythrocyte-associated diseases in the populations where these adaptations are prevalent. these factors include the t c polymorphism in the caspase gene (casp ); the hemoglobin b (hbb) and hemoglobin c (hbc) variants; mutations in the duffy antigen receptor gene (darc); thalassemias (a and b); sickle cell disease; and polymorphisms in the human leukocyte antigen (hla) loci. dna nucleotide. for example, an snp may replace cytosine (c) with thymine (t) in a certain segment of dna. selective pressure: phenomenon that alters the behavior and fitness of living organisms within a given environment. it is the driving force of evolution and natural selection. thalassemias (a and b): inherited hemoglobinopathies characterized by a failure in the synthesis of the globin alpha or beta chains. toll-like receptors: family of transmembrane pattern recognition receptors expressed by immune and nonimmune cells that recognize conserved pathogenassociated molecular patterns. they play a pivotal role in innate immunity. transgenerational inheritance: transmission of traits from generation to generation. trends in immunology, december , vol. , no. lipoproteins [ , ] . selective pressure has also shaped the mechanisms that modulate the expression of genes implicated in immune responses against lassa virus, such as il- (il ) and the glycosyltransferase-like protein large (large), suggesting that the natural selection exerted by the virus drove the expansion of genetic variants that enhance immunity against lassa fever [ ] . these examples indicate that infectious diseases have contributed to shaping the genetic landscape of african populations and their descendants, and highlight the great impact of pathogens as an evolutionary force in humans. our homo sapiens ancestors were not the only species to venture out of africa, with other homo species performing a similar migration much earlier, such as homo ergaster, homo erectus, or homo heidelbergensis [ ] . from these early migrations, local populations such as the denisovans and neanderthals evolved [ ] . these lineages were not geographically isolated, but lived side by side with modern humans and interbred with them, leaving a genetic footprint in their common progeny. accordingly, - % of the genome of european and asian populations is thought to derive from these now-extinct hominid lineages [ ] . neanderthals spent close to years adapting to their environment and their immune systems were shaped by the infections they faced. by interbreeding with archaic humans, modern humans incorporated these advantageous adaptations in the genome of their descendants. this was highlighted by different studies that showed that the introgression of diverse genes related to immune functions, such as the oas cluster, tlr , or the histocompatibility complex from denisovans and neanderthals shaped the genetic landscape of present-day eurasian, but not african, communities. genomic sequences and expression data from lymphoblastoid cell lines from individuals of european and african ancestry confirmed that the tlr -tlr -tlr genetic loci, presenting signs of local positive selection and repeated introgression from both neanderthal and denisovan genomes [ ] [ ] [ ] , showed a significantly higher expression in individuals carrying archaic-like alleles than in individuals carrying the nonintrogressed modern human alleles [ , , ] . the expression of these genes has shaped human immune responses against different types of pathogens. for example, the gp protein of the hiv- virus has been recently recognized as a tlr ligand [ ] . in this regard, increased tlr expression has been correlated with higher il- production by the macrophage cell line thp- and higher titers of hiv- in the breast milk of hiv- -infected nigerian women relative to controls [ ] . tlr and tlr form dimers with tlr , triggering immune responses against different types of bacteria, fungi, virus, and parasites [ ] . variation in tlr -tlr -tlr is the major genetic determinant of human interindividual differences in tlr / -mediated responses, including cytokine production to a number of clinically relevant pathogens such as staphylococcus aureus and listeria monocytogenes [ ] (table ). this inheritance from archaic humans may have also left some human individuals more prone than others to developing asthma, hay fever, and other allergies (of snps associated with susceptibility to allergic disease, had a neanderthal or denisovan origin) [ ] , although these associations remain to be fully demonstrated [ ] . these reports demonstrate that by interbreeding with archaic humans, modern humans incorporated a group of advantageous adaptations to the genome of their descendants and contributed to shaping immune responses in modern human populations. the migration of our human ancestors out of africa implied the exposure to different types of infectious diseases (box and figure ). one study tested the responsiveness of human macrophages to pathogenic bacteria in vitro, finding that almost % of the genes present in human macrophages infected with the bacteria salmonella typhimurium or l. monocytogenes present different regulatory responses directly linked to the lineage of the donors and, also, that macrophages obtained from individuals of african origin display enhanced bactericidal activity compared with those from individuals of european lineage [ ] . the trend towards lower inflammatory responses in european populations is strengthened by the fixation of a tlr gene variant that results in lower proinflammatory gene expression in populations with a european ancestry compared with those with an african one [ ] . the largest population differences in gene expression between africans and europeans have been found in the macrophage receptor with collagenous structure (marco), a protein implicated in responses against viral infections and tlr-induced dendritic cell activation [ ] , the chemokine receptor cx cr , which mediates effector lymphocyte functions, and also several ifn-stimulated genes [ ] . west eurasian populations present a high frequency of tirap ser leu snps [ ] . tirap is an adaptor protein in tlr and tlr signaling pathways, involved in inflammatory responses and cytokine production. the heterozygous expression of the ser leu snp is protective against invasive pneumococcal disease, bacteremia, malaria, and tuberculosis, as shown in a case-control study of individuals from the uk, vietnam, and several african countries, and it is associated with lower tlr signaling in humans [ ] . this variant is considered to be a consequence of the natural selection that may have taken place in an early period following the migration of modern humans out of africa [ ] . european populations present a selective adaptation of the ifn gene that allows a high production of ifn-g in infectious scenarios due to the positive selection of ifng variants + g and + t; this suggests the existence of strong environmental pressures linked to higher ifn-g concentrations in plasma during mtb infection in european individuals relative to other populations [ , ] . in line with this, a database meta-analysis showed that individuals expressing the + t/a variant of ifng presented higher susceptibility to tuberculosis mtb infection than individuals without it, which might be considered a putative prognostic factor for the development of tuberculosis [ ] , although this remains to be robustly demonstrated. one of the most interesting aspects of humans is their ability to adapt to almost every ecosystem of the planet. the history of mankind is also the history of millions of individuals wandering around the world, looking for a better place to live. a glimpse to the migratory legacy of humanity around the globe reveals the great impact that the massive population movements defined the world as we know it today (see figure in main text). the distances ancient humans travelled are impressive, from the first hominids colonizing africa to the conquest of the americas in a time when the bering strait was not yet under water. the historical exodus of mankind started almost million years ago with the migration of homo erectus from africa through eurasia. from this event on, relatively isolated human populations evolved separately on different continents, leading to the emergence of different human species, such as neanderthals in europe, the denisovans in asia, and, later, modern homo sapiens in africa [ , ] . h. sapiens first colonized large areas of the continent around years ago [ ] , spread towards the middle east at some point between and years ago, and migrated through eurasia, reaching australia within years [ ] . asian human ancestors went through the frozen waters of the bering strait in two distinct waves to colonize the american continent approximately years before the present time [ ] . when humans ventured out of africa, they faced different types of pathogens than the communities that stayed in the african continent. with time, the series of events faced by diverse populations has generated differences in the immune responses to pathogens in the populations with an african or eurasian origin and which have spread throughout the world. the indigenous populations of south america are descendants of migrating populations of north-east asians that crossed the bering strait around years ago [ ] . five centuries ago, european settlers disembarked on the american continent, bringing a large collection of pathogens such as those causing measles, pneumonic plague, and influenza infections, which the indigenous populations had never faced before. these diseases rapidly spread and caused mortality rates above % [ ] . the consequences of these pandemics are still visible in current populations; one report studied dna from the bones of ancient humans from the tsimshian community, living in the british columbia region in canada until the th century, identifying marks of positive selection in a number of immune-related variants [ ] . specifically, the hla-dqa variant was present in almost the totality of tsimshian individuals, but only in one third of present-day humans studied; this suggested that ancient american genomes were evolutionarily selected to respond to local diseases but not to fight against pathogens brought by the europeans [ ] . another study compiled information on infectious diseases that have killed more than individuals among indigenous communities of the amazonia in the past two centuries, showing that the mortality rates and the incidence of infectious diseases rapidly decayed within the time following the first encounter with the pathogen, compatible with genetic adaptation [ ] . european colonizers underwent purifying selection in situations of intense pressure. such scenarios were documented when dutch colonists migrated to surinam and encountered epidemics of yellow and typhoid fever that caused a % mortality rate among settlers [ ] . variations in the frequencies of c , glo, and hla-b genes among the descendants were not likely caused by genetic drift, but rather, it has been proposed that these populations were probably selected through genetic control of survival to the epidemics [ ] (box ). africans and americans with an african ancestry present a much higher number of genetic variants related to robust inflammatory reactions, increased cytokine secretion, and bactericidal activities compared with the other populations [ ] , including more than genes with traces of recent selection, such as il a and il b gene variants [ ] . the degree of african ancestry, analyzed by fine-mapping analysis refined to the duffy-null allele of rs , was correlated with an increased amount of the proinflammatory chemokines ccl and ccl in plasma relative to controls [ ] . a study involving african american and hispanic american women found that the higher values of c-reactive protein (crp) in blood found in these populations compared with european americans were related to a crp-associated variant of triggering receptors expressed by myeloid cells (trem ) [ ] . moreover, comparison of health record data from individuals with connective tissue diseases, including rheumatoid arthritis and systemic lupus erythematosus (sle), as well as atherosclerotic cardiovascular disease from almost african american and european american adults was conducted; the study reported for the latter, a prevalence of atherosclerotic cardiovascular disease in . % african americans (particularly high in young individuals), relative to . % in european americans [ ] . these studies highlight certain genetic links to inflammatory predisposition/manifestation. however, increased proinflammatory activity is a double-edged sword. in the absence of regular pathogen challenges that require maintained modulation of the balance between inflammation and suppression of the immune response, the organism can overreact to inflammatory stimuli and trigger exacerbated responses. for instance, descendants of african populations generally present higher susceptibility to a variety of autoimmune syndromes such as inflammation-associated carcinomas, lupus, asthma, and multiple sclerosis (ms), the overall prevalence of which is up to three times higher in individuals with african ancestry relative to individuals with european ancestry [ , , ] . there are extensive differences in immune cell gene expression between americans with african and european ancestry. the increased proinflammatory responses observed in american individuals relative to other populations might be beneficial to combatting infections, but might also increase the chances of developing inflammatory and autoimmune disorders, which warrants further investigation. our gastrointestinal tract provides residence to both beneficial and potentially pathogenic microorganisms, harboring ten million different microbial genes in the human fecal microbiome [ ] . the microbiome has its own evolutionary scenario across different populations with divergent lifestyles, nutrition, and exposure to environmental agents, generating extraordinary heterogeneity. the ongoing process of 'lifestyle westernization' of different societies has an important impact on the mutualistic relationships between humans and commensal organisms worldwide. african tribes are adopting western subsistence patterns, leading to remarkable changes in the composition of their microbiota [ ] . the comparison of the intestinal flora of the baaka hunter-gatherers and the bantu agriculturalists (both from the central africa republic), with a group of us-born african americans showed a great example of the evolution of the human microbiome [ ] . specifically, the bantu, still engaged in hunting, have a greater bacterial gut diversity than their baaka neighbors, who left the jungle for agriculture, and even more than urbanized westerners (us african-americans) [ ] . this reduced microbiota diversity in western societies has been associated with a higher incidence of the so-called 'diseases of civilization' such as cardiovascular diseases, diabetes, obesity, and autoimmune disorders, which are very unusual in hunter-gatherer societies compared with communities living a western-type lifestyle [ , ] . although viruses are mainly seen as pathogenic agents, they also play a fundamental role in the evolution and maturation of the human immune system [ , ] . approximately % of the human genome is composed of endogenous retroviruses (ervs), sequences derived from past retroviral infections and permanently inserted into different regions of the human genome [ ] . one study showed that ervs played a central role in the induction of ifn-dependent immune responses and that the removal of one or more of these viral dna elements in the hela human cell line severely impaired the recruitment of transcription factors necessary to trigger the expression of ifng against vaccinia virus infection relative to controls [ ] . viruses can also influence the severity of infections caused by other viruses. for example, cytomegalovirus infection in hiv- seropositive humans can potentiate the effects of hiv- infection by expanding the pool of circulating regulatory t cells (immunosuppressive); these were shown to inhibit the proliferation of autologous peripheral blood mononuclear cell the origins of the hiv virus are still a matter of scientific discussion. the most accepted scenario argues that hiv originated in simians and was transmitted to humans in west africa in the s, likely due to local ingestion of ape meat infected with the simian immunodeficiency virus. around , the virus reached wide parts of the continent and finally spread overseas thanks to a group of haitian professors coming back from africa. in the following decades, the virus spread worldwide and generated the pandemic we now know. today, there are approximately million people worldwide living with hiv- /aids [ ] . ccr is a receptor of chemokines that plays a fundamental role in hiv- pathogenesis and it is also one of the most promising targets to restrict the infection, since mutations in this receptor turn individuals resistant [ ] . the ccr -d mutation results in a deletion that eliminates the hiv- co-receptor on lymphocytes, providing robust protection against hiv- and, therefore, aids [ ] . ccr -d allele frequencies reach % in northern europe populations, whereas it is not present in populations with different ancestry, such as east asian, native american, or african groups [ ] . this regional distribution of ccr -d variants is most likely related to a naturally selective episode that struck european populations around years ago and involved a strong infectious agent that also employed ccr [ ]. a mathematical model studying the changes in the european populations in the middle ages suggested yersinia pestis (bubonic plague) as the most probable infectious agent behind the pressure that selected this particular genetic variant [ ] . this is in agreement with the finding that european rroma populations, but not northwestern indian populations that inhabit the area where the rroma originally lived, present signatures of positive selection in tlr -tlr -tlr , which influence cytokine responses in y. pestis infections [ ] . (pbmc) in response to cytomegalovirus infection in vitro [ ] . in one study, patients with chronic hepatitis c virus (hcv) infection and hepatitis a virus (hav) superinfection presented lower titers of hcv rna than patients harboring only hcv, suggesting that hcv replication might be potentially suppressed during hav infection [ ] , although this will still require further investigation. the relationships between humans and pathogenic or nonpathogenic organisms are extraordinarily complex and include tripartite evolutionary interactions between humans and microbes competing with each other. this is the case of parasites that infect other parasites, such as bacteriophage viruses, that can influence the outcome of bacterial infections. for example, in a cohort of individuals with chronic wounds, a report showed that the phage pf, which coexists with pseudomonas aeruginosa in infected wounds, triggered the production of type i ifn, the inhibition of tumor necrosis factor (tnf) production, and the suppression of phagocytosis in human primary monocytes and mouse bone marrow-derived macrophages, dampening the antibacterial response and promoting the bacterial infection [ ] . however, bacteriophages can also provide protection to the human host by directly attacking pathogenic bacteria and by upregulating in human pbmcs the expression of proinflammatory genes such as il a, il b, il , tnfa, cxcl , and cxcl , as shown for several s. aureus and p. aeruginosa phages, including pnm, luz , - , and ge-vb_pae-kakheti [ ] . cooperative relationships between organisms are evolutionary processes themselves. the way microorganisms and their hosts associate can lead to interactions of mutualism, in which the interplay may be so intimate as to provide benefit for each party and influence immune responses against different types of pathogens. a great number of humans live far away from the original settlements of their ancestors and are subject to radically different environmental conditions. between two and three million people with european genealogy suffer from autoimmune diseases, the prevalence of which is also increasing in other populations across the globe [ ]. there is rising evidence that the emergence of autoimmune diseases is associated with the presence of a number of immune-related alleles that have been selected via evolutionary processes; and, furthermore, that the contrasting differences in the prevalence of autoimmune diseases between populations may be a result of different selective pressures [ ] . alleles associated with inflammatory diseases that present marks of modern positive selection include the risk allele fut at rs for crohn's disease (cd) or the risk variant sh b at rs for celiac disease [ ] ; such variants have been linked to the development of several human autoimmune diseases, such as type diabetes, ms, and celiac disease [ , ] . the analysis of the integrated haplotype score [ ] of loci associated with sle that might provide protection against infections, such as tnip , itgam, ptpn , tnfsf , uhrf bp , tet -dguok, and blk, has suggested that these loci exhibit robust signs of positive selection [ ] (figure , key figure and table ). african and asian human populations exposed to trypanosoma brucei or plasmodium sp. have presented positive selection of snps in the apol and fcgr b genes; indeed, by enhancing human macrophage-mediated phagocytosis of infected erythrocytes, despite their association with an sle predisposition, these snps have been associated with protective roles against sleeping sickness and malaria, respectively [ , ] . an analysis of human loci associated with inflammatory bowel disease (ibd) concluded that the majority of the loci associated with cd are also linked with a higher risk of developing ulcerative colitis [ ] ( table ). many of these loci were also associated with the development of other autoimmune diseases, namely psoriasis and ankylosing spondylitis [ ] . pbmcs from individuals carrying the sh b variant rs *a (associated with a risk for developing cd) [ ] presented higher production of il- and il- b after stimulation with lipopolysaccharide or muramyl dipeptide due to enhanced activity of the nod inflammasome pathway relative to controls [ ] ; this has suggested an immune-related role for sh b in the context of bacterial infections, which might help explain the positive selection of sh b approximately years ago [ ] . others found an association between genetic variants in nod , cd , and increased susceptibility to cd [ ] , in line with previous results showing that mutations in nod and tlr /cd are related to an increased risk of developing ibd [ ] . from another angle, changes in hygiene patterns seen in the past two centuries brought vast improvements in sanitation, drinking water, and garbage collection, which greatly reduced the exposure to many infectious diseases. however, these conditions may have reduced the exposure to viral and microbial agents that help the immune system to develop tolerance during childhood. the hygiene hypothesis proposes that the lack of exposure to microbial agents in the early stages of life is related to a higher risk of developing hypersensitivity reactions, based on the fact that children that are exposed to higher amounts of microbial stimuli (e.g., by growing on farms) are less prone to develop allergies and asthma [ , ] . moreover, reduced exposure to infectious agents can have a much wider effect than initially believed. lack of exposure to microbes in childhood can cause aberrant responses to infection and potentiate the effects of etv -runx mutations in the pathogenesis of acute lymphoblastic leukemia [ ] . by contrast, a meta-analysis of six observational studies, including participants, showed a correlation between low helicobacter pylori infection and ms, suggesting that low h. pylori prevalence might be a putative protective factor in ms, although this remains to be experimentally validated [ ] . one study also reported that antibodies against toxoplasma gondii were detected less often in patients with ms compared with healthy controls [ ] . however, these findings warrant further and robust investigation. overall, it is clear that evolutionary processes can drive the fixation of genetic variations that increase (or decrease) our defense against infections upon sensing microbial ligands, but can also lead to a greater risk of developing certain autoimmune diseases in which endogenous ligands can cause tissue damage and inflammation. a growing number of reports suggest that inheritance is not always governed by classical darwinian evolutionary processes. exposure to certain environmental stimuli can cause effects in the progeny of an exposed individual, even though the stimuli are no longer present. this type of transgenerational inheritance might be explained through the effects of epigenetic processes, which are hypothesized to be transmitted through the germline and passed on to the offspring [ ] . for example, the worm caenorhabditis elegans can transmit improved resistance to infections to pathogenic bacteria to their offspring through alterations of the histone landscape [ ] . indian meal moths exposed to low doses of virus are subsequently less susceptible to viral challenge, a protection offered to their offspring as well [ ] . transgenerational inheritance of diverse traits has also been observed in mice, in which the variation of the color of the coat is passed on the next generation [ , ] . offspring of male rats subjected to a high-fat diet present glucose intolerance and reduced insulin secretion, linked to reduced methylation at the il ra gene relative to controls [ ] ; and mice fed scorpions are more resistant to a challenge with scorpion venom than mice on a normal diet [ ] . since infections are one of the strongest factors impacting survival, it is conceivable that transgenerational transmission of traits in mammals, including humans, evolved to improve host defense. the number of studies of the potential role of epigenetic inheritance in shaping the human immune system is still scarce. however, different experiences undergone by certain communities indicate that these mechanisms might be important. for example, the babies of pregnant women who suffered during the early stages of pregnancy (the effects of the dutch hunger winter in ), years later showed reduced dna methylation marks in several genes that control metabolism and cell differentiation during development, such as igf , pim , txnip, abcg , pfkfb , and mettl , compared with their siblings [ , ] . this was related with higher rates of obesity, heart disease, cancer, and depression in individuals whose pregnant mothers suffered the effects of the famine [ , ] . some of these effects seemed to be present in the progeny of this group, that is, in the grandchildren of those who had passed the famine during pregnancy [ ] . the rapid growth in the number of reports covering the impact of epigenetic mechanisms in different human processes warrants further and robust studies on the impact of epigenetic inheritance in shaping the evolution of the human immune system. human immune responses have been shaped by the evolutionary pressure exerted by microorganisms and viruses throughout history. generating a broad range of genetic variations and immune functions in different populations favors the adaptation to new environments and increases the chance of survival of the human species against potential pandemics. much remains to be learned in this exciting field over the coming years in order to identify the main regulatory forces and the time window necessary for the fixation of an advantageous genetic trait in a population (see outstanding questions). the combination of the selective pressure caused by infectious diseases with other evolutionarily relevant processes, such as genetic drift, migratory events, bottlenecks, and introgressive hybridization, contribute to driving the expansion, fixation, or elimination of characteristic immune response-related traits in different populations around the world. these specific genetic variants are able to boost the host response against pathogens by improving the sensing of microbial ligands but can also lead to the development of autoimmune diseases, in which the immune system responds to endogenous ligands and induces abnormal responses targeted against the host's own tissues. of note, it is very difficult to assign certain variants, a specific role in the protection or induction of autoimmunity. to assign changes in the genetic landscape of human populations to certain diseases is an extraordinary challenge. moreover, our species is in constant evolutionary interaction with various microorganisms and viruses. populations of bacteria and their viruses (phages) undergo, under natural conditions, reciprocal evolution in terms of resistance and infection; this, in turn, also affects the evolutionary traits of our immune system. thus, an extraordinarily complex scenario exists in which organisms of different phyla interact, compete, and coevolve, to ensure their own survival. as novel tools, the development and refinement of methods that study large sections of the human genome, epigenome, and microbiota, will help to obtain genome-wide data in diverse human populations, allowing us to follow the evolutionary trails left from the encounters with different organisms, further unveiling the roots of human immunity. high-throughput biotechnology and an expanding computational capacity can enable the study of global population genomics and might contribute to decoding the origin and consequences of functional changes in adaptive alleles down to the single cell level. however, these methods also have limitations associated with the difficulty in linking gene variations to clinical phenotypes and disease, the generation of false positives, or the high number of samples necessary to reach reliable conclusions. expanding the heterogeneity of populations studied for immune gene association studies relevant to disease will be key, as generally, a large focus is placed on certain european or american communities, thus generating results that are difficult to extrapolate to other populations. the knowledge of the evolutionary and genetic basis of human immune traits and their impact on diverse pathologies (e.g., autoimmunity, infections, inflammatory diseases, cancer) increasingly suggests that the genetic basis of disease may be derived from a large number of rare variants of modest effect. the mechanisms described here acquire special importance in the current scenario of world globalization, in which the migration fluxes and the admixture of different populations are reaching unprecedented levels, allowing faster expansion of advantageous alleles. however, these processes may also accelerate the spread of new epidemics, as seen in the cases of hiv infection, or more recently, sars-cov, ebola, and chikungunya viruses; as well as the emergence of multiresistant bacteria and fungi, such as methicillin-resistant s. aureus or candida auris. this is just the starting point to unveil the evolutionary history of the relationships between pathogens, the immune system, and humans. further investigation of the functional adaptations of human populations is warranted to provide a broad picture of the functional consequences of evolution in human immunity. acknowledgments m.g.n. is supported by a spinoza grant of the netherlands organization for scientific research and an erc advanced grant (# ). the funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. we thank laszlo a. groh for which are the strongest evolutionary forces that drive the evolution of the human innate immune system? how long does the genome of a given population take to adapt to a new infectious threat? are the mechanisms of resistance to infection transmitted only via genetic modifications, or can epigenetic adaptations to resistance also be transmitted to the progeny, and under what circumstances? the development of single-cell sequencing technologies has opened new fields of study. how does genetic variation of the expression of a specific variant vary between different cell subsets and how does it affect the overall phenotype of an individual within a population? are there specific immune processes that are preferentially impacted by evolutionary pressures? in western societies we enjoy a life expectancy vastly superior to that of our predecessors, but at the same time, we suffer diseases that they did not suffer. can some of the reasons for these changes lie among some of those bacteria that we have somehow lost in our microbiome? identifying these bacteria and understanding their effects on the human body might be the first step to developing putative therapies based on bacterial restoration. since many of the variants causing autoimmune diseases are linked to an enhanced responsiveness to pathogens that is no longer needed in developed countries, could these genes and their related pathways be employed as targets for new putative therapeutic approaches against inflammatory/ autoimmune syndromes? are other newly described genetic regulatory pathways, such as interfering rna or long noncoding rnas, also influenced by pathogen-driven evolutionary processes in different populations globally? proofreading and correction of the manuscript. we additionally thank srinivas agra for providing the figure icon 'bacteria' as deposited on https://thenounproject.com. natural selection and infectious disease in human populations genomic signatures of selective pressures and introgression from archaic hominins at human innate immunity genes genome-wide identification of regulatory sequences undergoing accelerated evolution in the human genome divergent selection of 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severe malaria full-exon resequencing reveals toll-like receptor variants contribute to human susceptibility to tuberculosis disease multiple common variants for celiac disease influencing immune gene expression epitope selection for hla-dq presentation: implications for celiac disease and viral defense card /nod mutational analysis and genotype-phenotype correlation in patients with inflammatory bowel disease association of nod leucine-rich repeat variants with susceptibility to crohn's disease nod and nod : beyond peptidoglycan sensing global, regional and countrylevel - - estimates for : assessing progress towards the targe key: cord- - hmzgwrw authors: izzy, saef; tahir, zabreen; cote, david j; al jarrah, ali; roberts, matthew blake; turbett, sarah; kadar, aran; smirnakis, stelios m; feske, steven k; zafonte, ross; fishman, jay a; el khoury, joseph title: characteristics and outcomes of latinx patients with covid- in comparison to other ethnic and racial groups date: - - journal: open forum infect dis doi: . /ofid/ofaa sha: doc_id: cord_uid: hmzgwrw background: there is limited understating of the impact of covid- on the latinx population. we hypothesized that latinx patients would be more likely to be hospitalized and admitted to the icu than white patients. methods: we analyzed all patients with covid- in massachusetts hospitals between february and april , . we examined the association between race, ethnicity, age, reported comorbidities, and hospitalization and intensive care unit (icu) admission using multivariable regression. results: of covid- patients, % were hospitalized; % required icu and . % died. % of patients were white, % latinx, % african american, and % asian american. ethnicity and race were significantly associated with hospitalization. more latinx and african american patients in the younger age groups were hospitalized than whites. latinx and african americans disproportionally required icu, with % of hospitalized latinx patients requiring icu compared to % of african americans, % of asian americans, and % of whites (p& . ). within each ethnic and racial group, age and male gender were independently predictive of hospitalization. previously reported pre-existing comorbidities contributed to the need for hospitalization in all racial and ethnic groups (p& . ). however, the observed disparities were less likely related to reported comorbidities, with latinx and african american patients being admitted at twice the rate of whites, regardless of such comorbidities. conclusions: latinx and african american patients with covid- have higher rates of hospitalization and icu admission than white patients. the etiologies of such disparities are likely multifactorial and cannot be explained only by reported comorbidities. the health, societal, and economic impacts of coronavirus disease (covid- ) have been felt worldwide, with nearly million confirmed infections leading to more than , deaths by early july , with numbers continuing to grow. [ ] [ ] [ ] studies from china, italy, spain and the united states have identified several factors associated with symptomatic infection and hospitalization, with or without admission to intensive care units (icu). [ ] [ ] [ ] [ ] [ ] [ ] older age has been shown to significantly increase the risk for hospitalization and death. , hypertension, heart disease, obesity, and diabetes are common comorbidities associated with hospitalization in covid- patients. , , , most of these published reports either describe the disease in relatively homogenous ethnic and racial populations, or they do not compare covid- infected patients who did and did not require hospitalization. in the united states, where a racially and ethnically diverse population has been exposed to infection in the setting of known racial and ethnic health disparities, several news reports have suggested that ethnic and racial minorities, especially latinx and non-latin african american individuals, may bear a higher burden of disease during the covid- pandemic. [ ] [ ] [ ] [ ] [ ] these reports also propose that such disparities are due to higher rates of pre-existing comorbidities in latinx and non-latin african american patients. other than these limited reports, the association between ethnicity and, race, and reported pre-existing comorbidities as risk factors for hospitalization and icu admission in covid- patients, has yet to be examined in a large, ethnically and racially diverse population. in this paper, we hypothesized that there are ethnicity and race-related disparities in hospitalization and icu admission for covid- patients regardless of age and reported pre-existing comorbidities. we used medical records available from the largest not-for-profit healthcare system in massachusetts to examine the association between age, race and ethnicity, reported preexisting comorbidities, and the need for hospitalization and icu admission in a large study population of covid- positive patients. mass general brigham is a not-for-profit healthcare system affiliated with harvard medical school that comprises m a n u s c r i p t the design of the study was approved by the mass general brigham institutional review board (irb) who deemed that the study does not include factors necessitating patient consent. we used data reporting functions available through the electronic health record (epic systems, verona, wi) shared by all mass general brigham healthcare system institutions. we collected data on all patients years or older who tested positive for covid- during an inpatient, outpatient, or emergency room visit between february , and april , . we revisited the records on april , to collect follow up data on mortality and other outcomes. patients who presented to mass general brigham institutions with symptoms of fever, cough, sore throat, fatigue, muscle aches, new anosmia, who were exposed to someone who tested positive for covid- , or if referred by a healthcare provider were tested per specified testing criteria/guidelines set forth by the institution. patients were diagnosed as infected with covid- if sars-cov- rna was detected in upper or lower respiratory specimens by nucleic acid testing (nat) assays designated for emergency use authorization (eua) by the food and drug administration (fda) and in accordance with the centers for disease control and prevention (cdc) guidelines. , each assay targets at least one sars-cov- gene region; positive results are reported for each assay as defined by the manufacturer or reference laboratory. hospitalization at any time during the course of the illness and admission to an icu at any time during hospitalization were primary endpoints. patients who were discharged home initially but were admitted later were categorized as hospitalized patients. patients hospitalized for longer than the follow up period were censored for study outcomes. we extracted the following covariates from the electronic health records for all patients: age, gender, patient-reported race (white, african american, asian american or pacific islander, other, or unknown), patient-reported ethnicity (latin or non-latin), smoking status, and the presence of recorded metabolic diseases including obesity (as measured by body mass index [bmi]), diabetes mellitus, and hyperlipidemia. the presence of organ-specific disease included hypertension, coronary heart disease, congestive heart failure, chronic obstructive pulmonary disease, asthma, m a n u s c r i p t interstitial lung disease, cerebrovascular disease, chronic kidney disease, end stage renal disease, malignancy including hematologic malignancy (lymphoma, leukemia), hiv, and history of organ or bone marrow transplantation. missing data were imputed by multiple imputation using the amelia package in r. the multiple-imputation models used all baseline data. bmi and smoking status for all patients were also imputed by multiple-imputation models using r, and imputations were carried out in total under the assumption that data were missing at random. data for median household income and population density were obtained from census data reported by the census bureau for the state of ma, and were linked to patient by zip code of reported residential address. because immunocompromised patients generally demonstrate increased susceptibility to respiratory viral infections, we analysed our study population of patients for history of solid organ transplantation (sot), lymphoma, leukemia or hiv to assess whether these factors were associated with hospitalization or icu admission. as appropriate, descriptive analyses of variables are presented as proportions or medians with interquartile range (iqr) for all endpoints (not hospitalized, hospitalized, admitted to icu). categorical data were compared using chi-squared tests, while t-test was used for continuous variables to identify univariable associations. multivariable logistic regression models were constructed to identify factors associated with hospitalization and icu admission. we tested our assumption that data were missing at random by constructing logistic regression models for missingness using all of the variables included in multiple imputations. we further examined the association between racial and ethnic background and hospital admission by comparing proportions of endpoints for each -year age interval from to . we also examined the association between racial and ethnic background, pre-existing comorbidities, and hospitalization or icu admission by stratifying by number of baseline comorbidities ( vs. ≥ ) and race and ethnicity. we further performed a sensitivity analysis with adjustment for socioeconomic status as a predictor for hospitalization/icu admission for patients from massachusetts state with median household income data available. patients with median household income less than th percentile ($ , ) were classified to have low ses as a dichotomous variable. statistical significance was defined as p< . for all analyses, and all statistical analysis was completed using r v . . . we graphed the geographic representation of the confirmed covid patients during our study using microsoft excel version . . a total of , patients were diagnosed with laboratory confirmed covid- in the time frame of the study and were included in our analysis (figure ) . out of the total study population, , ( . %) were hospitalized. overall, hospitalized patients were more likely to be male ( % vs. %, p< . ) and older (median vs. years, p< . ) compared to non-hospitalized patients. hospitalized patients were also more likely to be obese ( % vs. % bmi - kg/m , p< . ), with on average more cardiovascular and pulmonary risk factors, and more comorbid conditions compared to non-hospitalized patients ( table ) . the most common comorbidities in the hospitalized study population were hypertension ( %), hyperlipidemia ( %), diabetes ( %), and obstructive lung disease ( %). the mortality rate was higher in hospitalized compared to nonhospitalized patients ( % vs. . %, p< . ). our test of the missing at random assumption demonstrated significant predictors of missingness for all variables for which imputation was conducted. among the total covid- positive patient study population, , ( %) were white, , were latinx ( %), were african american ( %) and were asian american ( %). ethnicity and race were significantly associated with the rate of hospitalization. latinx and african american patients were more likely to be admitted to the hospital than white patients ( . % and . %, respectively, vs. . % for white patients). overall latinx, african american, and asian american hospitalized patients were younger compared to white patients (median age , and , vs. respectively, p< . , table ). subgroup analyses of the ages between - at -year intervals showed that in each age group, latinx and african american patients were more likely to be admitted as a result of covid- compared to white patients (p< . for each comparison, figure ). for example, among those - and - years old, latinx and african american patients were admitted to the hospital at the rates of ( % and % vs. %, and % and % vs. %, in comparison to. white patients respectively, p< . for each comparison). we observed similar, among those aged > (supplementary table ) . with regard to reported comorbidities, hospitalized latinx patients were more likely to be obese in the range of - kg/m ( % compared to % among white and % among african american patients, p< . ). however, the proportions of white, latinx and african american patients who were in range of > kg/m were similar. white patients had higher rates of reported hyperlipidemia, hypertension, obstructive lung disease, coronary artery disease, congestive heart m a n u s c r i p t failure, chronic kidney disease and malignancy compared with other groups (p< . , table , supplementary table ) . when stratified by baseline reported comorbidities, latinx and african american patients were admitted at twice the rate of whites, regardless of whether they had reported preexisting comorbidities (p< . , table ). compared to non-hospitalized patients, univariable logistic regression stratified by race identified pre-existing comorbidities including metabolic, cardiovascular, cerebrovascular, pulmonary and kidney disease as predictors for hospitalization in all racial and ethnic groups (p< . , supplementary table ). most of these predictors remained significant after adjustment for socioeconomic status (supplementary table ). based on patients' zip-code data, % of all the patients who tested positive lived in zip codes with median income between $ , -$ , , of which % were hospitalized. a higher proportion of hospitalized latinx and african american patients lived in those zip codes ( % and % respectively, compared to % of white patients, figure a, supplementary table ) . interestingly, smaller proportions of patients living in zip codes with income <$ , were hospitalized (supplementary table ). in addition, residence in a zip-code with greater density of living per household was corelated with a higher likelihood of hospitalization (figure b, supplementary table ). in our study population, % of admitted patients were from areas residence with population density > , /square mile. a history of solid organ transplantation was associated with a significantly increased risk for hospitalization (p< . ). of the transplant patients who were covid- positive ( kidney recipients, three liver recipients, four heart recipients, two lung recipients and one heart/lung recipient) seventeen ( %) were admitted. in contrast, hiv, lymphoma or a history of leukemia were not associated with increased risk for hospitalization or icu admission (supplementary table ). a possible difference between sot patients and those with hiv or a history of lymphoma or leukemia, is that sot patients were universally immunosuppressed at the time of infection while the degree of immune impairment for other groups was likely more heterogeneous. m a n u s c r i p t latinx and african american patients disproportionally required admission to the icu compared to white patients. overall, % of hospitalized latinx patients required admission to the icu compared to % of african american patients, % of asian american patients and % of white patients (p< . , table ). the presence of reported metabolic or organ-specific comorbidities was not significantly associated with need for icu admission (supplementary table ) . in multivariable regression analysis, age greater than years old (or= . , %ci: . - . for latinx, or= . , %ci: . - . for african american patients) and obesity with bmi > kg/m (or= . , %ci: . - . for latinx patients), and diabetes (or= . , %ci: . - . for african american patients) were identified as significant predictors of icu admission ( table ). in addition to these predictors, low median household income was as a significant predictor for icu admission in white patients (or= . , % ci: . - . ) after adjustment for socioeconomic status (supplementary table ). in spite of aggressive efforts by the medical and public health communities worldwide, understanding of the overall impact of the covid- pandemic remains limited. based on data from china, italy, and spain, and preliminary data from the united states, patients who are years or older are more vulnerable to covid- , with higher morbidity and mortality. [ ] [ ] [ ] [ ] [ ] [ ] furthermore, patients with other comorbidities, such as cardiovascular disease and hypertension, are more likely to be hospitalized and die from the infection. , , , this evidence mostly derives from studies performed in racially and ethnically homogeneous populations. , the impact of the disease in an ethnically and racially diverse population has not been fully explored. anecdotal and news reports and a report from the uk suggest that racial and ethnic minorities may be more likely to contract covid- , and more likely to suffer poor outcomes as a result of infection. [ ] [ ] [ ] [ ] [ ] price-haywood et al. and others showed that the majority of patients hospitalized with covid- and of those who died in a louisiana study population were african american. , our firsthand clinical experience with covid- patients indicate that in addition to african american patients, a higher percentage of covid- latinx patients required hospitalization and critical care admission. to examine this issue, we investigated the impact of covid- on the patient population covered by our group of hospitals, which serve a diverse and broad population of eastern massachusetts similar to the racial and ethnic compositions of many large metropolitan areas of the united states. we confirmed that age, male gender and obesity are indeed important risk factors m a n u s c r i p t for worse outcomes after covid- infection, and that the presence of reported comorbid medical conditions is an important contributing factor to hospitalization among all ethnic and racial groups. three additional important findings emerged from our study. first, analysis of our large study population confirmed our firsthand clinical experience and showed indeed that latinx and african american patients are at higher risk of being hospitalized and admitted to icu level of care with covid- , than white patients. a second important finding is that the differences observed between latinx and african american vs. white patients occur at all age groups and are not only limited to the "higher risk" older age groups identified in prior studies. a third important finding is that the observed disparities appear to be less likely related to reported pre-existing medical comorbidities, since latinx and african american patients who tested positive for covid- were admitted at twice the rate of whites, regardless of whether they had reported comorbidities or not. in addition, the proportion of white patients who had reported comorbidities such as hyperlipidemia, hypertension, obstructive lung disease, coronary heart disease, cerebrovascular disease was at least as great as the proportions of latinx and african american patients who have these comorbidities. the underlying etiology of such disparity in hospitalization from covid between latinx and african american vs. white patients is likely multifactorial. first, patients from these historically disadvantaged racial and ethnic groups may be less likely to be insured than white patients. immigration status could also play another role in restricting access of racial and ethnic minority patients to health insurance coverage and increase their challenges in finding a source of care to get tested or accessing covid related treatments. therefore, they may have presented at a later, more severe phase of the disease and therefore required hospitalization. in support of this, when we analyzed the zip-code of residence of these patients we found a close correlation between residence in a zip code of low median income and greater density of living in the same household with higher rate of hospitalization. in general, lower income patients tend to defer seeking healthcare for fear of financial burden and/or limited health care access and quality. second, it is possible that latinx and african american patients with covid have a higher severity of reported comorbidities. our data do not show that such disparities in hospitalization can be explained by the presence of reported comorbidities. however, there are limitations to our interpretation of these data. because our findings are based on reported data in the medical records, they do not take into account the severity of the preexisting conditions, which is difficult to quantify in such a large study population. it is likely that the severity of certain underlying comorbidities is higher in ethnic and racial minorities than in white patients, perhaps due to previously described healthcare disparities, , or to issues with medication use and adherence. [ ] [ ] [ ] third, other issues of stress and allostatic load that could impact health, which were out of the scope of our observational study may also be contributing factors to the observed disparities and require further investigation. , these include crowded housing conditions as we alluded above, or the type of employment where exposure to covid could possibly be more common. our study has several possible limitations. first, this is a registry database study from a single mixed health system (with primary and tertiary institution) using structured data captured in the a c c e p t e d m a n u s c r i p t electronic medical record. this study may also underrepresent covid patients who do not seek medical attention or have whose medical data are stored at other facilities. however, the strengths of this study include a large, diverse study population of covid- positive patients from a wide geographic region that allowed us to analyze a large number of latinx, african american, asian american in addition to white patients. we were also able to collect detailed sets of variables on each patient, including factors that predict hospitalization and icu-level care, which allows for multivariable adjustment. follow up identified a number of outcome events, including deaths and icu-level admissions. while we acknowledge the limitations of our study, reporting data based on societal understanding of race and ethnicity, using patient self-reported race and ethnicity, is an important step in highlighting existing disparities in covid- treatment and try to mitigate contributing factors for the future. , our findings also could have immediate policy implications, since it would be crucial to target the most vulnerable groups when testing or vaccination strategies are devised to limit further spread of covid- and minimize its impact. this is especially relevant with the new surge in the numbers of covid cases in states where latinx patients constitute a significant portion of the population such as florida and texas. m a n u s c r i p t table and figure legends table . characteristics of all covid- positive patients in the mass general brigham healthcare system. table . baseline characteristics by race and ethnicity among admitted covid- patients. table . rate of hospitalization among all covid- patients by baseline comorbidities and race and ethnicity. *the household income and population density reported are obtained from county-level census data. dr. ross zafonte serves on the scientific advisory board of oxeia biopharma, biodirection, elminda, and myomo. he also evaluates patients in the mgh brain and body-trust program which is funded by the nfl players association. the remaining authors declare no conflict of interests. m a n u s c r i p t iqr=interquartile range, copd=chronic obstructive pulmonary disease, chf=congestive heart failure, ckd=chronic kidney disease, esrd=end stage renal disease *missing for % of population **missing for % of population 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coronavirus disease (covid- ) -united states does comorbidity increase the risk of patients with covid- : evidence from meta-analysis epidemiological and clinical characteristics of cases of novel coronavirus pneumonia in wuhan, china: a descriptive study the changing racial and ethnic composition of the us population: emerging american identities african american covid- mortality: a sentinel event covid- and african americans kills-latinxs-and-african americans-in-new-york-city.) . interim guidelines for collecting, handling, and testing clinical specimens from persons for coronavirus disease (covid- ) income statistics and demographics for states, counties, cities and zip codes risk factors for sars-cov- among patients in the oxford royal college of general practitioners research and surveillance centre primary care network: a cross-sectional study hospitalization and mortality among african american patients and white patients with covid- . nejm . . population health statistics: 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-eham trt authors: lor, aun; thomas, james c.; barrett, drue h.; ortmann, leonard w.; herrera guibert, dionisio j. title: key ethical issues discussed at cdc-sponsored international, regional meetings to explore cultural perspectives and contexts on pandemic influenza preparedness and response date: - - journal: int j health policy manag doi: . /ijhpm. . sha: doc_id: cord_uid: eham trt background: recognizing the importance of having a broad exploration of how cultural perspectives may shape thinking about ethical considerations, the centers for disease control and prevention (cdc) funded four regional meetings in africa, asia, latin america, and the eastern mediterranean to explore these perspectives relevant to pandemic influenza preparedness and response. the meetings were attended by health professionals, scientists, academics, ethicists, religious leaders, and other community members representing countries in these regions. methods: we reviewed the meeting reports, notes and stories and mapped outcomes to the key ethical challenges for pandemic influenza response described in the world health organization’s (who’s) guidance, ethical considerations in developing a public health response to pandemic influenza: transparency and public engagement, allocation of resources, social distancing, obligations to and of healthcare workers, and international collaboration. results: the important role of transparency and public engagement were widely accepted among participants. however, there was general agreement that no "one size fits all" approach to allocating resources can address the variety of economic, cultural and other contextual factors that must be taken into account. the importance of social distancing as a tool to limit disease transmission was also recognized, but the difficulties associated with this measure were acknowledged. there was agreement that healthcare workers often have competing obligations and that government has a responsibility to assist healthcare workers in doing their job by providing appropriate training and equipment. finally, there was agreement about the importance of international collaboration for combating global health threats. conclusion: although some cultural differences in the values that frame pandemic preparedness and response efforts were observed, participants generally agreed on the key ethical principles discussed in the who’s guidance. most significantly the input gathered from these regional meetings pointed to the important role that procedural ethics can play in bringing people and countries together to respond to the shared health threat posed by a pandemic influenza despite the existence of cultural differences. before the ebola outbreak in west africa captured the world's attention, one of the most feared yet widely anticipated events in public health was a pandemic of highly pathogenic influenza. in the th century, there were three notable influenza pandemics -the "spanish flu" (h n virus) in and , which resulted in approximately million deaths worldwide ; the "asian flu" (h n virus) in [ ] [ ] , which resulted in - million deaths worldwide , ; and the "hong kong flu" (h n virus) in , which resulted in million deaths worldwide. , in the late s and in early s, concern focused on the spread of avian influenza virus h n to humans. the first cases of human infection with h n were reported in in hong kong ( cases of which were fatal). [ ] [ ] [ ] [ ] fears about h n were heightened in when the virus was found to be responsible for serious disease and death in humans. nearly human cases of h n have been reported from countries since through october . other outbreaks led to questions about preparedness. the outbreak of severe acute respiratory syndrome (sars) in contributed to growing concern about the world's ability to prepare for and respond to a worldwide epidemic. sars, first reported in asia in february , is a viral respiratory illness caused by a coronavirus. the illness spread rapidly to more than two dozen countries in north america, south america, europe, and asia before the sars global outbreak was contained in . the reemergence of the h n virus during the - influenza season, the emergence of the middle east respiratory syndrome coronavirus (mers-cov) in , and the cases of severe illness in humans from a new avian influenza a (h n ) virus in heightened concerns about the need to be prepared for pandemics. an influenza pandemic results in a sudden surge of people with acute health needs, placing extra burden on health resources already overstretched in many places. the severity and suddenness of these burdens can create ethical tensions along a number of fronts. one such tension to which policymakers already have given considerable attention is the ethical allocation of scarce supplies of antivirals, vaccines, respirators, and personal protective equipment. [ ] [ ] [ ] [ ] healthcare workers will encounter challenging ethical dilemmas involving their professional duties to patients and their strong competing obligation to protect and care for themselves and their family. the employers of these workers will have obligations to minimize risks to their employees, while countries will have obligations relating to international collaboration that can compete with domestic priorities. at the request of member states, the world health organization (who) convened an international group in to identify common ethical concerns in preparing for and responding to a pandemic influenza and to provide preliminary guidance on how to address these issues. this resulted in the release of ethical considerations in developing a public health response to pandemic influenza. in addition to discussing general ethical considerations (eg, balancing rights, interests and values, transparency and community engagement), the who ethics guidance discussed issues relating to priority setting and equitable access to therapeutic and prophylactic measures; use of isolation, quarantine, border control and social distancing measures; and the role and obligations of and to healthcare workers. an overriding theme for the who guidance was the need for international cooperation and the importance of taking into account the contextual and cultural considerations of particular countries or regions. the who document notes that "ethical considerations will be shaped by the local context and cultural values. " cdc also developed ethical guidance relating to pandemic influenza. , this guidance focused on ethical issues relating to allocation of scarce resources and use of public health interventions which may limit individual liberties. in addition to the who and cdc documents, there is considerable literature devoted to ethical considerations in pandemic influenza preparedness and response. [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] however, whereas most of this literature assumes a liberal democratic perspective in considering ethics and values, many countries that would partner in a global pandemic response are more hierarchically structured. in hierarchical societies, citizens tend to implicitly expect and trust decisions from their leaders. notwithstanding that liberal democratic societies emphasize individual autonomy, collective decision-making and the interrelatedness and interdependence of community members are fundamental to every human society. because in hierarchic societies these factors have greater visibility, in such societies the success of public health interventions will depend on engaging recognized tribal, community or religious leaders in decision-making. recognizing the importance of having a broader exploration of how cultural perspectives may shape thinking about ethical considerations, cdc sponsored meetings in africa, asia, latin america, and the eastern mediterranean to explore various cultural perspectives relevant to pandemic influenza preparedness and response. the meeting in africa was held in collaboration with who and the african field epidemiology network (afenet) in kampala, uganda on august - , ) in sharm el sheikh, egypt on december - , . the key objectives for all four meetings were to: ( ) identify culturalspecific ethical challenges in pandemic influenza detection and control, ( ) explore approaches for addressing these ethical challenges, including how to best integrate ethical considerations into country/regional pandemic influenza preparedness and response guidelines and implementation strategies, and ( ) begin establishing a social network to foster continued discussion about ethical issues in the practice of public health. the meetings were attended by government health officials and policy-makers, public health practitioners, scientists from academic and research institutions, epidemiologists, philosophers, ethicists, religious leaders, and representatives of international aid and health organizations. the african meeting was attended by people, including representatives from african countries (nigeria, south sudan, south africa, zimbabwe, togo, mali, cameroun, burkina faso, tanzania, kenya, egypt, and uganda). the asian meeting was attended by people, including representatives from countries (cambodia, china, india, indonesia, laos, myanmar, philippines, thailand, and vietnam). the latin america meeting was attended by people, including representatives from latin american countries (argentina, brazil, columbia, costa rica, dominican republic, el salvador, guatemala, honduras, mexico, panama, and peru). the eastern mediterranean meeting was attended by people, including representatives from countries (egypt, afghanistan, pakistan, sudan, yemen, iraq, jordan, and morocco). for this paper, we reviewed the reports, notes, and stories resulted from the four regional meetings. we mapped outcomes from the meetings to five key ethical challenges identified in the who guidance: transparency and public engagement, allocation of resources, social distancing, obligations to and of healthcare workers, and international collaboration. we report here the objectives, processes, and ethical issues discussed at these meetings as they relate to the who key ethical challenges. in addition, each of the coauthors of this paper attended at least one of the four meetings. description of processes used in organizing the regional meetings to ensure that everyone had the basic knowledge needed to engage in the discussions, all meetings began with overviews of influenza biology, epidemiology, and history, including lessons learned from past influenza pandemics and the sars pandemic. the focus of the meetings was on planning for a highly pathogenic h n influenza; however, the h n influenza was running its course during the asian meeting and discussion of that epidemic entered the conversation. information was presented on the who and cdc ethics guidance documents as a starting point for discussing how ethical considerations may differ between countries. in addition, there were presentations on the basic principles of public health ethics and how it differs from more traditional clinical and research ethics approaches, and discussion of ethical challenges that are likely to arise in response to planning for and responding to pandemic influenza. the latin america meeting also included a session on human rights. out of respect for local partners, somewhat different processes were used in the four meetings to generate discussion of ethical issues. in the african meeting, participants met in small groups to discuss pre-developed case studies addressing the topics of non-pharmaceutical interventions, obligations of healthcare workers, and equitable access to treatment and prophylaxis. participants were asked to consider the case in light of specific challenges they may face in their countries. in the asian meeting, participants met in small groups and were asked to develop their own short narratives about the ethical issues they thought would be important in a pandemic influenza and how the values and cultural consideration in their counties would impact approaches for addressing these ethical issues. participants wrote short narratives answering the following prompt: prior to this meeting, a close friend explains that he does not understand why ethical issues are important in a pandemic response. what experience, either yours or someone else's would you share to illustrate the significance and importance of public health ethics in a pandemic response? during the latin america meeting, participants, grouped by country, were asked to identify key points for integrating ethics into emergency plans. during the eastern mediterranean meeting, participants were asked to share stories about ethical issues encountered during public health responses and to discuss how these issues were addressed in their response plans. organizers took minutes and notes of meeting proceedings and developed summary reports for all meetings. unpublished reports are available at request. for each of the organizing topics below, we first present some common themes discussed at the four meetings followed by more specific perspectives from each of the meetings in chronological order of when the meetings were held, beginning with african perspectives (august ), followed by asian perspectives (march ), latin american perspectives (july ), and eastern mediterranean (december ) perspectives. the who framework was used as a starting point for discussion at all meetings, but due to the characteristics, nature of events, and interests of local partners, discussions were not always focused on the same issues. discussions at the two latter meetings were by-andlarge affirming of the perspectives discussed at the two former meetings. based on the meeting reports, fewer details related to the ethical challenges emerged from the latin america and eastern mediterranean meetings than are for the africa and asian meetings. transparency, in which relevant information is made freely available, and public engagement were seen by participants at all meetings as factors critical to an effective response during a pandemic influenza emergency. many related issues were discussed, including low literacy level, poverty, and trust of and/or deference to health authorities. some cultural variations were expressed; for example, that certain societies more readily accept autocratic directives for disease control. participants at all meetings affirmed that their cultures do not tolerate corruption and indicated that a lack of transparency raises suspicions of corrupt dealings. government authorities and leaders are expected to be open and consult the community in making important decisions, including public health emergency decisions, affecting their people. factors that complicate mass communication that were discussed at all meetings include low levels of literacy, the inaccessibility of media such as television, newspapers, and the internet because of poverty; and the unavailability of the internet and cell phone towers in some rural areas. although the detail and depth of discussions regionally varied and some cultural variation was evident, transparency in decision-making was in general decisively affirmed. at the african meeting, in contrast to the general perception that "big men" and individuals with centralized power make all of the decisions, participants agreed that traditional cultures expect leaders to seek input from those they lead, through elder councils and similar institutions. participants noted that public health leaders include traditional healers who serve as both recipients of and conduits for information. because many africans will seek care from traditional healers during a pandemic, these health providers must also be informed of how to protect themselves from infection, and how to guard against spreading the infection. in addition, a wide variety of local and international non-governmental organizations (ngos), often funded by high-income countries, are active in resource poor countries in africa seeking to meet the populations' most basic needs. thus, it is important that both traditional healers and ngos be engaged in the decisionmaking process. the participants at the asian meeting varied widely in their views and practices relating to informing and engaging the public. for example, when sars broke out in one asian country, the government issued mandatory public health measures and expected public compliance. due to the culture of deference to authority, nearly all communities in this country instantly adopted the measures (eg, quarantine, isolation, and social distancing). however, not all participants reported such deference to authority. this was reflected in a story from another asian country about a boycott of a government polio immunization campaign by a minority community due to suspicions about the government's motives. others reported that when the central government was perceived as misgoverned or weak, responsibilities for informing the public about health threats and providing leadership during emergencies fell to local leaders. participants at the latin american meeting stressed that community participation and cooperation will be crucial during a pandemic influenza response, particularly for migrants or minorities who are already stigmatized. latin american participants also pointed to the importance of the media and health authorities in communicating health information and avoiding panic, as well as to convey factual information about availability and access to therapeutics. some participants were concerned about the wide disparity in resources within and between countries, which make transparency even more important. participants at the eastern mediterranean meeting emphasized the need for inclusion, accountability, and transparency in public health policies, but also noted the reluctance among countries to collaborate because of political differences and disparity in wealth and resources. participants discussed the need to establish a clear understanding of who will make what decisions during an emergency, how guidelines will be established, and the importance of considering multiple perspectives, including perspectives from individuals most at risk. allocation of scarce resources economic, demographic, geographical, and population vulnerability factors were common challenges identified as affecting resource allocation decisions. these challenges were shared in all regions where the meetings occurred. participants agreed that because of the cultural and regional variations, a "one size fits all" approach to any planning and response activity is unlikely to be optimal and should be questioned and challenged. however, although differences were acknowledged, there were also shared understanding and general agreement on the importance of the ethical values discussed at the meetings. participants felt that planning and response should take into account contextual variations and cultural differences. additionally, participants discussed the issue of resource allocation within the framework of transparency, especially when preferential treatment is given to the most powerful community members as opposed to the most vulnerable. the african meeting participants affirmed the importance of providing resources to the young, but noted important differences in perspectives among countries. many african societies give higher status to the elderly than to other age groups. with a life expectancy for some african countries in the s and even s, the proportion of the population composed of young children is much higher than in other countries. thus, in african countries, a preference of allocating scarce resources to children would leave little resources for other segments of the population. generally, african countries are much more rural than are countries of other continents, making access to villages difficult, whether by road, telephone, or internet. although meeting attendees did not feel that rural or urban habitation should be a criterion for allocation of resources, they anticipated that logistical challenges would make it so. these concerns are dwarfed, however, by the likelihood that resources such as antivirals and vaccine will be far scarcer in african countries than elsewhere because of the continent's dual challenge of weak economies coupled with the number of other endemic health challenges, such as malaria and hiv/ aids. with few resources at hand, the ethical imperative to respond to pandemic influenza may fall below that of addressing hyperendemic fatal diseases. each of the countries represented in the asian meeting had a pandemic flu preparedness plan that addressed allocation issues and maintained a national stockpile of antiviral drugs. in most cases, biological vulnerability determined priority; thus, the very young or very old, pregnant women, and immunecompromised individuals tended to be prioritized to receive antiviral drugs. however, as asian cultures exhibit more hierarchy than those in the west, more honor is accorded to the elderly, senior staff, royalty, and public service personnel in asian cultures. in addition, it is expected that relatives and friends of the powerful will be unofficially prioritized to receive limited resources, without that being considered unethical. indeed, in many asian contexts, such prioritization is viewed as a social obligation (eg, a health worker would consider offering antivirals from the limited supply to a senior official before offering the resources to a person in one of the official priority groups). nevertheless, participants expressed disapproval of officials who abuse their power and demand or extort limited resources for themselves. one participant described a shortage of n face masks (masks that can filter at least % of particles from the air) during the sars epidemic. although some people were willing to pay twice the regular price for a n mask, yielding to this demand would in effect favor protection for the rich over the poor. the participants felt the government had a duty to enforce price controls in order to ensure an adequate supply. as an example of enforcing price controls, one government instituted licensing for antiretroviral distribution to put a ceiling on the costs of the medications. some of the asian perspectives on ethical distribution differed by religion. an appeal to buddhist beliefs stated a priority for those who are most severely ill, and the young making sacrifices for their elders. a priority for women and children was expressed with reference to catholic values. when a choice must be made between a mother and her child, participants at the asian meeting felt that catholic values would typically give preference to the mother. some asian nations include island archipelagoes. it will be difficult for populations living on minor remote islands to access medical services and resources during a pandemic. the participants questioned whether their country plans address the challenges that certain geographical conditions may place on the equitable distribution of resources. many participants of the latin american meeting thought that individual rights were paramount and that during a pandemic a clear communication plan that includes community input into the process for drug allocation would help avoid panic. they emphasized the importance of including all sectors of society, including the private sectors, migrants, and minorities in public health decision-making process. issues such as discrimination and stigmatization of certain sectors of the population must be addressed before an emergency situation arises. meeting participants stressed that emergency plans should take into account the diversity of population, must be transparent, and favor equal distribution of resources. at the eastern mediterranean meeting, participants discussed the need to evaluate "what is good for you versus what is good for others. " this included discussing ethical challenges associated with distribution of scarce resources. questions that were explored included: which group of people should be vaccinated first? who will make decisions about distribution? one theme that was identified from this discussion was the importance of prioritizing healthcare workers for access to limited resources, including medical and psychological care and other social benefits, should they become sick during an emergency. the use of social distancing to limit transmission was widely accepted as an important tool in a pandemic influenza response, but participants warned of the many factors and challenges that complicate this traditional public health measure. these include socio-economic factors (eg, densely populated settings), and cultural factors (eg, family duty, funeral rituals). participants in the african meeting agreed with the social distancing principles described in the who document, including making the measures voluntary to the greatest extent possible; ensuring "safe, habitable, and humane conditions of confinement including the provision of basic necessities (food, water, clothing, medical care, etc)"; and employment protection for workers who comply with social distancing measures against the wishes of their employers. participants stressed that isolation and quarantine measures will be more difficult to enforce in rural compared to urban areas in africa due to the isolated geography of some rural areas and the lack of healthcare workers and security officials. however, participants noted that these public health measures have been successfully employed in rural areas in prior epidemics in africa. densely populated urban slums were also noted to present a challenge to social distancing. in a typical slum dwelling, people occupy all available sleeping space at night in small and poorly ventilated homes. there is no separate space available for isolation or quarantine. the same applies in some refugee camps. in such densely populated settings, the lack of freedom of movement may lead to near-certainty of transmission. neighboring communities will be tempted to protect themselves by fencing off the slums or forcibly preventing the exit of slum residents. there was also concern among the participants that some african countries would rely heavily on military personnel to impose order, potentially with unnecessary force. participants in the asian meeting also noted challenges associated with the use of social distancing measures. duty to family is a major theme of confucian philosophy. in some asian countries, it is a tradition for friends and relatives to visit and even stay with a hospitalized person. in many instances, exhortations to family and friends about the serious nature of isolation are no match for the force of tradition: some find a way in and out of the isolation wards. due to the lack of resources, isolation wards do not have security guards, and nursing staff are not able to add policing to their already heavy workload. a common concern reported by participants at the asian meeting was the risk of stigmatization of patients and family members who were placed in isolation and quarantine. one of the participants reported that during the sars outbreak, an entire village was stigmatized because it was home to one of the cases. anybody known to have come from the village was avoided by others. workers from the village were not admitted to their place of employment outside the village. similarly, students were kept out of their schools. when the village was eventually quarantined, people feared delivering food and supplies. the stigma remained long after the epidemic subsided and the quarantine was lifted. high rates of poverty also pose a challenge for use of social distancing measures. it is difficult for patients to remain in isolation wards or for potentially exposed individuals to remain quarantined for long period of time unless compensation can be offered for lost wages. participants at the latin american and eastern mediterranean meetings reflected on the long history of human rights abuses in their countries. this made them more likely to view use of social distancing measures as something that should be considered with great caution. some even viewed these measures as human rights violations. obligations to and of healthcare workers healthcare workers have multiple obligations, including obligations to their patients, to their employers, to their governments, to themselves, and to their families. participants at all meetings understood that healthcare workers cannot completely sacrifice their and their family members' health and well-being as they fulfill their public health duties during an emergency response. participants at the african meeting felt that healthcare workers have the right to stop working if they feel they are not wellprotected. factors discussed included the challenges related to the displacement of health workers during post-election conflict, traditional or cultural practices that may increase the risk of disease spread (eg, hugging or handshaking), and conflicts between senior officials and frontline healthcare workers regarding access to resources. they felt that frontline health workers should have first priority. a complicating factor in many african countries is the presence of large numbers of health-care-related ngos from a variety of countries. what obligations would they have in a pandemic? if the workers or the organizations were to leave the country to attend to the needs of their home country or their families, the african country could lose a sizable proportion of its health workforce. and yet host governments have little authority to demand their assistance. socio-economic factors were predominant in stories told by participants at the asian meeting. for example, during sars outbreak, some private hospitals in one country were only admitting patients who could pay, while some suspected patients did not go to hospitals because they could not pay the inpatient care that could exceed $ per day in a country where per capita annual income is less than $ . some countries reported lack of personal protective equipment, such as face masks, for healthcare workers; or differences in the degree of protection offered according to position (eg, physicians offered more protection than nurses). participants reported that some healthcare workers refused to treat suspected cases, because either they did not have protective equipment and/ or because they were concerned for their own safety and the safety of their loved ones to whom they would return after work. the participants agreed that healthcare facilities and governments had an ethical obligation to adequately and equitably provide personal protective equipment to their employees. in addition, participants felt that education of the employees about transmission control and, in some instances, additional incentives such as hazard pay, can help overcome the hesitancy of healthcare workers to remain on duty during a pandemic surge in cases. participants at the latin american and eastern mediterranean meetings also discussed the roles of healthcare workers during influenza pandemic. participants at both meetings recognized the important responsibilities healthcare workers have to treat patients regardless of the risk to themselves, but also noted that governments have responsibilities to protect healthcare workers. some participants believed that healthcare workers have the right to refuse treatment to patients if the provider fears exposing their own family and that society has an obligation to compensate their families if they die while treating patients. other participants felt that doctors do not have the right to refuse treatment because of their oaths and duties as physicians. international collaboration international collaboration is complicated by many factors, including disparities in resources, political differences, ethnic tension, and distrust. participants, however, agreed that during a pandemic, collaboration is critical, because diseases respect no boundary. participants pointed out that no country, developed or undeveloped, has eliminated poverty and the underlying causes of ill-health, such as lower literacy among the poor and less knowledge about disease prevention. the prevalence of poverty affects not only individuals, but institutions and systems. because of the interdependence of nations, participants thought that it is in the best interest of resource rich countries to help build the capacity of poorer countries to conduct surveillance and disease control. participants in the african meeting stressed that the ability of a developing country to conduct thorough and accurate surveillance depends in large part on the assistance of developed countries in building and maintaining basic public health infrastructure well before a pandemic occurs. moreover, by its very nature, surveillance is an ongoing process, not one that can be initiated in the face of an emergency response and then terminated when things return to normal. in emergencies, international scientists may temporarily fill some personnel gaps. participants observed, however, that some international scientists providing technical assistance during an emergency seem more interested in research than in helping to control the disease outbreak. in some cases, they even diverted resources, such as healthcare workers, that could have been used for disease control. lack of wellequipped laboratories in many african countries has resulted in the transfer of human biological specimens to distant laboratories, sometimes delaying diagnosis and intervention. some surveillance resources are provided by donor nations for specific purposes such as measles eradication. strict accounting rules may prevent the shift of those resources to other purposes, even in the face of a major global threat. the asian meeting participants also expressed concern about specimen sharing. during outbreaks of sars and h n influenza, for example, china shared its specimens with countries around the world for research and vaccine development. during the outbreak of h n in , who noted that countries shared specimens. the asian participants noted that collaboration and communication about disease transmission requires a transparency that can be at odds with the cultural value of 'protecting honor' and 'avoiding being shamed' that is common in asia and elsewhere. reporting an outbreak to other countries can be perceived as admitting inadequate disease control and asking for help from another country may be viewed as a sign of weakness. this is complicated by often pre-existing disputes between neighboring countries. moreover, while helping others is also an important asian cultural value, offering help when a country has not asked for it may be regarded as meddling with the internal affairs of that country. moreover, two asian countries who conducted a joint outbreak investigation exercise observed that multilateral coordination can be time-consuming in ways that hinder a speedy and effective response. participants at the latin american meeting believed that it is important to clarify and disseminate guidelines for pandemic preparation and response, including those produced by who. dissemination of pertinent information and guidelines between countries was considered as an obligation countries have to one another. some noted that although wide disparity exists among latin american countries, there is a great deal of solidarity, which facilitates cross-border collaboration, such as seen in the collaboration between haiti and the dominican republic during the haiti earthquake and resulting cholera epidemic in . participants at the eastern mediterranean meeting noted that countries are sometimes reluctant to collaborate because of the political and resource differences and other disparities between countries in the region. however, they agreed that plans for responding to an influenza pandemic should be shared among countries so that countries will be familiar with neighboring countries' plans. participants believed that country or even regional plans are too broad and more specific sub-regional plans should be developed and implemented. although the ethical concerns raised by participants from these four distinct regions (africa, asia, latin american, and the eastern mediterranean) describe important issues that can shape responses to an international pandemic, the similarities of the perspectives and the concerns were notable. participants reaffirmed the importance of the five key ethical issues framed by who (ie, transparency and public engagement, allocation of resources, social distancing, obligations to and of healthcare workers, and international collaboration). participant feedback can be summarized as followed: • the procedural values of transparency and inclusiveness are widely accepted and crucial for ethical decisionmaking. • no "one size fits all" approach to allocating resources can address the variety of economic, cultural and other contextual factors that must be taken into account, but engaging with communities can help both to discover these factors and to build support for public health recommendations. • although meeting participants acknowledged the importance of social distancing as a tool to limit disease transmission, they also recognized the difficulties associated with this measure. • healthcare workers often have competing obligations that can compromise their ability to fulfill public health duties during an emergency response. government has a responsibility to assist them in doing their job by providing appropriate training and equipment. • although international collaboration may be difficult, a focus on procedural ethics (ie, procedures that ensure transparency, consistency, inclusiveness, and a fair hearing of concerns in a deliberative format) make collaboration possible in efforts to combat global health threats. the discussions from the meetings offer perspectives on how countries can collaborate in the control of international pandemics while respecting different cultural values. although we initially were concerned that cultural differences could seriously impede international collaborations, we believed that anticipatory awareness of value differences would help prevent them from becoming potential stumbling blocks. given this outlook, the meeting organizers were poised to highlight cultural differences. indeed, the meeting exposed numerous cultural differences; eg, people in asian countries more readily defer decision-making to government officials, elders, or other authority figures. many of the differences that surfaced during the meetings reflected differences in how decisions are reached in the context of a country's political arrangements. moreover, as the discussion of resource allocation illustrated, differences in local contexts and traditions necessarily will play a role in how interventions will be implemented. nevertheless, the similarities in perspectives between countries challenged our initial expectation that cultural differences would seriously impede if not prevent collaboration. attempts to change traditional cultural practices frequently fail or result in unintended consequences. however, addressing procedural ethics according to established international norms can assist with overcoming cultural differences within the context of global disease pandemic, political organization or local context. for example, the complicated ritual washing of bodies became a contentious issue in the - ebola response, because of its role in facilitating the spread of ebola virus. culturally, this practice was considered an essential part of preparing the dead for the after-life. public health and government workers contemplating halting or altering ritual practices require great cultural sensitivity and finesse in presenting alternatives that are perceived as fair and acceptable to a community already suffering from irreplaceable loss of their loved ones. the recent who ethics workgroup on ebola again illustrates the importance of a focus on procedural ethics. the workgroup included, along with ethicists and subject matter experts on ebola, representatives from the three west african countries hit hardest by the ebola virus. in relatively short order, the workgroup came to agreement on prominent ethical issues, such as the use of promising experimental drugs against ebola virus, the need to conduct research on these drugs, and the importance of informed consent even during a public health emergency. their success suggests that, when a fair process is established that includes the voices of those affected by the outbreak, a pandemic involving a deadly disease can bring countries rapidly together around the shared value of health, rather than divide them on the basis of cultural differences. perhaps the consensus regarding the importance of combating a pandemic health threat was to be expected, given that cdc or its partners such as tephinet sponsored and coordinated all four meetings, and, more importantly, the who ethics guidance framed the discussions of ethics topics. perhaps the participants consciously or subconsciously stated what they thought the sponsors wanted to hear. in addition, as many of the participants were public health officials, they brought with them a shared commitment to addressing health concerns. it is possible that the input of these health professionals, more numerous and vocal than other participants, explains the observed continuity around health-related matters. however, these conjectures do not seem compelling. cdc's sponsorship and the framing of discussion around the who's topics did not of themselves preclude major differences from surfacing within any particular topic. it also seems highly unlikely that the majority of differences were to be found outside of those ethics topics discussed at the meeting. the same who framework that oriented the participants to these topics also oriented them to the theme of cultural differences. moreover, the exercises, discussions, and responses were open ended and varied rather than being highly directive. it also seems improbable that participants were merely telling us what we wanted to hear and held back from expressing profound differences when the purpose of the meetings was precisely to explore cultural differences. a simpler and more compelling explanation lies in a crosscultural continuity regarding the importance of combating the health threats that would result from a pandemic event. this continuity should come as no surprise. human rights advocates, for example, deem health so fundamental to human flourishing that they consider it a basic human right. [ ] [ ] [ ] [ ] [ ] the "right of everyone to the enjoyment of the highest attainable standard of physical and mental health. " is encapsulated in article of the international covenant on economic, social, and cultural rights (cescr), a covenant which out of countries have thus far ratified. , similarly, the capability approach maintains that the freedom to achieve well-being is a primary human capability that creates the opportunity for people to realize other capabilities they value. campbell describes health as a liberation or freedom not only from pain or illness, but also as a freedom that allows a person to "create, inhabit a space, to simply live, and share the world around us. " for campbell, the concept of health lies in this freedom. he further believes that the meaning of health reflects personal values and beliefs that are closely linked to the local community and socio-cultural group. health in this view and as a matter of common human understanding is seen as a gateway, if not precondition, for developing other human functions and capabilities. it is a matter, then, not only of ethical theory but also of practical human life that pandemics, which pose existential threats to health, could be expected to elicit similar responses across cultures. there are a number of limitations associated with this manuscript. the manuscript reflects what we found of most interest in the reports, notes, and stories generated from the four regional meetings. it does not provide a complete reporting of the meeting proceedings; rather, it focuses on the parts of the discussion that were related to the key ethical challenges identified in the who ethical framework document. the meetings were meant to initiate an international dialogue about how ethical considerations can be incorporated into pandemic influenza preparedness among members of the field epidemiology training programs, public health officials, policy-makers, scientists, ethicists, religious leaders, and representatives of international aid and health organizations. the meetings were not part of a research study meant to develop new or generalizable knowledge. participants were not recruited in a systematic fashion. cdc relied on local partners to identify and nominate participants to attend the regional meetings. meeting agendas, sessions, and structures were tailored to the local interests and circumstances. although participants were oriented to the who ethics framework at the beginning of each meeting, discussions were not always focused on the same issues. this may explain the lack of consistency in the amount and depth of the discussions on the key ethical challenges identified in the who document. if the analysis and explanations above are sound, then it indicates that cultural differences need not pose a serious challenge for collaboration between countries in addressing an international pandemic. likewise, substantive ethical differences need not pose a serious impediment to pandemic preparedness efforts especially if more attention is paid to procedural ethics, that is, to procedures that ensure transparency, consistency, inclusiveness, and a fair hearing of concerns in a deliberative format. if any lesson is learned from past pandemics, it is that each one informs our response to the next. likewise, the ethical issues raised by past public health emergencies should serve to better prepare ourselves to effectively respond to the next emergency. the same applies to the discussions generated by the regional meetings described in this document. they affirm the notion that, cultural differences notwithstanding, people and countries will come together to combat the health threat a pandemic influenza poses to all, when fair procedures are established that give those affected a seat at the table and a voice. pandemic flu history. department of health and human services (flu.gov) website h n . department of health and human services (flu.gov) website lessons from previous influenza pandemics and from the mexican response to the current influenza pandemic h n . department of health and human services (flu.gov) website influenza epidemics and pandemics avian influenza virus h n : a review of its history and information regarding its potential to cause the next pandemic influenza viruses and the evolution of avian influenza virus h n avian influenza: the next pandemic? disease-a-month h n avian influenza: timeline of major events - january. world health organization website severe acute respiratory syndrome h n virus transmission and outbreaks update: severe respiratory illness associated with middle east respiratory syndrome coronavirus (mers-cov) -worldwide avian influenza a (h n ) virus. centers for disease control and prevention website stockpiling antiviral drugs for pandemic influenza: the key ethical principles. prepared by the ethics subcommittee of the advisory committee to the director ethical considerations for decision-making regarding allocation of mechanical ventilators during a severe influenza pandemic or other public health emergency. prepared by the ventilator document workgroup, ethics subcommittee of the advisory committee to the director identifying prioritization criteria to supplement critical care triage protocols for the allocation of ventilators during a pandemic influenza public engagement on ethical principles in allocating scarce resources during an influenza pandemic ethical considerations in developing a public health response to pandemic influenza. world health organization website ethical guidelines in pandemic influenza ethical guidelines in pandemic influenza: recommendations of the ethics subcommittee of the advisory committee of the director ethics and pandemic preparedness: the importance of cross-jurisdictional and cross-cultural perspectives ethical reasoning in pandemic preparedness plans: southeast asia and the western pacific influenza pandemic preparedness: legal and ethical dimensions kayman h, ablorh-odjidja a. revisiting public health preparedness: incorporating social justice principles into pandemic preparedness planning for influenza joint massachusetts department of public health-harvard altered standards of care working group on pandemics and the duty to care: whose duty? who cares facing the challenges of influenza in healthcare settings: the ethical rationale for mandatory seasonal influenza vaccination and its implications for future pandemics a matrix for ethical decision-making in a pandemic. the oregon tool for emergency preparedness pandemic influenza preparedness: an ethical framework to guide decisionmaking an ethics framework for public health and avian influenza pandemic preparedness why china's sars legacy may give it an edge against ebola pandemic (h n ) -update . world health organization website ethical challenges posed by the ebola virus epidemic in west africa ethical issues related to study design for trials on therapeutics for ebola virus disease. who ethics working group meeting report medicine and public health, ethics and human rights towards the development of a human rights impact assessment for the formulation and evaluation of public health policies the right to health in international human rights law what are health and human rights? what is a human-rights based approach to health and does it matter? health hum rights social and cultural rights status of ratification: international covenant on economic, social and cultural rights health as liberation: medicine, theology, and the quest for justice global health as a field of power relations: a response to recent commentaries ebola: the ethics of thinking ahead we acknowledge the invaluable contributions of the following individuals and organizations in organizing the regional meetings, developing meeting reports and summaries, from which this manuscript was based. we especially appreciate the work of mark white (cdc retired) who conceptualized, designed, collected, and analyzed data, and obtained funding and coordinated the regional meetings with external partners. in no particular order, we also would like to acknowledge the contributions of maria consorcia lim-quizon, david mukanga, fred wabwire-mangen, joseph ochieng, patrick nguku, rebecca babirye, dominic thomas, anant bhan, goldie macdonald, andreas reis (who), afenet, emphnet, safetynet, and tephinet. the findings and conclusions in this paper are those of the authors and do not necessarily represent the official position of the centers for disease control and prevention (cdc), the university of north carolina, chapel hill, nc, usa or tephinet at the task force for global health. all coauthors were involved in reviewing reports, stories, summaries, and notes from the meetings described in the manuscript. funding was provided by the united states agency for international development and cdc to support the four regional meetings described in the manuscript. funding was used for travel-related expenses of all participants, including the co-authors of this paper, to participate in one or more of the meetings. not applicable. this manuscript was based on analysis of reports and documentations generated from four cdc-sponsored regional meetings. the meetings were considered routine public health practice and not research per se. key: cord- - gpije d authors: netherton, christopher; moffat, katy; brooks, elizabeth; wileman, thomas title: a guide to viral inclusions, membrane rearrangements, factories, and viroplasm produced during virus replication date: - - journal: adv virus res doi: . /s - ( ) - sha: doc_id: cord_uid: gpije d virus replication can cause extensive rearrangement of host cell cytoskeletal and membrane compartments leading to the “cytopathic effect” that has been the hallmark of virus infection in tissue culture for many years. recent studies are beginning to redefine these signs of viral infection in terms of specific effects of viruses on cellular processes. in this chapter, these concepts have been illustrated by describing the replication sites produced by many different viruses. in many cases, the cellular rearrangements caused during virus infection lead to the construction of sophisticated platforms in the cell that concentrate replicase proteins, virus genomes, and host proteins required for replication, and thereby increase the efficiency of replication. interestingly, these same structures, called virus factories, virus inclusions, or virosomes, can recruit host components that are associated with cellular defences against infection and cell stress. it is possible that cellular defence pathways can be subverted by viruses to generate sites of replication. the recruitment of cellular membranes and cytoskeleton to generate virus replication sites can also benefit viruses in other ways. disruption of cellular membranes can, for example, slow the transport of immunomodulatory proteins to the surface of infected cells and protect against innate and acquired immune responses, and rearrangements to cytoskeleton can facilitate virus release. viruses are obligate intracellular parasites. unlike their hosts, they cannot replicate by growth or division but use their genomes to redirect host cell processes to produce all the components needed to make new viruses. virus replication and assembly are often confined within specific intracellular compartments called virus factories, viroplasm, or viral inclusions. these are thought to provide a physical platform to concentrate new genomes and proteins involved in replication and assembly, and this is likely to increase the efficiency of virus production. the formation of specialized sites of replication can involve extensive reorganization of cellular cytoskeleton and membrane compartments. this can lead to cell rounding and swelling and a ''cytopathic effect'' that has been documented for many years (reissig et al., ; robbins et al., ) . recent advances in microscopy, such as live cell imaging and tomography, combined with the power of reverse genetics, are now allowing the cytopathic effect to be redefined in terms of specific effects of viral proteins on specific cellular processes rather than an overwhelming assault on the cell in preparation for cell lysis. there is considerable interest in understanding how virus infection leads to the large changes in cellular organization required to produce complex replication sites. in the simplest model, virus replication sites would form passively through self-association of viral components and exclusion of host organelles. viruses, however, require a considerable number of host proteins to facilitate replication, and there is increasing evidence that these are specifically transported to sites of replication. host proteins may move to replication sites because they are actively recruited by binding to specific viral proteins. alternatively, viruses may transport viral and host material to replication sites by subverting host defences against infection [reviewed by kirkegaard et al. ( ) and wileman ( ) ]. the large scale changes in cellular membrane and cytoskeletal organization, which occur during the formation of replication sites, can offer further benefit to viruses. rearrangement of the cytoskeleton can, for example, facilitate virus release, and the block in the secretory pathway seen during infection with positive-stranded rna viruses can reduce release of inflammatory mediators and protect against innate and acquired immune responses. this is a broad subject of considerable interest to virologists and cell biologists, and we have benefited from excellent reviews that have been published (mackenzie, ; novoa et al., ) . in writing this chapter, we have concentrated on describing sites of virus replication in the context of the cell in which its replication takes place. we have illustrated these concepts with reference to replication sites produced by many different viruses and, where possible, described how virus replication impacts on the functioning of the host cell. virus replication sites have been studied for many years and have evolved their own terminology. early studies of poxvirus replication (dales and siminovitch, ; morgan et al., ) describe electron-dense aggregates and amorphous material induced early during infection called viroplasm. viroplasm has also been used to describe similar structures induced during infection with poliovirus (dales et al., a) . viroplasm is often concentrated within perinuclear areas that exclude host organelles. viroplasm is thought to indicate sites of virus replication, and concentrations of viroplasm have been called virosomes, or virus factories, to reflect an organelle involved in virus production. virus infection also produces inclusion bodies. as a working definition, these can be considered to form later during infection. they can form virus factories once virus production has peaked, and/or at other sites in the cell they probably arise from an accumulation of viral proteins that do not become incorporated into viruses. the positive-stranded rna viruses encode nonstructural proteins (nsp) that cause proliferation and modification of membranes of the host secretory pathway. the membranes are thought to provide a physical framework or ''replication complex'' that concentrates the cellular and viral components required for virus replication (bienz et al., ; egger et al., ; froshauer et al., ; gazina et al., ; magliano et al., ; schlegel et al., ; van der meer et al., ) . assembly of the replicase on membranes, rather than the cytosol, may also help viruses evade host defence pathways that monitor cells for double-stranded rna (dsrna) intermediates indicative of virus replication. the replicase complexes of all the positive-stranded rna viruses contain an rna-dependent rna polymerase (rdrp), a protein with ntpase and helicase activity, and in many cases a methyl transferase to cap viral rna. these proteins are generated from the viral polyproteins by viral proteases, and are then targeted to membranes in ways that differ depending on virus family (fig. ). the replicase proteins of positive-stranded rna viruses are directed to membranes by nsp with membrane-targeting information. (a) picornavirus. the replication complex contains d, the rdrp (red), and c which has ntpase and helicase motifs (purple). the d polymerases do not have membrane-targeting information but are synthesized as a abcd precursor. abcd is processed to ab by the c protease (red triangle) and a hydrophobic domain in a targets ab to the cytoplasmic face of er membranes. ab binds directly to d and this targets the polymerase to the replication complex. the replication complex also requires bc and c proteins that are targeted to membranes via their own hydrophobic domains (black lines). (b) flavivirues. the replication complex is encoded at the c-terminus of a polyprotein that is processed by the ns protease (red triangle). ns b is the rna-dependent polymerase (red), and ns acts as helicase (purple). ns b is a polytopic membrane protein inserted into the er cotranslationally. ns a, a, and b have hydrophobic domains (gray lines) that allow posttranslational insertion into the cytoplasmic face of the er membrane. ns is recruited into the complex by associating with ns a. (c) alphavirus. the nsp polyprotein is processed by a protease activity in the c-terminus of p (red triangle). the polyprotein is anchored to the cytoplasmic face of endosome and lysosome membranes membranes that lie between the er and the golgi apparatus called the er-golgi intermediate compartment (ergic), or tubulovesicular structures, and specific fusion with ergic membranes is determined by a complex of proteins called transport protein particle (trapp ). trapp proteins tether the vesicles on ergic and golgi membranes, allowing interactions between vesicle and target snare (soluble n-ethylmaleimidesensitive factor attachment protein receptor) proteins to facilitate membrane fusion. the snare interactions are controlled by vesicle-specific small gtpases called rab proteins (fig. ) . further sorting events in the ergic and early golgi involve a second complex of coat proteins called copi. the copi complex contains seven proteins (a, b, b , g, d, e, and z cop proteins), which generate vesicles that take proteins from the ergic and golgi apparatus back to the er through a retrieval pathway (fig. ) . the copi proteins are recruited from the cytosol by the arf -gtpase. activation of arf requires binding to gtp and is facilitated by gtp exchange protein, arf-gef. arf -gtp inititates coat assembly while hydrolysis of gtp by arf leads to coat disassembly. this disassembly is stimulated by an arf -gtp-activating protein (arf-gap) that promotes gtp hydrolysis by arf . a possible role for arf in the generation of vesicles during picornavirus replication has been the focus of much work following the observation that poliovirus replication is blocked by brefeldin-a (bfa), a drug that inhibits the recruitment of arf onto membranes (maynell et al., ) . membrane vesicles are also produced in cells in response to starvation. this pathway, known as autophagy, is used as a part of a quality control system that removes long-lived proteins and damaged organelles from the cytoplasm and has been shown to provide a defence against intracellular pathogens (deretic, ; kirkegaard et al., ; levine and klionsky, ; shintani and klionsky, ) . the origins of the membranes formed during autophagy are unclear but may be derived from the er (reggiori and klionsky, ) . autophagy is suppressed by the target of rapamycin (tor) kinase and is activated by conditions that lead to inactivation of tor. this leads to the production of membrane crescents in the cytoplasm, called isolation membranes, which mature into doublemembraned vesicles of -to -nm diameter called autophagosomes. this maturation engulfs small quantities of cytoplasm, and any organelles or pathogens present at sites of autophagy become trapped within autophagosomes. the autophagosomes ultimately fuse with lysosomes resulting in degradation of their content. autophagosomes are of interest because infection of cells with picornaviruses and coronaviruses (covs) can generate double-membraned vesicles that may be related to autophagosomes. in addition to supplying membrane and proteins to the secretory pathway, the er acts as a major site of lipid synthesis. as a consequence, the er contains a large quantity of membrane, and this is organized into a complex reticulum made from tubular and lamella structures (borgese et al., ) . the smooth er increases in response to a buildup of er membrane proteins and can be organized into lamellae or concentric whorls called organized smooth er (oser). structures similar to oser are also seen during virus replication. b. picornavirus replication induces numerous membrane vesicles picornaviruses are nonenveloped positive-stranded rna viruses. the genome encodes a large polyprotein that is processed to generate capsid proteins from the p region and nonstructural replicase proteins from the p and p regions. picornavirus d contains the rdrp, while c has ntpase and helicase motifs. the d polymerase does not have membrane-targeting information but is synthesized as a abcd precursor. abcd is processed to ab by the c protease, and a hydrophobic domain in a targets ab to the cytoplasmic face of the er. d binds directly to ab, and this targets the polymerase to the replication complex. the d polymerase of poliovirus is believed to self-assemble into a large ordered array on membranes, which is critical for binding rna and rna elongation (lyle et al., ) . the replication complex also requires bc and c proteins that are targeted to membranes via their own hydrop hobic dom ains ( fig. a ). the accumulation of large numbers of densely packed membrane vesicles in the cytoplasm is characteristic of a picornavirus infection (bienz et al., (bienz et al., , cho et al., ; dales et al., a; schlegel et al., ; stuart and fogh, ; suhy et al., ) . studies have suggested that vesicles induced by poliovirus are derived from the er, either from copii-coated vesicles or from er-derived autophagic double-membraned vacuoles (bienz et al., ; jackson et al., ; rust et al., ; schlegel et al., ; suhy et al., ) . however, the detection of er, golgi, and lysosomal markers in membranes induced at later stages of infection by poliovirus suggests that more than one organelle may contribute membranes to the replication complex (schlegel et al., ) . in interpreting these studies, it is important to consider if the vesicles observed are involved in replication, or if they represent a bystander response to virus infection. evidence for a role of specific membranes in replication is provided by the presence of replicase proteins, or better still dsrna or negative-stranded intermediate viral rna (egger and bienz, ) . examination of cells infected with poliovirus for the first appearance of negative-stranded rna suggests that this initial stage of replication starts on the er. this is consistent with high-resolution immunofluorescence microscopy (rust et al., ) showing the poliovirus b protein associated with eres containing the sec -sec p proteins of the copii complex. these sites exclude resident er proteins, suggesting colocalization of b with copii-coated transport vesicles. replication complexes containing negative-stranded rna then move on microtubules to a perinuclear area to initiate synthesis of positive-stranded rna (egger and bienz, ) . membrane rearrangements have been studied by expressing individual, or combinations, of picornavirus proteins in cells. most of this work has involved studies of poliovirus proteins, and membrane rearrangements are reported for the b, c, bc, a, and ab proteins. poliovirus b causes fragmentation of the golgi complex (sandoval and carrasco, ) . the bc and c proteins lead to vesiculation and tubulation and sometimes myelin-like swirls of er-derived membranes (aldabe et al., ; cho et al., ) . similar structures are induced by c and bc of hepatitis a virus (teterina et al., ) . expression of the poliovirus a protein causes swelling of er cisternae and the disappearance of vesicles budding from the er, while the ab protein also induces myelin-like swirls of er (egger et al., ) . the membrane rearrangements induced by expression of single proteins do not, however, mirror those observed in infected cells, and since myelin-like modifications to the er are also seen following overexpression of er proteins [reviewed by borgese et al. ( ) ], their relevance to viral replication is unclear. importantly for poliovirus, it is a combination of bc and a protein expression that induces membrane structures morphologically similar to those seen in infected cells (suhy et al., ) . gazina et al. ( ) have studied replication complexes formed by several different picornaviruses. encephalomyocarditis virus (emcv), parechovirus , and echovirus induce clustered vesicles containing dsrna in the perinuclear region of the cell. the precise nature of the vesicles varied with virus. parechovirus produced homogeneous vesicles of - nm, while membranes produced by emcv and echovirus were heterogeneous but more compact and associated with electron-dense material. differences for parechovirus have also been reported by krogerus et al. ( ) who suggest that replication may occur on membranes derived from the late golgi rather than early er and ergic compartments. all three viruses, however, cause loss of ribosomes from the er and lack of visible golgi apparatus. the copi coat protein b-cop was found to colocalize with echovirus replication complexes, but not with replication complexes produced by emcv, again suggesting that vesicles produced by different picornaviruses may differ. infection with foot-andmouth disease virus (fmdv) also results in loss of ribosomes from the er and an accumulation of heterogeneous vesicles to one side of the nucleus . high-pressure freezing can be used to increase the preservation of cellular ultrastructure during processing for electron microscopy. such analysis of cells infected with poliovirus shows that the vesicles have two membranes suggestive of autophagosomes ( jackson et al., ; suhy et al., ) . double-membraned structures containing electron-dense material, and possibly viruses, were also revealed by the early work on poliovirus (dales et al., a) . high-pressure freezing has been used to compare fmdv and bovine enterovirus (bev). bev produced heterogeneous membrane clusters similar to the rosettes described for poliovirus (egger et al., ) . many of the vesicle membranes have high electron density suggestive of double membranes and lie adjacent to accumulations of virus-like particles. clusters of fmd viruses were also associated with vesicles and electron-dense material, but there were fewer doublemembraned vesicles . immunofluorescence analysis of poliovirus vesicles shows colocalization of replicase protein a and autophagy marker lc , suggesting assembly of the replicase on autophagosomes. similar work suggesting the use of autophagosomes during replication of covs will be described below. for poliovirus, expression of a and bc, which produces vesicles similar to those seen in infected cells (suhy et al., ) , can induce autophagy (jackson et al., ) , and inhibition of autophagy reduces yields of extracellular virus. the results suggest that the autophagy pathway may facilitate the release of poliovirus from cells, and it will be interesting to see if this is true for other enteroviruses that are resistant to the low ph and proteases present in lysosomes and autophagosomes. evidence that different members of the picornavirus family vary in the way that they interact with host membranes is provided by studies of virus sensitivity to bfa. bfa completely inhibits poliovirus and echovirus replication (cuconati et al., ; gazina et al., ; irurzun et al., ; maynell et al., ) and partially inhibits parechovirus replication (gazina et al., ) but not other picornaviruses such as emcv (gazina et al., ) or fmdv o'donnell et al., ) . bfa prevents assembly of copi coats and this has generated considerable interest in understanding how copi and copii coats contribute to formation of the replication complex, and how bfa inhibits picornavirus replication. in cells infected with the highly bfa-sensitive virus echovirus , b-cop was recruited into the replication complex; in contrast, the replication complex formed by the bfa-resistant emcv did not contain b-cop. this correlation suggests that bfa-sensitive viruses may require copi coats for replication (gazina et al., ; mackenzie, ) . since copii coats are resistant to bfa (lippincott- schwartz et al., ; orci et al., ; , it is suggested that copii coats may provide the membranes for replication complexes formed by bfa-insensitive viruses. the observation that poliovirus replicase b protein is seen in eres containing copii proteins, but poliovirus is sensitive to bfa, can be reconciled if this association of b with eres is considered to be an early step in generation of membrane for the replication complex that precedes recruitment of copi coat proteins. this is supported by work showing the movement of poliovirus replication complexes containing negative-stranded rna from the er to perinuclear sites (egger and bienz, ) . direct evidence that copi coat proteins are required for picornavirus replication comes from studies of drosophila c virus (dcv). dcv is a positive-stranded rna dicistronic virus that is similar to poliovirus and replicates in a cytoplasmic compartment containing virus-induced membrane vesicles. a genome-wide rna silencing screen identified six (a, b, b , g, d, and z) of the seven copi coat proteins as essential for virus replication. furthermore, the formation of virus-induced vesicles required b-cop, but not copii protein, sec p. notably, small interfering rnas against a-cop, but not sec p, also slowed poliovirus replication (cherry et al., ) . the formation of copi-coated vesicles is regulated by the arf -gtpase. the observation that bfa inhibits the replication of enteroviruses such as poliovirus, and also inhibits the function of the arf -gtpase, provides a second link between virus replication and copi coats. arf proteins are regulated by arf-gefs that facilitate binding of gtp by removing gdp, and by arf-gaps that increase hydrolysis of gtp by arfs. arf -gefs are inhibited by bfa, and bfa therefore reduces levels of arf -gtp in cells. the gefs affected by picornavirus infection are golgi-associated bfaresistant protein (gbf ) and bfa-inhibited protein (big / ). work by belov et al. ( belov et al. ( , indicates that infection of cells with poliovirus increases intracellular arf-gtp levels fourfold, suggesting increased activity of arf -gefs or inhibition of arf -gap proteins. in the absence of virus, arf is concentrated in the golgi apparatus, but during infection with poliovirus arf staining fragments and colocalizes with replicase protein c. this suggests that infection leads to a redistribution of arf proteins from the golgi apparatus to the replication complex. the binding of arf proteins to membranes is dynamic, with arf-gdp being released from membranes following hydrolysis of gtp. cytosolic arf -gdp would redistribute naturally to membranes enriched for the arf -gefs that facilitate loading of new gtp. significantly, poliovirus infection causes enrichment of gefs in membranes containing replicase proteins, and this would provide a mechanism for increasing levels of arf -gtp at sites of virus replication. translation of poliovirus rna on membranes in vitro provides an alternative means of studying the role of arf proteins in virus replication. replication is inhibited by bfa and peptides that function as competitive inhibitors of arf (cuconati et al., ) , and for the most part, the assay mimics what is observed in infected cells. translation in vitro leads to recruitment of arf and arf but not arf (belov et al., ) onto membranes. suitable antibodies recognizing the er-associated arf were not available for these experiments, so it is not known if arf is also recruited to membranes during translation. membrane recruitment of arf proteins can be reconstituted by translation and expression of poliovirus a or cd. poliovirus proteins do not show intrinsic gef activity, but a and cd will induce association of gbf and big / , respectively, with membranes in vitro. this raises the possibility that recruitment of a and cd to the replication complex during infection targets arf-gef to virus-induced membranes, which in turn increases local levels of arf -gtp. this is thought to be necessary for replication because inhibition of arf -gef by bfa blocks replication, and replication can be rescued by overexpression of gbf (belov et al., ) . high levels of arf -gtp would also increase recruitment of copi proteins and be consistent with the work on dcv showing that copi proteins are required for replication and vesicle production (cherry et al., ) . a poliovirus a mutant with a serine insertion at position is unable to cause translocation of arf to membranes (belov et al., ) . poliovirus carrying the a mutation does not, however, show defects in replication, suggesting that arf -gef recruitment to membranes by a is not essential for replication. it is possible that during infection the defect in a is compensated for by cd. interestingly, a bfa-insensitive poliovirus with mutations in the c and a proteins (crotty et al., ) induces vesicles and dispersal of the golgi apparatus, which begs the questions, does this mutant use a different process for forming the replication complex, or do the mutations in a allow the proteins to compete with bfa for gbf recruitment? the role of arf proteins during coxsackievirus infection has also been studied. in common with poliovirus, coxsackieviruses are enteroviruses and their replication is inhibited by bfa. expression of coxsackievirus a causes loss of copii coats from eres, and an accumulation of a, copii and a model secreted protein in both the er, and tubular-vesicular post-er structures containing ergic marker proteins. these effects closely resemble the effects of adding bfa to cells, suggesting coxsackievirus a may affect the function of arf proteins. coxsackievirus a affects the regulation of arf proteins (wessels et al., b) . interestingly, the process differs to that described by belov et al. ( belov et al. ( , for poliovirus a translated in vitro. expression of coxsackievirus a in cells caused loss of copi and arf from membranes, and there was redistribution of big / and gbf from the golgi apparatus into the cytoplasm. this suggests that coxsackievirus a reduces, rather than enhances, levels of arf -gtp. coxsackievirus a also caused redistribution of arf -gap to punctate structures suggestive of the ergic. a block in arf -gef activity, combined with recruitment of arf -gap, would reduce the levels of arf-gtp and inhibit membrane recruitment of copi. wessels et al. ( a) examined the effects of the a proteins of other picornaviruses and found that only the a proteins of enteroviruses bound gefs. intriguingly, wessels' work contrasts with belov in that they found the interaction of a with gefs lead to a loss of arf proteins from membranes. why these differences are seen is, as yet, unknown but may be due to differences in cell type/methods used or differences in levels of a protein expression. poliovirus and coxsackievirus slow protein movement through the secretory pathway (doedens and kirkegaard, ; wessels et al., ) . expression of b, bc, and a individually were all able to slow secretion (cornell et al., ; doedens and kirkegaard, ; doedens et al., ; van kuppeveld et al., ; wessels et al., wessels et al., , a , but for both viruses the a protein was found to have the greatest impact on er-to-golgi transport. poliovirus infection, and the a protein expressed alone in cells, reduces surface expression of mhc class i, the tnf receptor, and secretion of b-ifn, il- , and il- (choe et al., ; deitz et al., ; dodd et al., ; neznanov et al., ) , and this may offer an immune evasion strategy to the picornaviruses. this is consistent with the observation that the ability of the coxsackievirus a protein to slow secretion may be important for virulence (wessels et al., b) and has led to studies of the mechanism of action of a in blocking er-to-golgi transport. deletion analysis has identified residues in the unstructured n-terminal region of poliovirus and coxsackievirus a as important for the block in host protein secretion (choe et al., ) . an n-terminal proline-rich region (particularly pro ) is important for coxsackievirus block in trafficking (wessels et al., ) . in poliovirus, lys appears important, and in the triple-proline motif (positions - ), only the pro is indispensable for inhibition of protein secretion (choe et al., ) . a serine insertion in a protein between thr and ser , creating the a- mutant virus (berstein and baltimore, ) , was found to abolish the er-to-golgi inhibition of protein trafficking but has little effect on virus replication or membrane rearrangements (dodd et al., ; doedens et al., ) . this important observation shows that the ability of a to inhibit protein secretion is separate from its role in membrane rearrangements and viral replication. there is continuing interest in understanding how picornavirus proteins block secretion. poliovirus a and cd, and coxsackievirus a, can interact with arf-gef, but the downstream events are unclear. the recruitment of arf-gef by poliovirus a and cd would increase recruitment of arf-gtp to membranes of the replication complex. this would increase recruitment of copi coat proteins into sites of virus replication and reduce the pool of copi proteins available to the ergic and golgi apparatus. alternatively, inhibition of arf-gef and recruitment of arf-gap onto ergic membranes by enterovirus a would decrease membrane association of arf-gtp and again reduce recruitment of copi onto ergic and golgi membranes. both mechanisms would reduce the formation of copi vesicles, and as seen for bfa, block secretion. poliovirus a also binds and inactivates l s , a component of the dynein-dynactin motor complex (kondratova et al., ) , which is required to move copiiderived vesicles from eres to the ergic. as seen for expression of a, mutant l s leads to disruption of the er-to-golgi traffic and reduction in plasma membrane receptors such as tnf receptor. it is possible that a may also slow er-to-golgi transport by binding l s . a. picornaviruses differ in the use of nonstructural proteins to block secretion the ability of a to inhibit er-to-golgi trafficking has not been conserved in all picornaviruses (choe et al., ; cornell et al., ; deitz et al., ; moffat et al., ) . for example fmdv infection leads to reduced surface expression of mhc class i (sanz-parra et al., ) , but the fmdv a protein does not inhibit er-to-golgi transport . a lack of inhibition of secretion has also been reported for a proteins of human rhinovirus, hepatitis a, theiler's virus, human enterovirus, and emcv (choe et al., ; wessels et al., a) . the a protein of human rhinovirus is unable to bind gbf , or inhibit copi recruitment to membranes, and this may explain its inability to slow secretion. importantly, studies on fmdv have shown that the bc protein, or a combination of the processed products, b and c, inhibits protein movement from the er to the golgi apparatus (moffat et al., , , and this may be similar for other picornaviruses with a proteins that do not block er-to-golgi transport. a lack of effect of fmdv a on secretion does not result from an inability to bind membranes. fmdv a is recovered from postnuclear membrane fractions, and when expressed alone in cells it colocalizes with resident er proteins. in common with a, picornavirus b, c, and bc proteins also contain membrane-binding sequences. sequence alignment of the b, c ( bc), and a proteins of different picornaviruses showed a high level of conservation between the c proteins, which contain an ntp-binding site and predicted helicase motifs (gorbalenya et al., ) but large variations in the sequences of the b and a proteins (choe et al., ; moffat et al., ) , and these may explain their different abilities to block secretion. the fmdv a protein is, for example, much longer than a of enteroviruses, such as poliovirus, and it does not contain the n-terminal sequences thought important for poliovirus a to block the secretory pathway. the b protein of fmdv also locates to er membranes but shows a more reticular pattern than the fmdv a protein and can be seen in punctate structures aligned along the er suggestive of eres (fig. ) . this is similar to the b of poliovirus that colocates with both figure subcellular location of foot-and-mouth disease nsp encoded in the p region of the fmdv genome. vero cells expressing fmdv b (top), bc (middle), or c (bottom) were fixed and permeabilized and processed for immunofluorescence. c and bc were located using antibodies specific for c ( f ) and b was located using an antibody raised against an epitope tag in b. cells were counterstained using antibodies against er luminal protein erp (top and middle panels), or copi protein b-cop (bottom). merged images are shown at higher magnification on the far left. see moffat et al. ( ) for more details. reprinted from moffat et al. ( ) with permission from american society for microbiology. sec p and sec p of the copii coat. as expected, fmdv c is also membrane associated. when expressed in cells, c produces faint er staining, but mainly locates to bright punctate structures in a perinuclear region close to b-cop, reminiscent of golgi staining. the b-cop staining is, however, fragmented suggesting dispersal of the golgi apparatus, and there is not complete colocalization since c structures negative for b-cop protein can also be seen (moffat et al., ) . a similar location of fmdv nsp within the area of the cell occupied by the golgi apparatus is seen in cells infected with fmdv, and again they do not colocalize with golgi markers . the bc protein of fmdv is also recovered in postnuclear membrane fractions, but when expressed in cells, bc staining differs from that seen for the processed products, b and c (fig. ) . fmdv bc locates to punctate cytoplasmic structures and larger structures surrounding the nucleus that contain er markers suggesting swelling of the er. bc shows partial overlap with luminal er markers but, unlike poliovirus bc, does not colocate with the copii marker sec p. the er markers also appeared punctate in cells expressing bc, suggesting disruption of the er . interestingly, coexpression of b and c blocks secretion within post-er compartments, similar to those containing c. the site of block therefore seems to be determined by the subcellular location of c (moffat et al., ) and is consistent with the observation that the block in the presence of b can be redirected to the er, if c is tethered to the er by an er retention sequence. sindbis virus (sbv) and semliki forest virus (sfv) are the best studied examples of alphavirus replication in mammalian cells [reviewed by salonen et al. ( ) ]. early electron microscopy studies showed that vesicular structures called cytopathic vacuoles between -and -nm diameter, accumulated in infected cells. the vacuoles contained -nm-diameter vesicles called spherules, many of which were aligned along the inside face of the vacuole and attached by a neck to the limiting membrane. the neck was often seen connected to an electron-dense matrix extending into the cytoplasm. the observation that the cytopathic vacuoles contained nsps required for rna replication, cofractionated with lysosomal enzymes, and could be labeled with endocytic markers (froshauer et al., ) , led to the conclusion that they are sites of viral replication derived from endosomes and lysosomes. in many cases, the vacuoles were also connected to the rough er by filaments and granular material containing the rna polymerase. alp havirus ns ps are syn thesized in the cytop lasm and bind to endosom es and lysos omes to generate a replication compl ex. the rep licase pro teins are syn thesized as a polyprote in (p ) . the p domai n is the rdrp wh ile p has ntpase and helicase activi ties, and p is the methytran sferase require d to cap rna ( fig. c) . the p poly protein locate s to endosome or lysosome membranes via an amphipathic peptide sequence in p (salonen et al., ) . at this stage the p polymerase is cleaved from the polyprotein and functions with the remaining p protein to generate negative-stranded rna. interestingly, once the p is processed to individual nsps, the polymerase preferentially produces positive-stranded rna. expression of individual nsps does not lead to the formation of a cytopathic vacuoles or spherules. formation of spherules requires interactions between nsp p , p , and p and the p polyprotein precursor complex (salonen et al., ) . rubella virus is a member of the togaviridae family within the alphavirus genus. cells infected with rubella virus also contain vacuoles containing spherules and these colocalize with lysosomal markers, suggesting use of lysosomes for replication. a fibrous material connects the vacuoles to the er (lee et al., ; magliano et al., ) , again suggesting strong similarities with sfv and sbv. members of the alphavirus superfamily share homologies between proteins required for rna replication, and this extends to plant viruses. alfalfa mosaic virus replicase proteins colocalize with the plant vacuole (van der heijden et al., ) , and turnip yellow mosaic virus uses the chloroplast outer envelope as a site for replication. replication of tobacco mosaic virus, a tobamovirus, is dependent on arabdopsis proteins tom and tom a that are integral membrane proteins of the tonoplast (hagiwara et al., ) . the tonoplast is a membrane compartment within plants that surrounds the vacuole/lysosome, suggesting plant alphaviruses also use the endosome/lysosome system as a site of replication. infection of plants with alphavirus-like superfamily viruses can also induce the formation of spherules (prod'homme et al., ) . there is evidence that tobacco mosaic virus also uses the er as a site of replication because the replicase enzyme and viral rna are located on the er of infected cells, and infection causes major changes in er morphology (reichel and beachy, ) , including er aggregation and formation of lamella structures. flock house virus replicates in spherules in the outer membrane of mitochondria. the rna polymerase (protein a) of flock house virus is the only protein required for rna replication and is targeted directly to the mitochondrial outer membrane by hydrophobic amino acids at the n-terminus. this sequence contains a mitochondrial localization signal and transmembrane domain that leaves the bulk of the protein exposed to the cytoplasm (miller and ahlquist, ) . brome mosaic virus replicates in yeast and has been studied extensively. the a and a replicase proteins are produced from separate viral rnas. the a protein contains a c-terminal helicase domain and an n-terminus required for rna capping. a is targeted to the cytoplasmic face of er membranes and recruits the a polymerase to the replication complex (schwartz et al., ) . importantly, replication of brome mosaic virus on the cytoplasmic face of the er in yeast induces membrane invaginations of nm that are very similar to the spherules produced in endosomes and lysosomes during alphavirus infection of mammalian cells. it has been suggested that the active formation of spherules to separate viral rna from host responses is analogous to the coordinated assembly of viral proteins, which leads to capsid assembly, genome packaging, and budding (ahlquist, ; schwartz et al., ) . the brome mosaic virus replication complex contains viral a and a pol proteins within spherules. expression of a alone produces a shell containing hundreds of copies of a on the inside of -nm spherules. in a capsid assembly model (schwartz et al., ) , vesicles of uniform size would arise if the a protein first made a planar lattice with hexameric symmetry on membranes and achieved curvature by localized rearrangement of a into pentamers. interestingly, the formation of spherules is dependent on the relative levels of a and a pol . when levels of a pol are high, the spherules are lost, and a and a pol assemble into flat lamella structures associated with the er (schwartz et al., ) . one explanation for a failure to achieve curvature is that high levels of a pol may interfere with this hexamer to pentamer transition. this is supported by the observation that when domains that allow association of a and a pol are deleted, the a pol is unable to alter the structure of spherules formed by a. the correct ratio of a and a pol is clearly important for replication complex assembly and may be maintained during infection through inhibition of translation initiation of the a rna. d. the flaviviridae replicate in vesicular packets and membraneous webs in the flaviviridae family, which includes the flavivirus, pestivirus, and hepacivirus genera, the rna genome encodes a polyprotein precursor that is cleaved by viral proteases to produce structural proteins from the n-terminal region. the replicase of the flaviviridae is made from nsps, ns a, ns b, ns b, and ns - a, found at the c-terminus. wi th the exce ption of the polytop ic ns b membr ane prote in, whic h is ins erted co transl ationall y into the er, the membr ane-an chored co mponent s of the compl ex are inserted into the cytopla smic face of the er after tran slation ( fig. b) . the ns b is the rdrp, and a c-termi nal stretch of hydrophobic amino acids directs ns b to the cytoplasmic face of the er (dubuisson et al., ; moradpour et al., ) . the ns protein has ntpase/helicase activity. ns is not a membrane protein but is recruited to the complex through association with membrane-anchored ns a. ns a is also membrane associated, and association is mediated via amino acids at the n-terminus that form an amphipathic a-helix (brass et al., ; elazar et al., ) . replication of flaviviruses (e.g., dengue, west nile, and yellow fever viruses) takes place in membrane invaginations. for historical reasons, these are called vesicular packets [reviewed in mackenzie ( ) ]. they are larger ( -to -nm diameter) than the -nm alphavirus spherules, and form from the limiting membrane of the trans-golgi network (tgn) (uchil and satchidanandam, ; westaway et al., b) . infection by kunjin virus leads to unique membrane structures thought to be derived from both the early and late secretory pathways. these include convoluted membranes and paracrystalline arrays derived from the rough er and ergic, and vesicle packets derived from the tgn (mackenzie et al., ; ng, ; roosendaal et al., ; westaway et al., b) . the detection of dsrna and viral nsps (ns , ns a, ns , and ns a) within the vesicle packets points strongly to this being the site of rna replication (mackenzie et al., ; westaway et al., b) . the vesicle packets associate closely with the convoluted membranes and paracrystalline arrays, which are thought to be the sites of proteolytic processing of ns and ns b (westaway et al., b) . these modified membranes are linked with the er, and ultrastructural studies have shown virions present in the er, cytoplasmic vesicles, golgi cisternae, and vacuoles. the results suggest that membranes containing the spherules responsible for replication may become associated with the er to facilitate delivery of genomes to viruses, budding into early compartments of the secretory pathway (mackenzie and westaway, ) . hepatitis c virus (hcv) is closely related to the flaviviruses, and its importance as a human pathogen has generated great interest in its mechanism of replication. until, recently infection models have not been available to study the replication complex of hcv, and the studies discussed here have focussed on the expression of the entire polyprotein from replicons gosert et al., ) . however, the recent production of a hcv that rep licates ef ficiently both in vivo and in cell culture (li ndenbac h et al. , ; wakita et al., ; zhong et al., ) will exp and the possi bilities for studying and understanding the viral replication cycle. hcv replication is thought to occur on membranes derived from the er as all studies of nsps have found them localized to this organelle (dubuisson et al., ; hugle et al., ; kim et al., ; wolk et al., ) . studies have also identified a ''membraneous web'' of membrane vesicles of $ -nm diameter associated with the er and a population of irregular doublemembraned vesicles. the web resembled the ''sponge-like inclusions'' seen in the liver of chimpanzees infected with hcv, suggesting it is physiologically relevant. interestingly, the great majority of the nsp synthesized by full-length genomes or subgenomic replicons may not be involved in rna replication (quinkert et al., ) . the bulk of the nsps associated with membranes isolated from cells expressing replicons is sensitive to protease, while in vitro replicase activity is resistant to protease and nuclease activity (el-hage and luo, ; quinkert et al., ) . the results suggest that replication of hcv takes place within membrane vesicles, rather than on the surface of the membraneous web. these vesicles may be associated with the membraneous web, but the similarity between hcv and the flaviviruses leaves open the possibility that the membrane invaginations responsible for replication may also form in the tgn but be closely associated with the er. studies have investigated which viral proteins are responsible for membrane rearrangements seen in cells infected with flaviviruses. the ns a of kunjin virus induces the characteristic convoluted membranes and paracrystalline arrays seen in flavivirus infections. the ns a-b protein also causes membrane rearrangement, but the highly condensed structures seen in infected cells are not produced until the ns b- protease cleaves ns a free from ns b (roosendaal et al., ) . the ns b then translocates to the nucleus (westaway et al., a) . interestingly, this contrasts with hcv where ns b (and ns a-b) konan et al., ) rather than ns a is able to induce the membranous structures. flaviviruses have been found to upregulate cell surface expression of mhc class i and ii in response to interferon (king and kesson, ; liu et al., ; lobigs et al., ) . this is not caused by effects of the ns a or ns b proteins on membrane traffic; instead flavivirus infection increases expression of the er peptide transporter, tap . this increases the supply of peptides that are necessary for the folding and export of newly synth esized mhc proteins from the er. inc reased tap expression is media ted by increas ed transcrip tional activ ity of p and can be induc ed in liver hepg cells by express ion of the hcv core/cap sid pro tein alon e ( herzer et al., ; mombu rg et al ., ) . whil e the cap sid/cor e prote in is able to in crease cell surface expression of mhc clas s i through increase expres sion of tap , exp ression of the hc v polyp rotein has been sho wn to slow the moveme nt of prote ins thr ough the secretory pathway of hos t cells ( konan et al ., ) . the rate of delive ry of mhc cl ass i to the plasm a me mbrane in cells infected with hc v was reduced three-to five fold relative to cu red contr ol cells. exp ression of the pre cursor ns a-b was fou nd to red uce er-to-g olgi traf fic two-to threefo ld (kon an et al., ) , while the ot her ns proteins of hc v inclu ding ns a and ns b, indiv idually or comb ined, were unabl e to interf ere with the traf ficking pathway . ns b a lone indu ces a memb raneo us web in ce lls , and both ns a-b and ns b indu ce, and locat e to, clust ered and aggregate d membr anes looking v ery similar to the me mbraneo us web seen in cells expre ssing rep licons. in addition to agg regated me mbrane s, ns a/b also ind uces, but does not coloca lize with , swol len vesicul ar structure s. thes es swo llen vesicl es have a similar morphology to the vesicles induced by the a protein of p o li ov ir us , wh ich swe lls er memb ranes and blocks sec retio n betwee n the er and the golgi appar atus (doe dens et al., ). konan et al . ( ) hypo thesize that the ns a/b could be func tioning in a sim ilar man ner to poliovi rus a. e. the nidovira les replicate in association with doub le-membraned vesicles . the nidovirus replicase is generated from two polyproteins the nidovi rales order comp rises the arterivi ridae, coron aviridae , and ron iviridae famil ies. the rep licase gene is co mposed of two ope n read ing fram es termed orf a and orf b. orf b is gen erated from a fram eshift in a, and both reading frame s encode co mplex poly proteins pro cessed by viral prote ases (go rbalenya et al., ; ziebu hr, ) . the arter ivirus orf b encode s nsps - , incl uding the rdrp (nsp ) and helicase (nsp ). the orf b, however , lacks hydroph obic dom ains able to target the rep licase to membr anes. intere stingl y, the hydroph obic domains necessar y for membr ane targetin g are enco ded by orf a in nsp , , and , sugge sting that orf a pr oteins produc e a scaffold to locate the viral rep lication -transcr iption compl ex to membr anes ( fig. d ) ( pedersen et al., ; van der meer et al., ) . a similar strategy is used by cov, for example mouse hepatitis virus (mhv) and severe acute respiratory syndrome-cov (sars-cov) (prentice et al., a,b) , where transmembrane domains are located in nsp , , and , and helicase and polymerase proteins are nsp and , respectively, and nsp encodes the methytransferase. the nidovirales have the largest coding capacity of the single-stranded rna viruses, and not all the nsps have been studied in detail. it is possible that other proteins encoded by orfs a and b, such as rna processing enzymes, are incorporated into the replication complex. several studies have investigated the intracellular sites of replication of equine arterivirus (eav), mhv, and sars-cov. such studies are difficult because during nidovirus infection, the processes of replication and envelopment occur on different membranes, and these may merge during encapsidation. furthermore, late during infection cells infected with mhv can form syncitia. newly synthesized mhv viral rna has been found in perinuclear sites colocalized with the rdrp (shi et al., ) , and depending on whether human or murine cells were infected, these sites colocalized with golgi or er membranes, respectively. similar studies in mouse l cells report that the polymerase and newly synthesized rna locate to late endosomes and endocytic carrier vesicles . this discrepancy is in part reconciled by later work showing that the subcellular distribution of the replicase proteins can change during the course of infection, since replicase proteins move to sites of envelopment in the ergic (bost et al., ) . this is supported by the finding that individual replicase proteins distribute differently following cell membrane fractionation (sims et al., ) . membrane fractionation has also been carried out by gosert et al. ( ) , who showed that several proteins encoded by orf a and b were associated with membranes, and when observed by immunogold electron microscopy, these were associated with rosettes of double-membraned vesicles - nm in diameter. the role of these vesicles in viral rna replication was confirmed by in situ hybridization of labeled riboprobes. double-membraned vesicles are also seen in cells infected with eav (pedersen et al., ) . eav replicase proteins accumulate in perinuclear regions containing ergic and er markers and colocalize with newly synthesized viral rna, again suggesting sites of genome replication. notably, similar structures can be produced by expression of arterivirus orf a-encoded proteins nsp - , which contain the membrane proteins thought to tether the replicase to membranes. double-membraned vesicles are usually rare in cells but are induced during autophagy. a role for autophagy during mhv infection is suggested because autophagy is induced in cells infected with mhv. furthermore, in cells lacking atg , a protein required for the formation of autophagosomes, there is a % reduction in virus yield and mhv fails to induce double-membraned vesicles (prentice et al., a) . electron micrographs show that the double-membraned vesicles induced by sars-cov extend from the er and can be labeled with antibodies specific for replicase proteins. this suggests that, in common with mhv, the vesicles are a site of replication . even though all sars-cov replicase proteins tested colocalize to punctate structures that accumulate near the nucleus, there are conflicting reports about their relationship with autophagosomes. in monkey vero cells, the replicase proteins colocalize with autophagosomes identified using antibodies against lc (prentice et al., a) . however, when autophagosomes are identified by expression of gfp-lc , the replicase proteins do not colocalize with the gfp signal . the vesicles induced by sars-cov are smaller at -to -nm diameter than autophagosomes ( - nm) and are labeled with er markers. this has lead snijder and colleagues to suggest that they are virus-induced extensions to the er, rather than bona fide autophagosomes (pedersen et al., ; snijder et al., ) . the precise origins of the membrane crescents that form at the start of autophagy are unclear, and a number of studies have suggested they may form from the er. this makes it possible that the double-membraned structures may be autophagosomes that have been modified by an accumulation of viral protein. determining if autophagy is beneficial to sars-cov replication will have to await studies in cells where key proteins in the autophagy pathway have been removed or suppressed by gene silencing. the asfiviruses, poxviruses, iridoviruses, and the phycodnaviruses are large dna viruses encoding hundreds of proteins from genomes ranging between and kbp. a comparison of protein sequences encoded by these viruses has suggested that they should be grouped together in a family of viruses called the nucleocytoplasmic large dna viruses (ncldv) (iyer et al., ) . sequence similarities are seen in the major capsid proteins, redox enzymes that maintain disulphide bonds in the cytosol, and proteins that regulate apoptosis; and the family has been extended to include the giant mimivirus isolated from the ameba acanthamoeba polyphaga (la scola et al., ) . even though these viruses infect a diverse range of hosts from different phyla, including vertebrates [poxviruses, african swine fever virus (asfv)], arthropods (entomopox, asfv, chloriridoviruses), amphibians and fish (ranavirus, megalocytivirus, and lymphocystivirus genera of the iridoviridae family), marine algae (phycodnaviruses), and protozoa (mimivirus), they all generate cytoplasmic factories as major sites of virus assembly and replication (illustrated in fig. ). the factories share many similarities with one another, again suggesting that this diverse group of viruses may be related and that the need to produce a virus factory in the cytoplasm was generated early in virus evolution. . asfv factories form next to the microtubule organizing center asfv is the sole member of the asfivirus genus, family asfarviridae but shares striking icosahedral similarity with the iridoviruses, phycodnaviruses, and mimivirus. asfv is a large double-stranded dna (dsdna) virus with a genome size ranging from to kbp. gene expression is a regulated cascade and immediate early, early, early/late, intermediate, and true late gene types have been characterized to date. the virion has multiple concentric layers with an electron-dense core at the center that contains the viral genome. a protein matrix surrounds the core, which in turn is enclosed by a lipid bilayer. finally, the bilayer is surrounded by a protein capsid layer. asfv can gain a third envelope when it buds from the plasma membrane at the tip of actin-rich projections that resemble filopodia (jouvenet et al., ) . asfv probably enters cells by receptor-mediated endocytosis, but the steps following entry are poorly understood. it is possible that a viral core is delivered into the cytoplasm intact; alternatively, cores may dissociate in endosomes requiring some mechanism of genome delivery across the endosome membrane. genome replication occurs both in the nucleus and cytoplasmic factories. transfer to the nucleus may involve microtubule transport since late gene expression is inhibited by agents that depolymerize microtubules and the dominant-negative dynein motor protein p -dynamitin (alonso et al., ; heath et al., ) . asfv does not produce nuclear inclusions analogous to those seen in herpesvirus and adenovirus infection, but there is evidence that small fragments of viral dna are synthesized in the nucleus. the major site of asfv dna replication is, however, the virus factory (rojo et al., ) . a. cytoplasmic factories formed during asfv infection are assembled at the microtubule organizing center asfv induces one principal factory in the cytoplasm during infection. electron microscopy shows that the virus factory excludes obvious cellular organelles and contains mostly viral dna, viral proteins, virus-induced membranes, and partially and fully assembled virions (table i; fig. a ; brookes et al., ; moura nunes et al., ; rouiller et al., ) . the mechanisms that target viral proteins, virus-induced membranes, and viral dna to the asfv factories are poorly understood. immunofluorescence staining for viral structural proteins generally reveals a strong signal at the factory and a weaker signal in the cytoplasm. the b lp protein (cap ), which is a viral chaperone involved in folding and membrane recruitment of the major capsid protein, p , is, for example, absent from the virus factories (cobbold et al., ; epifano et al., ) . this suggests that p is synthesized and folded in the cytoplasm and then recruited to factories. similarly, the viral dutpase, which is necessary for efficient replication, is excluded from the viral factory (oliveros et al., ) . since the bulk of viral dna synthesis occurs in the factory (garcía-beato et al., ) , it is not easy to explain how the viral dutpase edits uracil from progeny viral genomes, without being present at the site of viral dna synthesis and encapsidation. asfv factories disperse when cells are incubated with drugs that depolymerize microtubules (heath et al., ) suggesting their formation involves microtubule motors. this may involve dynein motor proteins since p -dynamitin, a dominant-negative version of the dynein motor, prevents both late asfv gene expression (heath et al., ) and vimentin recruitment to factories (see below and stefanovic et al., ) . yeast-twohybrid screens and in vitro pull-down experiments show that one asfv structural protein, p /j lp, interacts with dynein (alonso et al., ) . while direct binding of p /j lp to the motor protein has not been observed in infected cells, it is possible that the protein is involved in transporting some viral proteins into factories. the protein locates to virus factories and deletion of the e l gene encoding p /j lp generates factories that lack viral membranes, the major capsid protein p , and the polyprotein precursors (pp , and pp ) of the viral matrix (epifano et al., ; rodríguez et al., ) . p /j lp is a membrane protein with the bulk of the protein, including the dynein-binding motif, exposed to the cytosol. the p capsid protein and pp polyprotein associate with membranes before assembly into viruses (cobbold and wileman, ; cobbold et al., ; heath et al., ) . if these membranes contain p /j lp, it would provide a means of allowing recruitment to factories by retrograde transport along microtubules. the formation and morphology of asfv factories closely resemble the formation of aggresomes (heath et al., ) , a cellular response to accumulation of misfolded protein aggregates (johnston et al., ) . aggresomes are microtubule-dependent inclusions containing protein aggregates that human herpesvirus induces nuclear tegusomes (t). herpesviruses induce cytoplasmic assembly sites where envelopment and some tegument are acquired (env) in human herpesvirus , these sites include electron-dense bodies (db). iridoviruses induce multiple cytoplasmic virus factories (vf) and crystalline arrays (ca), both of which associate with mitochondria. reoviruses also induce multiple cytoplasmic virus factories (vf) and crystalline arrays (ca) that are enclosed within lysosomal membranes. alcamí et al., ; alonso et al., ; andrés et al., andrés et al., , borca et al., ; brookes et al., a,b; carrascosa et al., ; chacó n et al., ; cobbold et al., ; galindo et al., ; garcía-beato et al., ; heath et al., ; hingamp et al., ; jouvenet and wileman, ; jouvenet et al., ; martinez-pomares et al., ; moura nunes et al., ; rodríguez et al., ; rouiller et al., ; sanz et al., ; simón-mateo et al., ; sun et al., ; vigário et al., contents of cellular origin ubiquitin, hsp chaperone, g-tubulin, pericentrin, p , mdm surrounded by: er membranes, vimentin, p golgin, mitochondria, and tubulin. granja et al., ; heath et al., ; hingamp et al., ; jouvenet and wileman, ; netherton et al., netherton et al., , rojo et al., ; rouiller et al., ; stefanovic et al., poxviridae almazán et al., ; beaud and beaud, ; betakova et al., ; chiu et al., ; cudmore et al., ; da fonseca et al., ; davis and mathews, ; de silva and moss, ; domi and beaud, ; krijnse-locker et al., ; murcia-nicolas et al., ; nerenberg et al., ; ojeda et al., ; palacios et al., ; pedersen et al., ; reckmann et al., ; resch et al., ; risco et al., ; roper, ; salmons et al., ; senkevich et al., ; sodeik et al., ; szajner et al., a,b,c; tolonen et al., ; vanslyke and hruby, ; welsch et al., ; wolffe et al., ; yeh et al., ; yuwen et al., (continued) contents of cellular origin hmg a viral genome binding protein, hsp ; transient association, ubiquitin, ying-yang transcription factor, tbp transcription factor, sp transcription factor, rna polymerase ii, sumo- , ergic- c surrounded by: vimentin and mitochondria. broyles et al., ; dales and siminovitch, ; hsiao et al., ; hung et al., ; husain and moss, ; nerenberg et al., ; oh and broyles, ; palacios et al., ; risco et al., ; wilton and dales, iridoviridae, ranavirus appearance and contents f electron lucent, virus, viral dna, k early protein, k, k major capsid protein (orf r in fv ), k, k, k rana grylio virus dutpase (orf r in fv ). surrounded by vimentin, rough er, mitochondria and polysomes. chinchar et al., ; darlington et al., ; huang et al., ; goorha, , ; zhao et al., herpesviridae barnard et al ., ; de bruyn kops et al ., ; everett and maul, ; goodrich et al ., ; jahedi et al ., ; knipe et al., ; lamberti and weller, ; leopardi et al ., ; liptak et al., ; markovitz and roizman, ; olivo et al ., ; randall and dinwoodie, ; reynolds et al ., ; taus et al ., ; ward et al ., contents of cellular origin rna polymerase ii, eap ribosome component, proliferating cell antigen, retinoblastoma protein, p , dna ligase , dna polymerase a, promyelocytic leukemia (pml), dna-pkcs, ku nonhomologous end joining, bloom syndrome gene product, breast cancer-associated gene protein, msh , rad , wrn recq helicase family member, brg or brm-associated factor , brahma-related gene- protein, brahma protein, histone deacetylase , hsnf h, msin a, tata binding protein (tbp), tbp-associated factors. leopardi et al., ; quadt et al., ; taylor and knipe, ; wilcock and lane, nuclear sites of capsid assembly or assemblons contents of viral origin d ul (hhv- ), ul (hhv- ) tegument, ul capsid, ul icp major capsid protein, ul . icp dna packaging, ul dna packaging, ul vp p capsid, ul vp c capsid assembly, ul . , ul . de bruyn kops et al., ; goshima et al., ; nalwanga et al., ; nozawa et al., ; wada et al., ; ward et al., a,b; yamada et al., contents of cellular origin actin, myosin a actin motor feierbach et al., cytoplasmic assembly and envelopment site contents of viral origin d membranes, vacuoles, capsids and enveloped virus ul (hhv- ) vp major capsid protein ul (hhv- ) gb vp ul (hhv- ) icp - , tegument ul (hhv- ) tegument, ul (hhv- ) tegument kato et al., ; murata et al., ; nozawa et al., ; watanabe et al., contents of cellular origin mitochondria, g-tubulin, hsp chaperone, hsp chaperone, gm golgi marker murata et al., ; nozawa et al., (continued) becker et al., becker et al., , broering et al., ; cashdollar, ; dales et al., b; miller et al., ; sharpe et al., ; silverstein and schur, reoviridae, rotavirus appearance and contents electron-dense viroplasm, assembling and complete double-shelled particles vp , vp , vp , nsp , nsp , nsp altenburg et al., ; gonzález et al., ; petrie et al., petrie et al., , silvestri et al., silvestri et al., , a african swine fever virus gene nomenclature is based on that for the badajoz vero adapted strain with that of the malawi lil / strain in parentheses. b vaccinia virus gene nomenclature is based on that for the copenhagen strain with that of the western reserve strain in parentheses. c one report places in ergic- within the virosome (risco et al., ) , one report places it outside (husain and moss, ) . d open reading frames from human herpesvirus (herpes simplex virus ) unless specified otherwise. e open reading frames from human herpesvirus (human cytomegalovirus) unless specified. f proteins specified by frog virus unless indicated otherwise. form next to the microtubule-organizing center (mtoc). aggresomes recruit cellular components needed to deal with the problems associated with a buildup of aggregated misfolded protein. these include cellular chaperones and proteasomes to facilitate protein folding and/or degradation and mitochondria that may provide the atp required for folding and proteolysis. the most striking structural changes seen during aggresome formation are the collapse of the intermediate filament protein, vimentin, into a cage surrounding the protein aggregates and the gross fragmentation of the golgi apparatus. asfv factory formation shows many similarities with this response to protein aggregation. factory formation is preceded by clearance of cytoplasmic proteins from perinuclear areas around the mtoc. vimentin then concentrates at the mtoc where it forms an aster aligned along microtubules (stefanovic et al., ) . following the onset of virus dna replication and synthesis of late structural proteins, the vimentin aster is rearranged into a cage around the factory ( fig. b ; heath et al., ; monaghan et al., ; stefanovic et al., ) . during this period, mitochondria and cellular chaperones are recruited to the factory (heath et al., ; rojo et al., ) . formation of vimentin cages in asfv-infected cells is linked to phosphorylation of vimentin at serine by calcium calmodulindependent protein kinase ii (camkinase ii) (stefanovic et al., ) , and drugs that inhibit camkinase ii activity block late gene expression and vimentin rearrangement. as will be discussed for poxviruses and iridoviruses, the vimentin cage may form a physical scaffold within the factory, or act as a cage to prevent movement of viral components into the cytoplasm. chaperones recruited to the factory may facilitate folding of viral structural proteins during assembly, as has been shown for other viruses. the proximity of mitochondria to viral factories may provide the atp that is required for asfv assembly (cobbold et al., ) or be indicative of an antiviral response as mitochondria are effectors of apoptosis. taken together these results suggest that a cellular response originally designed to deal with the buildup of protein aggregates in cells is used by asfv to generate a site specialized for virus assembly. as will be described later, similarities between aggresomes and virus assembly sites are also seen for the iridoviruses and poxviruses. following the onset of asfv dna replication, the microtubule network becomes disorganized. microtubules are partially excluded from virus factories and form bundles and concentric rings in the cytoplasm (jouvenet and wileman, ) . asfv infection leads to disassembly of g-tubulin and pericentrin from the centrosome, and the centrosome becomes less able to nucleate microtubules. at the same time microtubules are stabilized by acetylation (jouvenet et al., ) . since pericentrin and g-tubulin play key roles in microtubule organization and nucleation at the mtoc, their loss from the centrosome, coupled with acetlylation of tubulin, may explain the rearrangement of microtubules induced by asfv. the reasons for these profound effects on microtubules are not known but they may facilitate disruption of the virus factory allowing release of assembled viruses into the cytoplasm. c. membrane rearrangements caused by asfv infection perturb the secretory pathway current models for asfv envelopment in virus factories predict that viral membranes are obtained from the er. the major structural proteins are recruited from the cytoplasm onto the cytoplasmic face of the er, and after which protein-protein interactions between these, and possibly viral proteins targeted to the er lumen, lead to constriction of er cisternae and clearance of host proteins from the er lumen prior to envelopment (andrés et al., ; netherton et al., netherton et al., , rouiller et al., ) . this is consistent with low levels of er proteins observed at asfv assembly sites by immunoelectronmicroscopy (rouiller et al., ) and standard fluorescence microscopy where er proteins appear to be actively excluded from areas of viral replication (andrés et al., ; netherton et al., ) . in addition to effects on the er, asfv also affects the structure and function of later golgi compartments of the secretory pathway (mccrossan et al., ; netherton et al., ) . golgi structure is linked to microtubule organization and the changes seen during infection may in part be related to effects of asfv infection on centrosome and microtubule function listed above. asfv infection causes dispersal of ergic marker protein ergic- , the peripheral golgi protein gm , and late golgi protein galnac-t transferase, suggesting disruption of ergic and golgi membrane compartments. most striking is the complete loss of the tgn. tgn loss is dependent on microtubules and involves dispersal of the tgn into separate vesicle populations containing either peripheral golgi proteins or the integral membrane protein, tgn . not surprisingly, this dispersal slows the transport of proteins through the secretory pathway. asfv slows the delivery of newly synthesized lysosomal enzymes to lysosomes (mccrossan et al., ) , and in macrophages reduces transport of newly synthesized mhc class i to the plasma membrane (netherton et al., ) . thus, in common with picornaviruses, disruption of the secretory pathway by asfv has the potential to slow the transport of important immunomodulatory proteins to the surface of infected cells and may mask them from immune surveillance. poxviruses are large dsdna viruses with genomes ranging from to kbp. poxvirus gene expression follows the regulated cascade of other large dsdna viruses with early, intermediate, and late transcripts described. poxvirus progeny genomes are replicated exclusively in the cytoplasm in virus factories. the virus encodes all the enzymes necessary for transcription and replication of its genome. genetic analysis has identified a minimum of five viral genes necessary for genome replication, these are a r, b r, d r, d r, and e l encoding the dna polymerase processivity factor, serine/threonine protein kinase, uracil dna glycosylase, dna-independent nucleoside triphosphatase, and the dna polymerase, respectively (de silva and moss, ; evans et al., ; millns et al., ; punjabi et al., ; rempel et al., ; sridhar and condit, ) . only the product of the d r gene, encoding the viral dna glycosylase, has been confirmed to localize to the site of genome synthesis (de silva and moss, ) , and it would be interesting to discover the subcellular location of the other members of the minimum replicase. when viewed by electron microscopy, infectious virions have a striking brick-shaped morphology, and different forms of virus are documented which vary in degree of complexity [for review, see condit et al. ( ) ]. the interior of all poxvirus particles contains the virus core which houses the viral genome. cores are enveloped in virus factories to produce the intracellular mature virus (imv), which is fully infectious. additional envelope layers gained at the tgn give rise to intracellular enveloped viruses (iev), which after budding through the plasma membrane form cell-associated and extracellular enveloped viruses (cev and eev). poxviruses induce two principal inclusions during infection, the a-type inclusion that is nonreplicative and the b-type inclusion where virus replication and assembly occur in the virus factory ( fig. ; kato et al., ). a. poxvirus a-type inclusions contain the mature intracellular virus but not enveloped viruses a-type inclusions are cytoplasmic bodies of dense homogeneous matter that contain mature virus particles and are studded with polyribosomes (fig. a) (ichihashi et al., ) . a-type inclusions are extremely rare in vaccinia, variola, and rabbit pox infections but are prominent in cowpox, ectromelia, fowlpox, and canarypox infections where they are also referred to as downie, marchal, bollinger, and burnet bodies, respectively (kato et al., ) . the major component of a-type inclusions is the product of the a l gene or its equivalents. in vaccinia, a is truncated and produces a protein of - kda whereas the fulllength gene in cowpox encodes a protein of kda (patel et al., ) , both versions are myristylated (martin et al., ) . immunfluorescence analysis of cells infected with vaccinia virus with antibodies raised against a does reveal multiple a-type inclusions in the cytoplasm, but they are much smaller than those seen in cells infected with cowpox, and do not contain virus particles (patel et al., ) . in cells infected with wild-type cowpox, only imv particles were observed within a-type inclusions, but treatment with rifampicin, a drug that blocks poxvirus maturation at an early stage in morphogenesis, caused aberrant immature virus particles to integrate into the inclusions (ichihashi et al., ) . the factor necessary for occlusion of viral particles in a-type inclusions has been identified as the c core protein (mckelvey et al., ; shida et al., ; ulaeto et al., ) . it has been hypothesized that c retains vaccinia virions within the cell as imvs in a-type inclusions preventing their transport to the tgn for envelopment and maturation to the iev types of virion (mckelvey et al., ) . a-type inclusions are predicted to protect imvs during transport between hosts akin to that of the polyhedra that occlude entomopox and baculoviruses (rohrmann, ) . therefore, eevs may be important for cell-to-cell spread, while imvs (whether occluded or not) may be more important for host-to-host spread (mckelvey et al., ) . b. poxvirus b-type inclusions are factories and are the main sites of replication and assembly b-type inclusions originally called guarnieri bodies (guarnieri, ) are the primary replication centers of the poxviruses, now generally referred to as virosomes or virus factories (fig. c) . electron microscopic analysis of b-type inclusions revealed a granular matrix that was denser than the surrounding cellular material and in a defined area of the cytoplasm called viroplasm (dales and siminovitch, ; higashi, ) . the factories also contain viral crescents consisting of membrane and viral proteins associated with viroplasm, spherical immature virus, and imvs (dales and siminovitch, ) . factories are surrounded by mitochondria, increase in number and size during the replication cycle and can occupy the majority of the cytoplasm at late times of infection (dales and siminovitch, ) . the assembly and envelopment of vaccinia virus within virus factories has been the subject of many studies and is discussed in papers and reviews (griffiths et al., ; heuser, ; hollinshead et al., ; sodeik and krijnse-locker, ) . here, we will review some of the early steps that lead up to the start of genome replication and factory production. these have also been described in a review (schramm and krijnse-locker, ) . it is generally believed that infection results in the delivery of viral cores into the cytoplasm. cores are seen associated with microtubules (carter et al., ; mallardo et al., ; ploubidou et al., ) and may use microtubules to reach perinuclear sites that will eventually house the virus factories. viral cores can transcribe as many as early mrnas before the onset of dna replication, and these early mrnas appear in discrete foci that associate with microtubules, contain polyribosomes and other translational machinery. it is unlikely that foci involved in transcribing early rnas mature into viral replication sites because they do not initiate dna synthesis (mallardo et al., ) . it is likely that each infecting virus can induce its own replication center (cairns, ) , but it is not clear where in the cell the cores initiate dna synthesis. it has been suggested that the onset of dna synthesis may occur at peripheral sites and therefore precedes delivery to the perinuclear region of the cell. when cells are incubated with hydroxyurea to prevent the onset of viral dna replication, it is possible to localize viral dna released into the cytoplasm. under these conditions, viral genomes are seen at several discrete sites that contain b protein kinase, e membrane protein, i ssdnabinding protein, and h late transcription factor (domi and beaud, ; welsch et al., ) . after removal of hydroxyurea, these foci begin to make new viral dna, showing that they are sites of dna replication. live cell imaging studies have shown that these initial sites of dna replication form in the cell periphery and then move toward the nucleus where they coalesce into large structures (schramm and krijnse-locker, ) . electron micrographs suggest that sites of dna release from cores are intimately associated with er membranes and become completely enclosed by them during the initial stages of dna replication (mallardo et al., ) . this process is likely facilitated by the e r gene product which is a membrane protein localized to the er and early golgi membranes, has dna-binding activity, and is able to capture viral genomes tolonen et al., ) . these er-enclosed genomes are short-lived structures because they are not seen once viral crescents, iv and imvs, appear in factories (tolonen et al., ) . the sites of dna replication are also separate from the foci involved in transcribing early rnas, and it is interesting to consider how the cores are separated from newly transcribed rna. viral cores and sites of rna transcription both align on microtubules and partially colocalize with the l core dna-binding protein (mallardo et al., ) . the l protein is able to bind microtubules (ploubidou et al., ) and may be involved in separating rna from cores along microtubule tracks (mallardo et al., ) . inducible recombinants or temperature-sensitive mutants grown under nonpermissive conditions can give further insight into the early stages of inclusion formation. electron micrographic analysis of the factories formed under these conditions yield striking images of distinct inclusions of homogeneous electron-dense viroplasm next to empty spherical immature virions ( fig. b and c) (szajner et al., (szajner et al., , (szajner et al., , a . a seven-protein complex comprising the gene products of the a l, a l, d l, d l, f l g l, and j r open reading frames has been identified as being necessary for association of viral membranes with the viroplasm (szajner et al., a) . consistent with this role, all of these proteins are known to localize to the virus factory except d and d (table i) ; however, these have been identified as core proteins (dyster and niles, ) so are likely to reside at viral assembly sites. localization of d l to the virus factory is sensitive to the antibiotic rifampicin (miner and hruby, ) , and treatment with this drug induces irregular shaped viral membranes instead of the well-defined hemispherical viral crescents seen in natural infection (moss et al., ; pennington et al., ) . therefore, it was suggested that d l may act as a scaffold on which the viral membrane is shaped, allowing correct association with the viroplasm (mohandas and dales, ) . deep etch electron microscopy has confirmed this role for d l, as it forms the honeycomb lattice identified as the outer coat of the viral membrane of immature virions (heuser, ; szajner et al., ) . interestingly, d l shares a structural similarity with structural proteins from many other virus families, including those of the other large dsdna viruses (benson et al., ) . it will be interesting to see if the structural similarities to d l translate to functional similarities in the assembly strategies of other viruses. to the viral factory. ying-yang (yy ), tbp, sp transcription factors, and rna polymerase ii are recruited from the nucleus to the factory (broyles et al., ; oh and broyles, ; wilton and dales, ) . yy is a nuclear transcription factor that can activate late viral promoters and although poxviruses encode most of the genes necessary for transcription, there is evidence that cellular factors may be required for intermediate and late gene expression (lackner and condit, ; rosales et al., ; wright et al., ) . the function of the other transcription factors in viral replication is unknown. they may be necessary for viral transcription like yy , or perhaps they are sequestered into the factory to divert them from their normal roles in the nucleus, or their presence may represent an antiviral response by the cell. the presence of rna polymerase ii in the viral factory is a surprise because the virus encodes its own rna polymerase activity which accounts for at least orfs and $ % of the genome capacity [western reserve (wr) strain]. another cellular protein recruited from the nucleus to the cytoplasm is the hmg a protein. this protein can bind the viral genome and has been implicated in host range restriction of vaccinia virus in chinese hamster ovary cells (hsiao et al., ) . during unproductive infection by vaccinia virus, hmg a is recruited from the nucleus to the factory where it binds viral dna. if the cowpox host range gene cp is artificially introduced into vaccinia virus then cp also enters the virus factory and binds to hmg a; the cellular protein then dissociates from the viral genome and replication proceeds (hsiao et al., ) . as seen for iridovirus and asfv replication sites, vaccinia factories are surrounded by a vimentin cage (risco et al., ; schepis et al., ) and recruit molecular chaperones (hung et al., ) , suggesting similarity with aggresomes. many proteins targeted to aggresomes are ubiqutinated, and most poxviruses encode a ring protein that is both a functional ubiquitin ligase and a virulence factor (nerenberg et al., ) . exceptions to this are the two most common laboratory strains of vaccinia, copenhagen and wr. the ring protein from the ihd-w strain of vaccinia is capable of directing transfected tagged ubiquitin to wr virus factories (nerenberg et al., ) ; however, it is unknown if native ubiquitin is localized to wr factories. the product of the a r gene of vaccinia is tagged with the ubiquitin-like protein sumo- , and this modification is necessary for a targeting to viral factories, where it associates with er membranes and may play a role in the formation of i sites (palacios et al., ) . it is not known if movement of sumolyated a and ubiquitinated protein is directed along microtubules in a manner analogous to hdac mediated targeting of misfolded proteins to aggresomes (kawaguchi et al., ) . as reported for asfv (see above) and cells infected with herpes simplex virus (avitabile et al., ) , infection of cells with vaccinia virus also leads to disruption of microtubule organization and centrosome function and dispersal of the golgi apparatus (ploubidou et al., ) . whether these are bystander effects of the production of virus factories close to the centrosome or induced deliberately to facilitate virus egress is not known. imv exit from the factory and transport to envelopment sites at the tgn is nonetheless dependent on microtubules (sanderson et al., ) and has been reported to be dependent on the a l and a l gene products (sanderson et al., ; ward, ) . following envelopment, the a l and f l gene products then regulate microtubule-dependent movement of intracellular enveloped viruses from the tgn to the plasma membrane (herrero-martínez et al., ; ward and moss, ). crystalline arrays a. iridoviruses iridoviruses are large dsdna viruses with genomes ranging from to kbp in length encoding between and proteins (williams et al., ) . much of the work on iridovirus replication has been carried out on the ranavirus frog virus (fv ). fv genome synthesis occurs in the nucleus and cytoplasm. no nuclear inclusions have been reported during fv infection, and as such it is unclear how the nuclear replication stage is mediated. however, viral dna is initially synthesized as units that are - genomes in length and then transported to the cytoplasm where multiple length concatemers are produced (goorha, ) . b. cytoplasmic factories formed during iridovirus infection resemble aggresomes infection induces two cytoplasmic inclusions. viral factories form in the cytoplasm and become the major site of viral dna replication. fv also induces large crystalline arrays of viral particles which give rise to the iridescent coloring of purified virus, and hosts, that are characteristic of iridovirus infections. virus factories are electron lucent relative to the cytoplasm and contain viral membranes, partially assembled viruses, and are surrounded by rough er membranes and polysomes. fv factories also resemble aggresomes since they recruit intermediate filaments (fig. a) and mitochondria, some of which show darlington et al. ( ) with permission from elsevier. signs of damage (darlington et al., ; granoff et al., ; huang et al., ; tripier et al., ) . crystalline arrays of virus are associated with virus factories and can induce nuclear deformations that lead to kidneyshaped nuclei similar to those seen in asfv infection (fig. b ) and after aggresome formation (darlington et al., ; heath et al., ; johnston et al., ) . as seen for asfv and poxviruses, the intermediate filament vimentin plays an important role in replication (murti and goorha, ) . vimentin is phosphorylated during fv infection, prior to factory formation (chen et al., ; willis et al., ) , and temperature-sensitive mutants that are unable to phosphorylate vimentin do not form vimentin cages and are unable to proceed to late gene expression. drug treatment with taxol or colchicine (murti et al., ) showed that recruitment of vimentin to assembly sites requires dynamic, but not polymerizing microtubules, and microinjection of anti-vimentin antibody prevented recruitment of vimentin to factories. this allowed intrusion of cell components into assembly sites and reduced virus growth by - % (murti et al., ) . vimentin may therefore provide a scaffold for iridovirus replication, maintaining a barrier between the cytoplasm and the contents of the virus factory. consistent with this hypothesis is the observation that during infection, polyribosomes and most newly synthesized viral proteins associate with intermediate filaments (murti and goorha, ) . fv factory formation may also be dependent on the early k protein, as it is recruited to factories in the absence of late protein synthesis (chinchar et al., ) . phycodnaviruses and the recently described giant virus mimivirus (la scola et al., ) induce replication complexes in the cytoplasm of infected ameba (meints et al., ; raoult et al., ) . the factories of the phycodnavirus paramecium bursaria chlorella virus (pbcv- ) are electron translucent areas of the cytoplasm and contain viral membranes, electron-dense viroplasm, and assembling viruses. unlike many viral factories, a distinct order appears to be present in pbcv- virosomes. the assembling viruses are arranged at the periphery of the virosome/ factory, giving the appearance of a rosette (meints et al., ) . phycodnavirus replication and factory formation are not affected by a wide range of pharmacological disruptors of the cytoskeleton, including microtubule depolymerization by nocodazole and taxol, and depolymerization of actin by cytochalasin d (nietfeldt et al., ) . in this way, they differ from factories formed by large dna viruses such as asfv, vaccinia, and fv . the successful cultivation of algae in the laboratory has allowed studies of the intracellular sites of replication of large icosahedral mclav- and hincv- viruses (wolf et al., (wolf et al., , . these viruses produce a latent infection that becomes apparent once the algae produce reproductive organs that become host to millions of virus particles. replication of these viruses begins in the nucleus, but the first evidence for virus assembly is provided by the appearance of electron-dense bodies next to the nucleus at sites of breakdown in the nuclear envelope. infection leads to stacking of er cisternae that may provide membranes for virus envelopment. the dense bodies remain next to the nucleus in large inclusions, and take on the angular shape characteristic of capsid assembly seen for iridoviruses and asfv. the nucleus eventually disintegrates, and the virus factory occupies most of the cytoplasm. herpesviruses are large dsdna viruses with genomes ranging in size from to kbp. herpesvirus genes are expressed in a regulated cascade starting with the immediate early a genes, then early b genes, and finally two subsets of late g genes, g and g . complete herpesvirus particles have four main layers, the core containing dna, an icosahedral capsid, a poorly defined layer of protein called tegument, and finally the viral envelope containing several glycoproteins. genome synthesis and packaging and capsid assembly occur in inclusions in the nucleus. nucleocapsids then obtain tegument in either the nucleus or the cytoplasm, or both, and the viral envelope is acquired exclusively in the cytoplasm [see mettenleiter ( ) and for more thorough analysis]. the transfer of virus from the nucleus to the cytoplasm and acquisition of tegument appears well defined for human herpesvirus (hhv- ) (roffman et al., ) but is controversial for the alphaherpesviruses (campadelli-fiume and roizman, ; mettenleiter and minson, ) . the subcellular organization of herpesvirus replication complexes formed in the nucleus during the early stages of productive infection has been described in considerable detail. the inclusions function as sites of virus replication and contain the virally encoded proteins and host proteins needed for virus replication. interestingly, nuclear inclusions formed during herpes virus replication also contain cellular proteins involved in the control of dna damage and repair. these may be recruited into inclusions in response to virus genome replication, and whether they are beneficial or detrimental to virus replication is a subject of considerable interest [reviewed by everett ( ) ]. herpesviruses enter the cell by fusing their envelopes with the plasma membrane, whereon the naked nucleocapsids migrate to nuclear pores, possibly along microtubules (granzow et al., ; sodeik et al., ) [reviewed by smith and enquist ( ) ]. nuclear inclusions housing herpesvirus dna replication are globular and can occupy the majority of the nucleus (de bruyn kops and knipe, ; randall and dinwoodie, ; taylor et al., ) . they are identified through the presence of the viral dna-binding protein encoded by the ul gene, which is also known as infected cell protein (icp ). a minimum set of seven genes, ul , ul , ul , ul , ul , ul , and ul , has been identified as necessary for viral dna replication (challberg, ) . a plasmid transfection system has shown in vitro these can form globular nuclear compartments that are sites of -bromo- -deoxyuridine (brdu) incorporation and visually are similar to those formed during infection zhong and hayward, ) . nuclear inclusions organizing viral dna replication have been followed in real time by a recombinant virus expressing a gfp-icp fusion protein. small inclusions merge with adjacent replication complexes and increase in size to form globular replication complexes, which eventually fill most of the nucleus (randall and dinwoodie, ; taylor et al., ) . replication compartments are formed from a number of different discrete foci that are induced early in infection and whose interrelatedness is not fully understood. the initial stages of productive herpesvirus infection are, however, intimately linked with nuclear structures called nd bodies (illustrated in fig. ) , maul et al. ( ) , review by borden ( ) ]. live cell studies have shown that the immediate early regulatory protein icp , which binds viral dna, forms discrete foci as early as -min postinfection (fig. a) . these initially appear close to the nuclear envelope, possibly at sites where the genome first enters the nucleus following capsid disassembly at nuclear pores (everett and murray, ) , and are then seen throughout the nucleus (everett et al., ) . icp foci are seen juxtaposed to the nd marker promyelocytic leukemia protein (pml) some -min later. the early and late regulatory protein icp is recruited to icp foci -h postinfection and facilitates efficient early gene expression (everett et al., ) . during the same period, the immediate early regulatory protein, icp , colocalizes with nd bodies, some of which are likely juxtaposed to icp bodies (everett et al., ) . icp mediates the ubiquitin and/or sumo- -targeted proteasomal degradation of nd components (chelbi-alix and de everett, ; everett and maul, ; everett et al., ) . finally, parental genomes localize to icp foci (everett and murray, ) , and the icp foci enlarge into structures that resemble early icp replication compartments (everett and murray, ; everett et al., ) . formation of icp replication compartments (taylor and knipe, ) is also known to involve redistribution of nd bodies (burkham et al., ) . the relationship between the early icp structures associated with parental genome and the later icp compartments associated with replication and production of progeny genome is not clear; however, icp and icp both localize to late replication compartments (knipe et al., ) . a description of the relative and temporal distribution of the two proteins at early times awaits live cell studies following both proteins simultaneously. a second prominent nuclear inclusion induced by herpesvirus infection is the assemblon (ward et al., b) . this is the site where capsid proteins accumulate and assemble into nucleocapsids (fig. b) . the assembly of herpesvirus nucleocapsids has been researched in great detail at the ultrastructural level facilitated by a cell-free system for reconstituting the particles (heymann et al., ; newcomb et al., newcomb et al., , . the mature herpesvirus capsid is icosahedral with a t ¼ symmetry and is composed of hexons and pentons of the major capsid protein ul . the place of the remaining penton is taken by a -mer of the portal protein ul , which by analogy with bacteriophage may be the site of genome entry. nucleocapsids mature from fragile procapsids, through b capsids that lack dna and contain the internal scaffold protein ul . , to c capsids that contain the viral genome. the relationship between assemblons and sites of viral dna replication has been a topic of some controversy as some reports show direct colocalization (taus et al., ) , whereas others have shown a proximity (nalwanga et al., ; ward et al., b) , similar to that seen between nd bodies and icp foci during the initial stages of infection. clearly, the dna has to reach the capsid in order to complete assembly, and it is likely that the different results are indicative of the dynamic interactions between different herpesvirus nuclear inclusions. the dna cleavage and packaging proteins encoded by the ul and ul genes are required for colocalization of viral dna and capsids (lamberti and weller, ; taus et al., ) . cells infected with a virus encoding a faulty ul gene exhibit nuclear localization of the capsid protein vp that is separate from replication sites (lamberti and weller, ) . similarly, in cells infected with mutants that lack functional ul , the icp protein fails to colocalize with icp and icp (taus et al., ) . actin also plays an important role in the correct nuclear subcompartmentalization of viral proteins. infection with hhv- or suid herpesvirus- causes actin filaments to assemble in the nucleus, prior to the accumulation of capsid proteins (feierbach et al., ) . depolymerization of actin with latrunculin a inhibited correct nuclear compartmentalization of a representative capsid protein (vp ). vp colocalizes with the actin motor myosin va (feierbach et al., ) , and capsid movement within the nucleus is inhibited by the myosin motor inhibitor , -butanedione monoxime (forest et al., ) . this suggests that the organization of nuclear inclusions involved in herpesvirus assembly is dependent on cellular actin filaments, and it will be interesting to see if the organization of inclusions housing viral dna replication sites is similarly dependent. other inclusion bodies have been reported in the nucleus of cells infected with herpesvirus. the tegument proteins vp and vp / localize to inclusion bodies that align closely but do not overlap icp /nd /icp pre-replication complexes or assemblon inclusions (hutchinson et al., ) . ul also localizes to structures that overlap but are distinct from assemblons and dna replication complexes (fig. b ) . ul localizes to type iv and type v intranuclear dense bodies as well as virions and cytoplasmic ribbon structures (baines et al., ) . the alkaline dnase encoded by the ul gene localizes to discrete electron-dense bodies within the nucleus that also contain b- nucleolar protein (lopez-iglesias et al., ; puvion-dutilleul and pichard, ) . it is unknown whether these different structures are related to each other, whether they are homogenous accumulations of the individual herpesvirus protein(s), or if they are simply dead-end accumulations of protein. a large number and variety of cellular proteins accumulate at nuclear sites of herpesvirus replication and assembly. a comprehensive proteomic analysis of icp interacting proteins revealed more than viral and cellular proteins that maybe recruited to dna replication sites (taylor and knipe, ) . a number of these interacting proteins were confirmed to localize to replication sites by microscopy experiments (taylor and knipe, ) , and these as well as proteins identified in other studies (leopardi et al., ; quadt et al., ; wilcock and lane, ) reveal that at least cellular proteins are known to localize to nuclear inclusions involved in dna replication during herpesvirus infection (table i) . the functions of these proteins span the expected functions of nuclear genes, including dna replication, transcription, chromatin remodeling, dna repair, recombination, and nonhomologous end joining. of particular importance is the recruitment of rna polymerase ii, which is required to transcribe the viral genome. rna polymerase ii is phosphorylated during viral infection by icp and icp , and the latter modification is required for targeting to replication complexes (dai-ju et al., ) . the role of all of these cellular genes in the viral replication cycle is poorly understood; however, cells deficient in wrn, a recq helicase family member, produced reduced virus yields while cells lacking ku , part of a nonhomologous end-joining protein complex, produced increased yields of virus (taylor and knipe, ) . the implication therefore is that some cellular proteins may be actively recruited to replication complexes to aid viral replication, and some may be recruited by the cell as part of an antiviral response or sequestered by the virus in inclusions to subvert their antiviral nature. pml is induced by interferon, suggesting an antiviral role. many of the genes shown to be required for recruitment of pml to viral pre-replication sites are part of the minimal set of genes required to synthesize viral dna. recruitment of pml to viral replication sites is, for example, dependent on the viral dna polymerase (ul ), the origin binding protein (ul gene) and the helicase-primase complex (ul , ul , and ul ) (burkham et al., ) . recent evidence has suggested that this may be the reason why icp causes dispersal of pml early in infection. pml knockdown by short interfering rnas (sirna) facilitates productive replication of icp null mutants of herpesvirus (everett et al., ; moreover, icp null mutants are hypersensitive to interferon in a manner dependent on pml (chee et al., ) . this is of particular importance because icp plays a role in determining whether herpesvirus induces a quiescent or a productive, lytic infection (mossman and smiley, ) . the tegument layer of alphaherpesviruses is composed of at least different proteins (mettenleiter, ) . us , ul , ul , ul , and ul are components of the tegument, and all are localized to the nucleus (if not exclusively) during the productive life cycle of the virus hutchinson et al., ; kopp et al., ; roller and roizman, ; taus et al., ) . ul may play a role in egress from the nucleus, though this has not been unequivocally established (mossman et al., ) . therefore, it is likely that some tegument proteins are acquired in or during viral egress from the nuclear inclusions. recently, cytoplasmic aggresome-like struct ure s have been desc ribed in ce lls infected with hhv- . these contain the major capsid protein, tegument proteins, envelope glycoproteins, and markers for the golgi complex (nozawa et al., ) . the latter finding is particularly interesting because herpesvirus envelopment involves membranes from the tgn turcotte et al., ) . hhv- is a betaherpesvirus and late during infection produces a juxtanuclear ''assembly compartment'' that again contains tegument proteins (pp , pp , and pp ), the major capsid protein, and viral envelope proteins (gb, gh, and gp ), suggesting a cytoplasmic site specialized for tegumentation and envelopment (fig. c) ; (adair et al., ; sanchez et al., ) . the precise role of the cytoplasmic assembly compartment is unclear. on the one hand, the concentration of glycoproteins and tegument proteins in one site may facilitate final stages of assembly prior to release from the cell. interestingly, in common with aggresomes induced by asfv and misfolded proteins, the cytoplasmic assembly compartment recruits chaperones and mitochondria and is dependent on microtubules and localizes to the microtubule organizing center. at present, the assembly compartments are not considered to be bona fide aggresomes because they are not surrounded by a collapsed cage of intermediate filaments (nozawa et al., ; sanchez et al., ) . it is nevertheless possible that these structures are related to aggresomes and are produced in response to a buildup of products resulting from nonproductive assembly pathways that occur late during infection. they may also contribute to the cytopathic effect seen in cells infected with hhv- . hhv- infection results in cytomegaly characterized by increased cell size and intracellular water content. cytomegaly and virus replication are both dependent on the presence of extracellular na þ , and infection results in sequestration of the plasma membrane na-k-cl-cotransporter protein in large perinuclear structures that resemble the assembly compartment/ viral aggresome (maglova et al., ) . electron-dense bodies can be seen by electron microscopy within the cytoplasmic assembly compartments induced during hhv- infection (craighead et al., ) . dense bodies are enveloped and obtain viral glycoproteins but do not contain dna and are noninfectious. as can be seen in fig. c , dense bodies bud into membranes and appear as oversized enveloped viral particles without a dna containing core. dense bodies exit the cell to become extracellular dense bodies (craighead et al., ) . interestingly, hhv- immediate early ie proteins also become associated with extracellular dense bodies despite no reported localization to their intracellular relations (tsutsui and yamazaki, ) . purified extracellular dense bodies are mostly composed of ul but have a full complement of viral glycoproteins (irmiere and gibson, ) . the function of dense bodies remain unclear, and they may represent the end point of a nonproductive assembly pathway resulting from attempts to envelope capsids lacking genomes or may be used to deliver viral components to neighboring cells. interestingly, for human herpesvirus (hhv- ), the tegument layer appears to be acquired within a dedicated structure that has been dubbed the tegusome (roffman et al., ) . this work is based on electron microscopy of cells infected with hhv- and shows tegusomes as intranuclear membrane compartments that abut the nuclear envelope (fig. d ). tegusomes may be cytoplasmic invaginations of the nuclear envelope into the nucleus because they appear to contain ribosomes and are sometimes in continuity with the cytoplasm. nucleocapsids appear to bud into the tegusome, capsids obtain a tegument layer, and then bud into cytoplasmic vacuoles where they acquire envelopes and exit the cell. adenovirus are medium-sized, nonenveloped dsdna viruses with genomes ranging from to kbp in length and virions of the order of - nm in diameter. like other dna viruses, they have an ordered cascade of transcripts, early, delayed early, and late types having been described. adenovirus transcripts are spliced to generate multiple transcripts from a given transcriptional unit. viral replication occurs in the nucleus, and adenovirus infection was utilized extensively as a model system for exploring different nuclear subcompartments. a productive infection of lytic adenovirus induces profound rearrangement of existing subcompartments and the induction of several new ones within the host nucleus. a study on the localization of the human adenovirus iva protein described distinct nuclear and nucleolar subcompartments induced or associated with virus replication (lutz et al., ) , and these are listed in table i . earlier studies carried out before markers for specific nuclear subcompartments were available have described the structures in terms of shape and location (see table i ). during the initial stage of infection, viral rna , single-stranded dna (ssdna), and dsdna (puvion-dutilleul and pichard, ) are all synthesized in small fibrillar regions termed early replication sites. by the intermediate stage of replication, the ssdna is deposited in the center of these structures, while transcription and dsdna synthesis occur on the outside and begin to form an inclusion. the inclusion has a characteristic doughnut shape, and has been called the fibrogranular network. at late stages of infection, dsdna, viruses, and trace amounts of ssdna appear in large viral inclusions (besse and puvion-dutilleul, ; puvion-dutilleul and pichard, ) . targeting of the initial replicon is dependent on a dcmp modification of the preterminal protein (ptp), which enables ptp to form a complex with the dna polymerase and the genome (temperley and hay, ) . ptp mediates targeting of the heterotrimeric complex to the nuclear matrix (fredman and engler, ) , possibly through an interaction with cad (carbamyl phosphate synthetase, aspartate transcarbamylase and dihydroorotase) (angeletti and engler, ) . transcription and splicing are mediated by host proteins and viral rna, and non-snp rna splicing factor, hnrnp c proteins, and rna polymerase ii all colocalize with viral rna in nuclear inclusions. splicing small nuclear ribonucleoproteins (snrnps) colocalize with viral rna but not replication foci (pombo et al., ) , and snrnps then move to interchromatin granules late in infection, which is blocked by mutations in e (bridge et al., ) . a. rearrangement of host nuclear compartments during adenovirus replication like herpesvirus described above, adenovirus infection redistributes the components of nd bodies. prior to infection, pml is associated with interchromatin granules but is redistributed to the fibrillogranular matrix within the nucleus along with sp , another nd component (carvalho et al., ) . later in infection, pml is redistributed once again from the fibrillogranular matrix to clear amorphous inclusions and protein crystals (puvion-dutilleul et al., ) . another study reported that sp and ndp , but not pml, were relocated from nd bodies to viral inclusions (doucas et al., ) . while this is confusing, it is clear that adenovirus employs multiple mechanisms to reorganize pml. the initial movement of pml, sp , and ndp to the fibrillogranular matrix occurs prior to viral dna synthesis and is dependent on the e -orf -kda protein (carvalho et al., ; doucas et al., ) . it may also be mediated by e a proteins that colocalize with pml (carvalho et al., ) . e b- -kda protein also colocalizes with pml early on in infection, then associates with the periphery of replication centers; these interactions are mediated by the orf protein of the e transcriptional unit (lethbridge et al., ) . interestingly, e b- k and e -orf target the mre -rad -nbs (mrn) complex to aggresomes for degradation (araujo et al., ; liu et al., ) . polyoma-and papillomaviruses are small double-stranded tumorigenic dna viruses with genomes of and kbp, respectively. replication and assembly of these two viruses follow similar strategies, and both involve nd bodies. the vp capsid protein of human polyomavirus jc is targeted to nd domains by vp , vp , and agnoprotein where they are assembled into virions (shishido-hara et al., ) . a similar process occurs during papillomavirus infection where the minor capsid protein, l , is responsible for targeting capsomeres of the major capsid protein, l , to nd domains (florin et al., a) . this process involves l -induced redistribution of nd bodies by targeting sp for proteasomal degradation. at this point the cellular daxx protein is recruited (florin et al., b) . daax has multiple functions in the nucleus including transcriptional activation and modulating fas-mediated apoptosis [reviewed by salomoni and khelifi ( ) ]. its role in virus replication is at present unclear. one characteristic of papillomavirus infections is the appearance of nuclear and cytoplasmic inclusions in cells contained within warts. the size and number of inclusions is dependent on the type of papillomavirus and the site of infection. human papillomavirus (hpv- ), for example, induces many small inclusions while hpv- induces one single inclusion that takes over most of the cytoplasm (croissant et al., ) . in vivo these structures label strongly with antiserum raised against e gene products which are the -kda e ∧ e and -kda e proteins (doorbar et al., ; rogel-gaillard et al., ) . inclusions can be induced in certain cell types in vitro by expressing e gene products. hpv- e staining reveals an initial association with the intermediate filament keratin and subsequent formation of inclusion bodies in the cytoplasm and nucleus (roberts et al., ; rogel-gaillard et al., ) . the hpv- cytoplasmic inclusions retain their association with keratin and appear to induce small cages surrounding e protein that are interconnected by keratin filaments (roberts et al., ) . the e gene gives rise to two proteins, the -kda e ∧ e which can induce cytoplasmic and nuclear inclusions whereas the -kda e can induce inclusions solely in the cytoplasm (rogel-gaillard et al., ) . interestingly, expression of e ∧ e gene product from hpv- induces the complete collapse of the keratin network, but not that of the microtubule or actin networks (doorbar et al., ) . it is unclear what the role of the inclusions is in viral replication or the pathology of infection. however, hpv- e expression induces the redistribution of nd to the periphery of nuclear inclusions in cells in culture, and similar signals are seen in vivo (roberts et al., ) . the temporal and functional connection between e and l redistribution of pml is unknown. members of the reoviridae family are dsrna viruses with segmented genomes and include the clinically important rotavirus and orbiviruses that cause diseases in human and animals. reoviruses are nonenveloped viruses with genome segments contained inside a virion $ nm in diameter. the genome is encapsidated by two protein shells, an outer capsid and an inner core shell. the core contains the rdrp, capping enzymes, and the dsrna genome segments [reviewed in yue and shatkin ( ) and furuichi and shatkin ( ) ]. viruses are taken up by receptor-mediated endocytosis, the outer capsid is lost and the core is delivered into the cytoplasm. the core does not disassemble on entering cells and imports ribonucleoside triphosphates and s-adenosyl-l-methionine from the cytosol to synthesize and then export viral mrnas. in this way the core particle functions as a self-contained transcriptional unit and as such represents the replication complex. viral mrna transcribed in the cytoplasm make viral proteins that eventually form large perinuclear inclusions, called virus factories that function as sites of further virus replication and assembly. the reoviridae family contains genera, and this chapter will concentrate on the two best characterized of these, the orthoreoviruses and rotaviruses. . formation of factories during orthoreoviruses replication and assembly a. the shape of orthoreovirus factories is determined by association with the cytoskeleton orthoreoviruses contain genome segments which are classed by size and then numbered, that is l is large segment . large segments encode l genes, medium (m) segments encode m genes, and small (s) segments encode s genes. virus replication occurs in the cytoplasm in virus factories, and the majority of the virus-encoded proteins have been shown to localize completely or partially with factories (table i ). early observations revealed that different strains of orthoreoviruses induced factories with different appearances; orthoreovirus type lang factories were filamentous while the factories of the dearing isolate of orthoreovirus type were globular ( fig. a and b) . this difference maps precisely to a serine-proline switch at residue of the m core protein . control of the localization of orthoreovirus factories reflects the degree of association m has with the microtubule network. filamentous virus m stabilizes microtubules to a greater relative degree than globular virus m , and depolymerizing microtubules with nocodazole convert filamentous factories to globular ones. many of the events of orthoreovirus factory formation have been successfully reconstituted in vitro. a screen of orthoreovirus proteins revealed that mns, sns, and s were the first viral proteins to localize with viral mrna prior to the synthesis of progeny dsrna (antczak and joklik, ) . subsequently, it was discovered that expression of the mns protein of isolate dearing in the absence of other viral proteins induced a phasedense structure that was indistinguishable in appearance from that observed during wild-type infection . the shape of the artificial mns inclusion could be altered from globular to filamentous by coexpressing a m protein from a filamentous virus . similar experiments showed that coexpression of l , l , and s core surface proteins with mns caused them to localize to the mns inclusion (broering et al., ) . furthermore, the shape of the mns structure that the core proteins colocalized to could be altered to filamentous by coexpressing m from a filamentous virus (broering et al., ) . mns can also recruit sns, but not s , to artificial inclusions (becker et al., ) , so other factors or conditions are necessary for complete assembly of an orthoreovirus factory. the precise domains involved in initiating factory formation are beginning to be elucidated. the minimal region of mns necessary for inclusion like body formation in vitro is the region composed of c-terminal amino acids of the residue proteins (broering et al., ) . residues - of sns are important for the interaction between sns and rna (gillian and nibert, ) , and treatment with rnase dissociates a proportion of mns from sns in coimmunoprecipiation experiments (miller et al., ) . interaction between mns and m is dependent on residues - or of mns and residues - are necessary for interaction between mns and sns (miller et al., ) . it is likely that factory formation occurs through an interaction between mns and a sns-rna complex; this can then recruit m that will determine the globular or filamentous localization of the factory and hence the localization of the other viral proteins. orthoreovirus factories are clearly intimately associated with the microtubule network (fig. c) and have also been suggested to interact with intermediate filaments. orthoreovirus type infection induces a redistribution of vimentin and viral inclusions reported to contain filamentous structures (sharpe et al., ) . it will be interesting to see if the in vitro factories induced by mns can also alter the distribution of the intermediate filament network. orthoreovirus factories are also ubiquitinated, and interestingly the nature of the factory determined the degree of ubiquitination; globular factories are prone to contain more ubiquitinated protein than filamentous ones . ubiquitination of orthoreovirus factories has been mapped to the m protein but is independent of the filamentous/globular factory determinate of m , that is converting a filamentous factory to a globular factory does not lead to an increase in ubiquitinated m . . formation of factories during rotavirus replication and assembly a. virus nonstructural proteins organize factory formation and virus assembly rotaviruses contain genome segments of dsrna and like the orthoreoviruses replicate in cytoplasmic factories. rotavirus virions are composed of three protein layers. these are the core which contains the genome and polymerase, an inner capsid layer, and an outer capsid layer. the core and inner capsid layer comprise the double-layered particle (dlp), while the addition of the third capsid layer forms the mature triple-layered particle (tlp). the acquisition of the third capsid layer occurs after the virus buds into the er, and in doing so obtains a transient envelope. rotavirus factories are composed of electron-dense viroplasm often in proximity to membranes derived from the er (fig. d) (altenburg et al., ) . viroplasm contains high levels of nsp (fig. e ) and nsp which are thought to coordinate assembly of the factory and recruitment of structural proteins such as the inner core protein vp and viral polymerase vp . the factory also contains double-layered rotaviruses, whereas the er membranes associated with the factory contain enveloped intermediates and tlp (arrowed in fig. d ). virus factories grow in size and decrease in number during the course of infection as neighboring factories merge (eichwald et al., ) . rotavirus factories appear to have an internal structure, as their centers occasionally appear more electron lucent than the periphery, giving a doughnut-like appearance (fig. e ). electron microscopy shows dlp at the periphery of the factory and this is (altenburg et al., ) consistent with fluorescent microscopy showing that the nonstructural protein nsp localizes to the center of the virus factory, whereas nsp and inner capsid protein vp localize to the periphery (eichwald et al., ; gonzález et al., ) . these different localizations could have functional relevance because vp binds the er-targeted nsp membrane protein and is implicated in the budding of dlps into er membranes associated with factories (silvestri et al., ) . therefore, a localization to the exterior of the factory may represent an organized progression of virus maturation from the interior of the viroplasm to the exterior. however, things are probably not that straightforward because vp is also part of the viral rna complex along with nsp (aponte et al., ) which, as noted above, is localized to the center of the viroplasm. virus factory-like structures can be introduced in vitro by coexpressing nsp and nsp (fabbretti et al., ) , and this is regulated by domains in the n-and c-termini (fabbretti et al., ) as well as the central portion of nsp (eichwald et al., ) . the process is also dependent on phosphorylation of nsp , possibly by cellular casein kinase ii (eichwald et al., ) . structures similar to factories can also be induced by expressing the inner capsid protein vp in vitro (nilsson et al., ) . these structures look similar to factories in the electron microscope but lack electron-lucent areas and dlps. interestingly, expression of vp of group a simian rotavirus sa- induced globular structures, whereas expression of vp from group c porcine rotavirus cowden/amc- induced filamentous structures (nilsson et al., ) analogous to the difference between type and type orthoretroviruses. it is not clear if the difference in factory shape is solely determined by vp and if this involves differences in association of the factory components with microtubules. b. virus factories organize viral rna replication and translation the factory does provide the virus with a mechanism to organize viral rnas. positive-stranded viral rna is utilized as the template for synthesizing progeny dsrna genomes and as mrna for translating viral proteins. interestingly, sirna-targeted degradation of nsp rna blocks translation of the protein but does not block genome synthesis (silvestri et al., ) . furthermore, rna synthesis occurs in factories, but viral rna transcribed in vitro and introduced to infected cells after infection does not localize to factories. the implication of these experiments are that the factory enables rotavirus to sort viral rna into separate pools, one within the factory to act as a template for the rna polymerase and genome replication, and the other outside the factory where it translated on ribosomes to make viral proteins. it likely that this organization allows the virus factory to protect dsrna genomes from antiviral responses. arenaviruses are negative-stranded rna viruses that have two singlestranded genome segments which are packaged into -to -nmdiameter enveloped virions. lassa, junín, and manchupo viruses are responsible for emerging hemorraghic fevers in humans. arenaviruses induce moderately electron-dense inclusions in the cytoplasm that are composed of -to -nm-diameter granules identical to those seen within virus particles in the electron microscope (murphy et al., ) . the granules represent host ribosomes and between and are packaged into virions (pedersen, ) . the inclusions increase in size and density during infection until cytopathic effects are observed in cells (buckley, ; buckley and casals, ) and stain positive for viral antigens (young et al., ) ; however, it is unclear if they represent true virus factories. arenavirus replication is believed to occur in the cytoplasm but also requires a nuclear step as limited growth is observed in enucleated cells (banerjee et al., ) . the viral z protein may play a role in this as it is sufficient in vitro to shuttle pml from the nucleus to cytoplasmic inclusion bodies as occurs in vivo (borden et al., ) . n protein also localizes to discrete nuclear foci, as well as in the cytoplasm (young et al., ) , but the relationship to nd bodies and z protein is unknown. rabies virus is a neurotropic lyssavirus of the rhabdovirus family. rhabdovirus virions are bullet-shaped  nm particles containing a single negative strand of rna. rabies induces two types of inclusion body in vitro, neither of which have been proven as replication sites. negri bodies are induced by street rabies viruses in infected neurons of the brain (negri, ) and are a good indicator for the presence of an infection site in tissue ( jackson et al., ) . different neuronal cell types appear to be more prone to negri bodies ( jackson et al., ) . negri bodies contain innerbodies (negri, ) and electron microscopic studies suggest the subcompartments may be cytoplasmic material engulfed by the coalescence of several smaller negri bodies (matsumoto, ) . the role of negri bodies in infection is poorly understood. initial em observations showed virions localized to some bodies in some cells (matsumoto et al., ) , and cytological staining show they contain genetic material, indicating they may be replication complexes. however, h-thymidine or h-uridine fail to label the structures, arguing against this conclusion (matsumoto, ) . fixed (brain-adapted laboratory strains) rabies can infect nonneuronal cell lines and in these cell types induce fuchsin-stained cytoplasmic structures (fcps) as well as negri-like bodies (ni et al., ) . fcps increase in size during infection that correlates with cytopathic effects and are composed of rabies glycoprotein and matrix protein, whereas negri bodies contain nucleocapsid (ni et al., ) . this chapter has described the changes to cell architecture that are induced during virus replication. we have focused on viruses that induce new cellular structures, such as inclusion bodies, virus factories, or replication complexes, to concentrate virus and host factors necessary for replication and assembly. much progress has been made in identifying which cellular components are used to generate these structures, and in some cases specific virus proteins have been identified that are able to induce them. virus inclusions often result in rearrangement of cellular membrane compartments and/or cytoskeleton. the functions of these organelles are carefully regulated in cells, and it is a challenge for the future to determine how viruses disrupt them for use as sites of replication and assembly. changes in cellular architecture may represent bystander responses to the stress associated with virus infection, and some viruses may replicate perfectly well without them. alternatively, viruses may have evolved to target key stages in the regulatory pathways that control organelle structure and function to generate sites that are essential for replication and assembly. given the coevolution of viruses with the cells that carry them, changes in cell structure induced during infection are likely to involve a combination of the two. it is also important to appreciate that many of the structures that have been studied to date have been generated by infecting tissue culture cells with attenuated viruses, often with disregard to the host range and tropism. it is possible that in the natural setting, changes in cell structure induced by viruses will be more subtle, particulary during persistent infections that occur without inflammation or cell lysis. the products of human cytomegalovirus genes ul , ul , ul and us are tegument components parallels among positive-strand rna viruses, reverse-transcribing viruses and double-stranded rna viruses mapping and sequence of the gene encoding the african swine fever virion protein of m r membrane permeabilization by poliovirus proteins b and bc the vaccinia virus superoxide dismutase-like protein (a r) is a virion component that is nonessential for virus replication african swine fever virus protein p interacts with the microtubular motor complex through direct binding to light-chain dynein ultrastructural study of rotavirus replication in cultured cells assembly of african swine fever virus: role of polyprotein pp african swine fever virus is enveloped by a two-membraned collapsed cisterna derived from the endoplasmic reticulum african swine fever virus protease, a new viral member of the sumo- -specific protease family adenovirus preterminal protein binds to the cad enzyme at active sites of viral dna replication on the nuclear matrix reovirus genome segment assortment into progeny genomes studied by the use of monoclonal antibodies directed against reovirus proteins recovery and characterization of a replicase complex in rotavirus-infected cells by using a monoclonal antibody against nsp adenovirus type e orf protein targets the mre complex to cytoplasmic aggresomes redistribution of microtubules and golgi-apparatus in herpes-simplex virusinfected cells and their role in viral exocytosis the herpes simplex virus ul proteins are associated with cytoplasmic and nuclear membranes and with nuclear bodies of infected cells requirement of cell nucleus for the replication of an arenavirus expression and characterization of a novel structural protein of human cytomegalovirus, pul preferential virosomal location of underphosphorylated h r protein synthesized in vaccinia virus-infected cells reovirus sns protein is required for nucleation of viral assembly complexes and formation of viral inclusions reovirus sns and mns proteins form cytoplasmic inclusion structures in the absence of viral infection poliovirus proteins induce membrane association of gtpase adp-ribosylation factor hijacking components of the secretory pathway for replication of poliovirus rna does common architecture reveal a viral lineage spanning all three domains of life? deletion mutants of the herpes simplex virus type ul protein: effect on dna synthesis and ability to interact with and influence the intracellular localization of the ul and ul proteins poliovirus mutant that contains a cold-sensitive defect in viral rna synthesis high resolution localization of replicating viral genome in adenovirus-infected hela cells the vaccinia virus a . l gene encodes a hydrophobic -amino-acid virion membrane protein that enhances virulence in mice and is conserved among vertebrate poxviruses intracellular distribution of poliovirus proteins and the induction of virus-specific cytoplasmic structures association of polioviral proteins of the p genomic region with the viral replication complex and virus-induced membrane synthesis as visualized by electron microscopic immunocytochemistry and autoradiography the mechanisms of vesicle budding and fusion a structural dna binding protein of african swine fever virus with similarity to bacterial histone-like proteins pondering the promyelocytic leukemia protein (pml) puzzle: possible functions for pml nuclear bodies an arenavirus ring (zincbinding) protein binds the oncoprotein promyelocyte leukemia protein (pml) and relocates pml nuclear bodies to the cytoplasm endoplasmic reticulum architecture: structures in flux nuclear factor i is specifically targeted to discrete subnuclear sites in adenovirus type -infected cells mouse hepatitis virus replicase protein complexes are translocated to sites of m protein accumulation in the ergic at late times of infection an amino-terminal amphipathic alpha-helix mediates membrane association of the hepatitis c virus nonstructural protein a adenovirus early region promotes the localization of splicing factors and viral rna in late-phase interchromatin granule clusters mammalian reovirus nonstructural protein mns forms large inclusions and colocalizes with reovirus microtubule-associated protein m in transfected cells reovirus nonstructural protein mns recruits viral core surface proteins and entering core particles to factory-like inclusions carboxyl-proximal regions of reovirus nonstructural protein mns necessary and sufficient for forming factory-like inclusions assembly of african swine fever virus: quantitative ultrastructural analysis in vitro and in vivo intracellular virus dna distribution and the acquisition of the nucleoprotein core during african swine fever virus particle assembly: ultrastructural in situ hybridisation and dnase-gold labelling characterization of african swine fever virion proteins j r and j l: immuno-localization in virus particles and assembly transcription factor yy is a vaccinia virus late promoter activator junín and tacaribe work in hela cells lassa fever, a new virus disease of man from west africa. . isolation and characterization of the virus nd protein pml is recruited to herpes simplex virus type prereplicative sites and replication compartments in the presence of viral dna polymerase interactions of herpes simplex virus type with nd and recruitment of pml to replication compartments the initiation of vaccinia infection the egress of herpesviruses from cells: the unanswered questions localization of structural proteins in african swine fever virus particles by immunoelectron microscopy vaccinia virus cores are transported on microtubules targeting of adenovirus e a and e -orf proteins to nuclear matrix-associated pml bodies characterization and structural localization of the reovirus l protein the african swine fever virus iap homolg is a late structural polypeptide herpes simplex virus dna replication promyelocytic leukemia protein mediates interferon-based anti-herpes simplex virus effects herpes virus induced proteasome-dependent degradation of the nuclear bodies-associated pml and sp proteins interaction of frog virus with the cytomatrix. iv. phosphorylation of vimentin precedes the reorganization of intermediate filaments around the virus assembly sites copi activity coupled with fatty acid biosynthesis is required for viral replication early proteins are required for the formation of frog virus assembly sites effects of a temperature sensitivity mutation in the j r protein component of a complex required for vaccinia virus assembly membrane rearrangement and vesicle induction by recombinant poliovirus c and bc in human cells inhibition of cellular protein secretion by picornaviral a proteins the major structural protein of african swine fever virus, p , is packaged into large structures, indicative of viral capsid or matrix precursors, on the endoplasmic reticulum involvement of the endoplasmic reticulum in the assembly and envelopment of african swine fever virus biochemical requirements of virus wrapping by the endoplasmic reticulum calcium store during envelopment of african swine fever virus a virally encoded chaperone specialized for folding of the major capsid protein of african swine fever virus in a nutshell: structure and assembly of the vaccinia virion inhibition of protein trafficking by coxsackievirus b : multiple viral proteins target a single organelle nonviral microbodies with viral antigenicity produced in cytomegalovirus-infected cells specificity of cytopathic effect of cutaneous human papillomaviruses the poliovirus replication machinery can escape inhibition by an antiviral drug that targets a host cell protein brefeldin a inhibits cell-free, de novo synthesis of poliovirus a vaccinia virus core protein, p , is membrane associated characterization of the vaccinia virus h l envelope protein: topology and posttranslational membrane insertion via the c-terminal hydrophobic tail icp interacts with the c-terminal domain of rna polymerase ii and facilitates its recruitment to herpes simplex virus transcription sites, where it undergoes proteasomal degradation during infection analysis of intracellular and intraviral localization of the human cytomegalovirus ul protein the development of vaccinia virus in earle's l strain cells as examined by electron microscopy electron microscopic study of the formation of poliovirus the uptake and development of reovirus in strain l cells followed with labeled viral ribonucleic acid and ferritin-antibody conjugates viruses and renal carcinoma of rana pipiens: ii. ultrastructural studies and sequential development of virus isolated from normal and tumor tissue acidic c terminus of vaccinia virus dnabinding protein interacts with ribonucleotide reductase formation of dna replication structures in herpes virus-infected cells requires a viral dna binding protein comparison of the intranuclear distributions of herpes simplex virus proteins involved in various viral functions origin-independent plasmid replication occurs in vaccinia virus cytoplasmic factories and requires all five known poxvirus replication factors mhc i-dependent antigen presentation is inhibited by poliovirus protein a autophagy in innate and adaptive immunity poliovirus a protein limits interleukin- (il- ), il- , and beta interferon secretion during viral infection inhibition of cellular protein secretion by poliovirus proteins b and a inhibition of endoplasmic reticulum-to-golgi traffic by poliovirus protein a: genetic and ultrastructural analysis the vaccinia virus e r gene product: a viral membrane protein that is made early in infection and packaged into the virions' core the punctate sites of accumulation of vaccinia virus early proteins are precursors of sites of viral dna synthesis identification of the human papilloma virus- a e gene products specific interaction between hpv- e -e and cytokeratins results in collapse of the epithelial cell intermediate filament network adenovirus replication is coupled with the dynamic properties of the pml nuclear structure interaction of hepatitis c virus proteins with host cell membranes and lipids genetic and biochemical characterization of vaccinia virus genes d l and d r which encode virion structural proteins intracellular location and translocation of silent and active poliovirus replication complexes reversible dissociation of the poliovirus replication complex: functions and interactions of its components in viral rna synthesis formation of the poliovirus replication complex requires coupled viral translation, vesicle production, and viral rna synthesis expression of hepatitis c virus proteins induces distinct membrane alterations including a candidate viral replication complex rotavirus nsp : mapping phosphorylation sites and kinase activation and viroplasm localization domains characterization of rotavirus nsp / nsp interactions and the dynamics of viroplasm formation replication of hepatitis c virus rna occurs in a membranebound replication complex containing nonstructural viral proteins and rna amphipathic helix-dependent localization of ns a mediates hepatitis c virus rna replication the african swine fever virus non-structural protein pb l is required for the formation of the icosahedral capsid of the virus particle the vaccinia virus d protein, which is required for dna replication, is a nucleic acid-independent nucleoside triphosphatase icp induces the accumulation of colocalizing conjugated ubiquitin interactions between dna viruses, nd and the dna damage response hsv- ie protein vmw causes redistribution of pml nd components relocate to sites associated with herpes simplex virus type nucleoprotein complexes during virus infection recruitment of herpes simplex virus type transcriptional regulatory protein icp into foci juxtaposed to nd in live, infected cells formation of nuclear foci of the herpes simplex virus type regulatory protein icp at early times of infection: localization, dynamics, recruitment of icp , and evidence for the de novo induction of nd -like complexes pml contributes to a cellular mechanism of repression of herpes simplex virus type infection that is inactivated by icp two non-structural rotavirus proteins, nsp and nsp , form viroplasm-like structures in vivo alpha-herpesvirus infection induces the formation of nuclear actin filaments assembly and translocation of papillomavirus capsid proteins reorganization of nuclear domain induced by papillomavirus capsid protein l active intranuclear movement of herpesvirus capsids adenovirus precursor to terminal protein interacts with the nuclear matrix in vivo and in vitro alphavirus rna replicase is located on the cytoplasmic surface of endosomes and lysosomes the ul tegument protein of pseudorabies virus is critical for intracytoplasmic assembly of infectious virions viral and cellular mrna capping: past and prospects characterization of the african swine fever virus protein p : a new late structural polypeptide role of the host cell nucleus in the replication of african swine fever virus dna differential requirements for copi coats in formation of replication complexes among three genera of picornaviridae amino terminus of reovirus nonstructural protein sns is important for ssrna binding and nucleoprotein complex formation relative localization of viroplasmic and endoplasmic reticulum-resident rotavirus proteins in infected cells localization of the herpes simplex virus type -kilodalton dna-binding protein and dna polymerase in the presence and absence of viral dna synthesis frog virus dna replication occurs in two stages a new superfamily of putative ntpbinding domains encoded by genomes of small dna and rna viruses nidovirales: evolving the largest rna virus genome rna replication of mouse hepatitis virus takes place at double-membrane vesicles identification of the hepatitis c virus rna replication complex in huh- cells harboring subgenomic replicons subcellular localization of the us protein kinase of herpes simplex virus type modulation of p cellular function and cell death by african swine fever virus viruses and renal carcinoma of rana pipiens. i. the isolation and properties of virus from normal and tumor tissue ultrastructural analysis of the replication cycle of pseudorabies virus in cell culture: a reassessment structure and assembly of intracellular mature vaccinia virus: thin-section analyses recherches sur la pathologie et étiologie de l'infection vaccinique et varioleuse subcellular localization of host and viral proteins associated with tobamovirus rna replication aggresomes resemble sites specialized for virus assembly membrane association facilitates the correct processing of pp during production of the major matrix proteins of african swine fever virus vaccinia virus intracellular enveloped virions move to the cell periphery on microtubules in the absence of the a r protein upregulation of major histocompatibility complex class i on liver cells by hepatitis c virus core protein via p and tap impairs natural killer cell cytotoxicity deep-etch em reveals that the early poxvirus envelope is a single membrane bilayer stabilized by a geodetic ''honeycomb'' surface coat dynamics of herpes simplex virus capsid maturation visualized by time-lapse cryo-electron microscopy electron microscopy of viruses in thin sections of cells grown in culture a ubiquitin conjugating enzyme encoded by african swine fever virus vaccinia virus intracellular mature virions contain only one lipid membrane a poxvirus host range protein, cp , binds to a cellular protein, hmg a, and regulates its dissociation from the vaccinia virus genome in cho-k cells electron microscopic examination of the viromatrix of rana grylio virus in a fish cell line the hepatitis c virus nonstructural protein b is an integral endoplasmic reticulum membrane protein molecular chaperone hsp is important for vaccinia virus growth in cells evidence against an essential role of copii-mediated cargo transport to the endoplasmic reticulum-golgi intermediate compartment in the formation of the primary membrane of vaccinia virus sequential localization of two herpes simplex virus tegument proteins to punctate nuclear dots adjacent to icp domains biogenesis of poxviruses: role of a-type inclusions and host cell membranes in virus dissemination isolation and characterization of a noninfectious virionlike particle released from cells infected with human strains of cytomegalovirus involvement of membrane traffic in the replication of poliovirus genomes: effects of brefeldin a the periphery of nuclear domain (nd ) as site of dna virus deposition common origin of four diverse families of large eukaryotic dna viruses quantitative study of the infection in brain neurons in human rabies subversion of cellular autophagosomal machinery by rna viruses colocalization of the herpes simplex virus ul protein with infected cell protein in small, dense nuclear structures formed prior to onset of dna synthesis aggresomes: a cellular response to misfolded proteins african swine fever virus infection disrupts centrosome assembly and function transport of african swine fever virus from assembly sites to the plasma membrane is dependent on microtubules and conventional kinesin african swine fever virus induces filopodia-like projections at the plasma membrane a study on the morphological and cyto-immunological relationship between the inclusions of variola, cowpox, rabbitpox, vaccinia (variola origin) and vaccinia ihd and a consideration of the term ''guarnieri body synthesis, subcellular localization and vp interaction of the herpes simplex virus type ul gene product the deacetylase hdac regulates aggresome formation and cell viability in response to misfolded protein stress subcellular localization of hepatitis c viral proteins in mammalian cells interferon-independent increases in class i major histocompatibility complex antigen expression follow flavivirus infection cellular autophagy: surrender, avoidance and subversion by microorganisms stages in the nuclear association of the herpes simplex virus transcriptional activator protein icp foot-and-mouth disease virus replication sites form next to the nucleus and close to the golgi apparatus, but exclude marker proteins associated with host membrane compartments nonstructural protein precursor ns a/b from hepatitis c virus alters function and ultrastructure of host secretory apparatus poliovirus protein a binds and inactivates lis , causing block of membrane protein trafficking and deregulation of cell division identification and characterization of the pseudorabies virus tegument proteins ul and ul : role for ul in virion morphogenesis in the cytoplasm the role of a -kda viral membrane protein in the assembly of vaccinia virus from the intermediate compartment replication complex of human parechovirus a giant virus in amoebae vaccinia virus gene a r dna helicase is a transcript release factor the herpes simplex virus type cleavage/packaging protein, ul , is involved in efficient localization of capsids to replication compartments human cytomegalovirus structural components: intracellular and intraviral localization of p characterization of rubella virus replication complexes using antibodies to double-stranded rna association of herpes simplex virus regulatory protein icp with transcriptional complexes containing eap, icp , rna polymerase ii, and viral dna requires posttranslational modification by the u(l) proteinkinase nuclear matrix localization and sumo- modification of adenovirus type e b k protein are controlled by e orf protein development by self-digestion: molecular mechanisms and biological functions of autophagy cell culture-grown hepatitis c virus is infectious in vivo and can be recultured in vitro secretory protein trafficking and organelle dynamics in living cells functional order of assembly of herpes simplex virus dna replication proteins into prereplicative site structures flavivirus infection up-regulates the expression of class i and class ii major histocompatibility antigens on and enhances t cell recognition of astrocytes in vitro adenovirus exploits the cellular aggresome response to accelerate inactivation of the mrn complex evidence that a mechanism for efficient flavivirus budding upregulates mhc class i herpes simplex virus type -induced modifications in the distribution of nucleolar b- protein formation of herpes simplex virus type replication compartments by transfection: requirements and localization to nuclear domain herpes simplex virus type prereplicative sites are a heterogeneous population: only a subset are likely to be precursors to replication compartments nucleoplasmic and nucleolar distribution of the adenovirus iva gene product visualization and functional analysis of rna-dependent rna polymerase lattices wrapping things up about virus rna replication assembly and maturation of the flavivirus kunjin virus appear to occur in the rough endoplasmic reticulum and along the secretory pathway, respectively subcellular localization and some biochemical properties of the flavivirus kunjin nonstructural proteins ns a and ns a markers for trans-golgi membranes and the intermediate compartment localize to induced membranes with distinct replication functions in flavivirus-infected cells rubella virus replication complexes are virus-modified lysosomes perinuclear localization of na-k-clcotransporter protein after human cytomegalovirus infection microtubule-dependent organization of vaccinia virus core-derived early mrnas into distinct cytoplasmic structures relationship between vaccinia virus intracellular cores, early mrnas, and dna replication sites small dense nuclear bodies are the site of localization of herpes simplex virus u(l) and u(l) proteins and of icp only when the latter protein is present novel acylation of poxvirus a-type inclusion proteins characterization of the african swine fever virus structural protein p . a dna binding protein rabies virus further studies on the replication of rabies and rabies-like viruses in organized cultures of mammalian neural tissues nuclear domain as preexisting potential replication start sites of herpes simplex virus type- inhibition of poliovirus rna synthesis by brefeldin a the trans golgi network is lost from cells infected with african swine fever virus identification of the orthopoxvirus p c gene, which encodes a structural protein that directs intracellular mature virus particles into a-type inclusions assembly site of the virus pbcv- in a chlorella-like green alga: ultrastructural studies herpesvirus assembly and egress egress of alphaherpes viruses herpesvirus assembly: a tale of two membranes flock house virus rna polymerase is a transmembrane protein with amino-terminal sequences sufficient for mitochondrial localization and membrane insertion reovirus sns protein localizes to inclusions through an association requiring the mns amino terminus increased ubiquitination and other covariant phenotypes attributed to a strain-and temperature-dependent defect of reovirus core protein m the vaccinia virus-encoded uracil dna glycosylase has an essential role in viral dna replication rifampicin prevents virosome localization of l , an essential vaccinia virus polypeptide effects of foot-and-mouth disease virus nonstructural proteins on the structure and function of the early secretory pathway: bc but not a blocks endoplasmic reticulum-to-golgi transport inhibition of the secretory pathway by the foot-and-mouth disease virus bc protein is reproduced by co-expression of b with c and the site of inhibition is determined by the subcellular location of c involvement of spicules in the formation of vaccinia virus envelopes elucidated by a conditional lethal mutant modulation of transporter associated with antigen processing (tap)-mediated peptide import into the endoplasmic reticulum by flavivirus infection high-pressure freezing in the study of animal pathogens the ultrastructure of the developing replication site in foot-and-mouth disease virus-infected bhk- cells membrane association of the rna-dependent rna polymerase is essential for hepatitis c virus rna replication structure and development of viruses observed in the electron microscope. ii. vaccinia and fowl pox viruses rifampicin: a specific inhibitor of vaccinia virus assembly herpes simplex virus icp and icp . counteract distinct interferon-induced barriers to virus replication evidence that herpes simplex virus vp is required for viral egress downstream of the initial envelopment event ultrastructural study of african swine fever virus replication in cultures of swine bone marrow cells mitochondrial distribution and function in herpes simplex virusinfected cells identification by mass spectroscopy of three major early proteins associated with virosomes in vaccinia virusinfected cells arenoviruses in vero cells: ultrastructural studies interaction of frog virus- with the cytoskeleton. i. altered organization of microtubules, intermediate filaments, and microfilaments synthesis of frog virus proteins occurs on intermediate filament-bound polyribosomes a functional role for intermediate filaments in the formation of frog virus assembly sites localization of adenovirus-encoded dna replication proteins in the nucleus by immunogold electron microscopy the ul gene product of herpes simplex virus is a virion protein that colocalizes with intranuclear capsid proteins beitrag zum studium de aetiologie der tollwuth Ü ber die morphologie und den entwicklungszyklus des parasiten der tollwut the poxviral ring protein p is a ubiquitin ligase that targets ubiquitin to viral replication factories the subcellular distribution of multigene family proteins of african swine fever virus is determined by differences in c-terminal kdel endoplasmic reticulum retention motifs african swine fever virus causes microtubule dependent dispersal of the trans-golgi network and slows delivery of membrane protein to the plasma membrane cell-free assembly of the herpes simplex virus capsid assembly of the herpes simplex virus capsid: characterization of intermediates observed during cell-free capsid formation poliovirus protein a inhibits tumor necrosis factor (tnf)-induced apoptosis by eliminating the tnf receptor from the cell surface ultrastructural studies of kunjin virus-infected aedes albopictus cells studies on unusual cytoplasmic structures which contain rabies virus envelope proteins chlorella virus pbcv- replication is not affected by cytoskeletal disruptors assembly of viroplasm and virus-like particles of rotavirus by a semliki forest virus replicon virus factories: associations of cell organelles for viral replication and morphogenesis identification and characterization of the ul gene product of herpes simplex virus type formation of aggresome-like structures in herpes simplex virus type -infected cells and a potential role in virus assembly subcellular distribution of the foot-and-mouth disease virus a protein in cells infected with viruses encoding wild-type and bovine-attenuated forms of a host cell nuclear proteins are recruited to cytoplasmic vaccinia virus replication complexes entry of vaccinia virus and cell-cell fusion require a highly conserved cysteine-rich membrane protein encoded by the a l gene african swine fever virus dutpase is a highly specific enzyme required for efficient replication in swine macrophages herpes simplex virus gene products required for dna replication: identification and overexpression bfa bodies'': a subcompartment of the endoplasmic reticulum quantitative sumo- modification of a vaccinia virus protein is required for its specific localization and prevents its self-association reovirus core protein m determines the filamentous morphology of viral inclusion bodies by interacting with and stabilizing microtubules isolation of cowpox virus a-type inclusions and characterization of their major protein component structural components and replication of arenaviruses open reading frame a-encoded subunits of the arterivirus replicase induce endoplasmic reticulum-derived double-membrane vesicles which carry the viral replication complex characterization of vaccinia virus intracellular cores: implications for viral uncoating and core structure events in vaccinia virus-infected cells following the reversal of the antiviral action of rifampicin localization of rotavirus antigens in infected cells by ultrastructural immunocytochemistry ultrastructural localization of rotavirus antigens using colloidal gold immunoelectron microscopy analysis of hcmv gpul (gn) localization vaccinia virus infection disrupts microtubule organization and centrosome function adenovirus replication and transcription sites are spatially separated in the nucleus of infected cells coronavirus replication complex formation utilizes components of cellular autophagy identification and characterization of severe acute respiratory syndrome coronavirus replicase proteins detection and subcellular localization of the turnip yellow mosaic virus k replication protein in infected cells clustered charge-to-alanine mutagenesis of the vaccinia virus a gene: temperaturesensitive mutants have a dna-minus phenotype and are defective in the production of processive dna polymerase activity simultaneous detection of highly phosphorylated proteins and viral major dna binding protein distribution in nuclei of adenovirus type -infected hela cells viral alkaline nuclease in intranuclear dense bodies induced by herpes simplex infection segregation of viral double-stranded and singlestranded dna molecules in nuclei of adenovirus infected cells as revealed by electron microscope in situ hybridization replicating single-stranded adenovirus type dna molecules accumulate within well-delimited intranuclear areas of lytically infected hela cells distribution of viral rna molecules during the adenovirus type infectious cycle in hela cells rearrangements of intranuclear structures involved in rna processing in response to adenovirus infection adenovirus infection induces rearrangements in the intranuclear distribution of the nuclear body-associated pml protein deletion of the fiber gene induces the storage of hexon and penton base proteins in pml/sp -containing inclusions during adenovirus infection tatabinding protein and tbp-associated factors during herpes simplex virus type infection: localization at viral dna replication sites quantitative analysis of the hepatitis c virus replication complex intranuclear localization of herpes simplex virus immediate-early and delayed-early proteins: evidence that icp is associated with progeny virus dna the discovery and characterization of mimivirus, the largest known virus and putative pneumonia agent the vaccinia virus f r protein interacts with actin autophagosomes: biogenesis from scratch? tobacco mosaic virus infection induces severe morphological changes of the endoplasmic reticulum sequence of morphological changes in epithelial cell cultures infected with poliovirus temperature-sensitive vaccinia virus mutants identify a gene with an essential role in viral replication vaccinia virus nonstructural protein encoded by the a r gene is required for formation of the virion membrane characterization of the ul gene product of herpes simplex virus the vaccinia virus -kda protein forms a stable complex with the p a/ a major core protein early in morphogenesis endoplasmic reticulum-golgi intermediate compartment membranes and vimentin filaments participate in vaccinia virus assembly cytopathogenic effect of poliomyelitis viruses 'in vitro' on human embryonic tissues the nd component promyelocytic leukemia protein relocates to human papillomavirus type e intranuclear inclusion bodies in cultured keratinocytes and in warts african swine fever virus structural protein p is essential for the recruitment of envelope precursors to assembly sites african swine fever virus pb l protein is a flavin adenine dinucelotide-linked sulfhydryl oxidase putative site for the acquisition of human herpesvirus virion tegument cytopathic effect in human papillomavirus type -induced inclusion warts: in vitro analysis of the contribution of two forms of the viral e protein polyhedrin structure migration of mitochondria to viral assembly sites in african swine fever virus-infected cells replication of african swine fever virus dna in infected cells the herpes simplex virus rna binding protein us is a virion component and associates with ribosomal s subunits regulated cleavages at the west nile virus ns a- k-ns b junctions play a major role in rearranging cytoplasmic membranes and golgi trafficking of the ns a protein characterization of the vaccinia virus a r protein and its role in virulence functional analysis of adenovirus protein ix identifies domains involved in capsid stability, transcriptional activity, and nuclear reorganization adenovirus protein ix sequesters host-cell promyelocytic leukaemia protein and contributes to efficient viral proliferation a cellular factor is required for transcription of vaccinia viral intermediate-stage genes african swine fever virus is wrapped by the endoplasmic reticulum cellular copii proteins are involved in production of the vesicles that form the poliovirus replication complex vaccinia virus membrane proteins p and p are cotranslationally inserted into the rough endoplasmic reticulum and retained in the intermediate compartment daxx: death or survival protein? properly folded nonstructural polyprotein directs the semliki forest virus replication complex to the endosomal compartment viral rna replication in association with cellular membranes accumulation of virion tegument and envelope proteins in a stable cytoplasmic compartment during human cytomegalovirus replication: characterization of a potential site of virus assembly the vaccinia virus a l protein is needed for the microtubule-dependent transport of intracellular mature virus particles poliovirus infection and expression of the poliovirus protein b provoke the disassembly of the golgi complex, the organelle target for the antipoliovirus drug ro- infection with foot-and-mouth disease virus results in a rapid reduction of mhc class i surface expression monoclonal antibodies specific for african swine fever virus proteins vaccinia virusinduced microtubule-dependent cellular rearrangements cellular origin and ultrastructure of membranes induced during poliovirus infection cytoplasmic organization of poxvirus dna replication a positive-strand rna virus replication complex parallels form and function of retrovirus capsids alternate, virusinduced membrane rearrangements support positive-strand rna virus genome replication expression of the vaccinia virus a . l redox protein is required for virion morphogenesis the interaction of mammalian reoviruses with the cytoskeleton of monkey kidney cv- cells colocalization and membrane association of murine hepatitis virus gene products and de novo-synthesized viral rna in infected cells mechanism of virus occlusion into a-type inclusion during poxvirus infection autophagy in health and disease: a double-edged sword major and minor capsid proteins of human polyomavirus jc cooperatively accumulate to nuclear domain for assembly into virions immunofluorescent localization of double-stranded rna in reovirus-infected cells rotavirus replication: plus-sense templates for double-stranded rna synthesis are made in viroplasms rotavirus glycoprotein nsp is a modulator of viral transcription in the infected cell proteolytic processing in african swine fever virus: evidence for a new structural polyprotein pp mouse hepatitis virus replicase proteins associate with two distinct populations of intracellular membranes break ins and break outs: viral interactions with the cytoskeleton of mammalian cells ultrastructure and origin of membrane vesicles associated with the severe acute respiratory syndrome coronavirus replication complex assembly of vaccinia virus revisited: de novo membrane synthesis or acquisition from the host? assembly of vaccinia virus: incorporation of p and p into the membrane of the intracellular mature virus microtubule-mediated transport of incoming herpes simplex virus capsids to the nucleus adenovirus infection targets the cellular protein kinase ck and rna-activated protein kinase (pkr) into viral inclusions of the cell nucleus selection for temperature-sensitive mutations in specific vaccinia virus genes: isolation and characterization of a virus mutant which encodes a phosphonoacetic acid-resistant, temperature-sensitive dna polymerase vimentin rearrangement during african swine fever virus infection involves retrograde transport along microtubules and phosphorylation of vimentin by calcium calmodulin kinase ii micromorphology of fl cells infected with polio and coxsackie viruses remodeling the endoplasmic reticulum by poliovirus infection and by individual viral proteins: an autophagy-like origin for virus-induced vesicles characterization of the african swine fever virion protein j l vaccinia virus a l protein is required for association of viral membranes with dense viroplasm to form immature virions vaccinia virus g l protein interacts with the a l protein and is required for association of viral membranes with dense viroplasm to form immature virions a complex of seven vaccinia virus proteins conserved in all chordopoxviruses is required for the association of membranes and viroplasm to form immature virions evidence for an essential catalytic role of the f protein kinase in vaccinia virus morphogenesis physical and functional interactions between vaccinia virus f protein kinase and virion assembly proteins a and g external scaffold of spherical immature poxvirus particles is made of protein trimers, forming a honeycomb lattice the herpes simplex virus ul gene is required for localization of capsids and major and minor capsid proteins to intranuclear sites where viral dna is cleaved and packaged proteomics of herpes simplex virus replication compartments: association of cellular dna replication, repair, recombination, and chromatin remodeling proteins with icp herpes simplex virus replication compartments can form by coalescence of smaller compartments recognition of the adenovirus type origin of dna replication by the virally encoded dna polymerase and preterminal proteins induction of intracellular membrane rearrangements by hav proteins c and bc vaccinia virus dna replication occurs in endoplasmic reticulum-enclosed cytoplasmic mini-nuclei frog virus morphogenesis: effect of temperature and metabolic inhibitors subcellular distribution of the major immediate early proteins of human cytomegalovirus changes during infection herpes simplex virus type capsids transit by the trans-golgi network, where viral glycoproteins accumulate independently of capsid egress architecture of the flaviviral replication complex. protease, nuclease, and detergents reveal encasement within double-layered membrane compartments the vaccinia virus c and a-type inclusion proteins are specific markers for the intracellular mature virus particle alfalfa mosaic virus replicase proteins p and p interact and colocalize at the vacuolar membrane orf a-encoded replicase subunits are involved in the membrane association of the arterivirus replication complex localization of mouse hepatitis virus nonstructural proteins and rna synthesis indicates a role for late endosomes in viral replication immunolocalization of vaccinia virus structural proteins during virion formation identification and localization of genetic material of african swine fever virus by autoradiography identification and characterization of the ul gene product of herpes simplex virus type production of infectious hepatitis c virus in tissue culture from a cloned viral genome visualization and characterization of the intracellular movement of vaccinia virus intracellular mature virions vaccinia virus intracellular movement is associated with microtubules and independent of actin tails a novel herpes simplex virus gene, ul . , maps antisense to the ul gene and encodes a protein which colocalizes in nuclear structures with capsid proteins assemblons: nuclear structures defined by aggregation of immature capsids and some tegument proteins of herpes simplex virus maintenance of golgi structure and function depends on the integrity of er export identification of nuclear export signal in ul protein of herpes simplex virus type the vaccinia virus i l gene product is localized to a complex endoplasmic reticulum-associated structure that contains the viral parental dna a proline-rich region in the coxsackievirus a protein is required for the protein to inhibit endoplasmic reticulum-to-golgi transport effects of picornavirus a proteins on protein transport and gbf -dependent cop-i recruitment a viral protein that blocks arf -mediated cop-i assembly by inhibiting the guanine nucleotide exchange factor gbf proteins c and ns b of the flavivirus kunjin translocate independently into the nucleus ultrastructure of kunjin virus-infected cells: colocalization of ns and ns with doublestranded rna, and of ns b with ns , in virus-induced membrane structures localization of p , retinoblastoma and host replication proteins at sites of viral replication in herpes-infected cells aggresomes and autophagy generate sites of virus replication a decade of advances in iridovirus research macromolecular synthesis in cells infected by frog virus . xi. a ts mutant of frog virus that is defective in late transcription relationship between rna polymerase ii and efficiency of vaccinia virus replication virus assembly in hincksia hincksiae (ectocarpales, phaeophyceae) an electron and fluorescence microscopic study assembly of a large icosahedral dna virus, mclav- , in the marine alga myriotrichia clavaeformis (dictyosiphonales, phaeophyceae) a myristylated membrane protein encoded by the vaccinia virus l r open reading frame is the target of potent neutralizing monoclonal antibodies subcellular localization, stability, and trans-cleavage competence of the hepatitis c virus ns -ns a complex expressed in tetracycline-regulated cell lines vaccinia virus late transcription is activated in vitro by cellular heterogeneous nuclear ribonucleoproteins characterization of the ul gene product of herpes simplex virus type the vaccinia virus a l gene encodes a membrane protein required for an early step in virion morphogenesis localization of an arenavirus protein in the nuclei of infected cells enzymatic and control functions of reovirus structural proteins nuclear localization of a double-stranded rna-binding protein encoded by the vaccinia virus e l gene characterization of an early gene encoding for dutpase in rana grylio virus assembly of complete, functionally active herpes simplex virus dna replication compartments and recruitment of associated viral and cellular proteins in transient cotransfection assays robust hepatitis c virus infection in vitro the coronavirus replicase: insights into a sophisticated enzyme machinery key: cord- -c lszcu authors: miao, faming; zhang, jingyuan; li, nan; chen, teng; wang, lidong; zhang, fei; mi, lijuan; zhang, jinxia; wang, shuchao; wang, ying; zhou, xintao; zhang, yanyan; li, min; zhang, shoufeng; hu, rongliang title: rapid and sensitive recombinase polymerase amplification combined with lateral flow strip for detecting african swine fever virus date: - - journal: front microbiol doi: . /fmicb. . sha: doc_id: cord_uid: c lszcu african swine fever virus (asfv), the etiological agent of african swine fever (asf), a hemorrhagic fever of domestic pigs, has devastating consequences for the pig farming industry. more than , , pigs have been slaughtered since august in china. however, vaccines or drugs for asf have yet to be developed. as such, a rapid test that can accurately detect asfv on-site is important to the timely implementation of control measures. in this study, we developed a rapid test that combines recombinase polymerase amplification (rpa) of the asfv p gene with lateral flow detection (lfd). results showed that the sensitivity of recombinase polymerase amplification with lateral flow dipstick (rpa-lfd) for asfv was copies per reaction within min at °c. the assay was highly specific to asfv and had no cross-reactions with other porcine viruses, including classical swine fever virus (csfv). a total of field samples were examined using our method, and the agreement of the positive rate between rpa-lfd ( / ) and real-time pcr ( / ) was %. overall, rpa-lfd provides a novel alternative for the simple, sensitive, and specific identification of asfv and showed potential for on-site asfv detection. african swine fever (asf) is a severe viral disease that manifests clinical symptoms of hemorrhagic fever caused by african swine fever virus (asfv) and can result in case fatality rates of up to % in domestic pigs, depending on the virus strain (galindo and alonso, ) . asf, which was first identified by montgomery ( ) in kenya in the s, made its first incursion into europe via two successive entries into portugal (in and again in ) , spreading rapidly throughout western europe and then to south america and the caribbean (michaud et al., ) . it was eventually eradicated by the mid- s, with the exception of sardinia (mur et al., ) . however, since the second major incursion of the disease, initially into georgia in , asf has spread to eastern europe and russia (rowlands et al., ; revilla et al., ) . the virus has continued to spread worldwide, including china. since the first asf case emerged in china in august , more than cases have been recorded in provinces (zhou et al., ) . african swine fever normally presents with non-specific symptoms, including fever, anorexia, vomiting, and diffused hemorrhage in superficial skin. post-mortem examination shows pericardial effusion, kidney enlargement, lymphadenectasis, and darkened and enlarged spleen. all these features are indistinguishable from those seen in classical swine fever virus (csfv) infection (tauscher et al., ; li and tian, ) . at present, no effective treatment or vaccine for asfv is available, and disease control is based mainly on animal slaughtering and strict sanitary measures (cisek et al., ; rock, ) . rapid laboratory diagnosis is important for timely triage and confirmation to control and preventing this disease because of its rapid progression to death and spread. molecular tools based on the detection of the genetic information of asfv have become more widely accepted for asf diagnosis (oura et al., ) . polymerase chain reaction (pcr) and real-time pcr techniques have provided a supportive method to post-mortem asf diagnosis (aguero et al., ; zsak et al., ; fernandez-pinero et al., ) ; however, they cannot be used for field (on-site) detection in pig farms. recently, liu et al. ( ) reported that the improved realtime pcr assay using a universal probe library (upl) probe could be applied to asfv molecular diagnosis under field conditions. due to limitations of the battery-powered realtime pcr instrument, it can process only a moderate number of samples. isothermal recombinase polymerase amplification (rpa) has been successfully used to detect multiple viral pathogens, including infectious bovine rhinotracheitis virus (hou et al., ) , bovine coronavirus (amer et al., ) , ebola virus (yang et al., ) , bovine viral diarrhea virus, or foot-and-mouth disease virus (wang et al., ) . as reports of asfv detection by rpa are limited, we aimed to develop and evaluate a rapid detection tool that combines immunochromatographic strip tests, more commonly referred to as lateral flow devices (lfds), with rpa targeting the conserved asfv p gene. this study was conducted as part of the surveillance of the asf outbreak in china. samples were collected for asf testing and surveillance under the agreement between the ministry of agriculture and rural affairs of the chinese government and farm owners. sample collecting treatment was conducted in accordance with the protocols for viral hemorrhagic fever under the urgent interim guidance for case management established by the world organization for animal health. the protocol for this study was approved by the ethics committee of the military veterinary research, academy of military medical sciences. samples were collected by animal centers for disease control and prevention of jilin province. the viruses were inactivated in the bsl- lab, and the inactivated samples were transferred to the bsl- lab for genomic dna extraction and detection. for standard plasmids, a plasmid extraction kit was used in accordance with the manufacturer's instructions (axygen, united states). for field samples, tissue homogenates were prepared in formaldehyde, and the inactivated virus homogenate was subjected to dna extraction by using a nanomagnetic bead adsorption kit (bailing biotechnology, beijing co., ltd., china). for the whole extraction procedure, lysis, adsorption, and washing were performed, and elution with µl of rnase-free water was conducted to dissolve the dna. the extracted dna was then stored at − • c. the p gene was first amplified in the rpa reaction system comprising the designed primers (labeled biotin) and a -carboxyfluorescein (fitc) labeled-probe, and the expected amplicons were labeled with -fitc and -biotin at the ends. then, the amplified products were recognized by anti-biotin and anti-fitc monoclonal antibodies on the test line, where gold nanoparticles were prefixed (figure ) . the whole genome sequence of a p genotype ii virus-asfv-sy , which was sequenced in our lab (genbank accession number mh )-was used as the reference sequence for rpa primer selection. rpa sense primer ( -aagaagaaagttaatagcagatgccgataccac- ), rpa anti-sense primer ( -biotin-gctcttacatacccttccacta cggaggcaatg- ), and rpa probe primer ( -fam-tgg gttggtattcctcccgtggcttcaaagcaaag[thf]taa tcatcatcgcac-p- ) were designed by using twistdx nfo rpa kits (cambridge, united kingdom) in accordance with the manufacturer's guidelines. taqman pcr was performed to detect asfv p in an mx p multiplex quantitative pcr system (stratagene) in accordance with the manufacturer's instructions. real-time pcr primers for p were used as described before (king et al., ) . the sequences spanning the rpa amplification region were obtained through pcr and cloned into the pmd -t plasmid to generate figure | schematic of rpa-lfd assay. frontiers in microbiology | www.frontiersin.org pmd -p . taqman runs of the experimental samples involved at least three replicates with no-template or no-primer control and the combination of the primers. the pcr conditions were • c for min and cycles of • c for s and • c for s. a standard curve was generated from serially diluted p recombinant plasmids of known copy numbers. a pair of primers and rpa probe primer was designed to specifically detect asfv circulating strains in china. the rpa assay was conducted in a µl system by using a twistamp nfo kit (twistdx tm , cambridge, united kingdom). all the reagents ( nm rpa primers, nm rpa probe, × rehydration buffer, and purified h o) except the template or the sample dna and magnesium acetate were prepared in a master mix, which was aliquoted into each tube of a . ml tube strip containing a dried enzyme pellet. magnesium acetate ( . µl) was pipetted slowly into the tube lids, and subsequently, µl of the sample dna was added to the tubes, the lids were closed, and magnesium acetate was centrifuged into the tubes by using a mini-spin centrifuge. the tubes were immediately used for isothermal amplification. asfv-rpa detection was combined with an lfd (yoshida, co., ltd., china). then, µl of the amplified product was added to the sample pad, and the dipstick was inserted into µl of the sample buffer for - min. a dilution range of to copies per reaction of pmd -p recombinant plasmid was used to evaluate the sensitivity of recombinase polymerase amplification with lateral flow dipstick (rpa-lfd), and the amplicons were evaluated through agarose gel electrophoresis. the reactions were evaluated with prrsv/ch r, csfv/shimen, prv/jl , jev/sa - - , pedv/cv , and pcv b-sd to examine the specificity of the developed rpa-lfd assay. the thermo-reaction procedures were optimized after different primers, probe combinations, and thermo-cycles were run in the real-time pcr system to evaluate the sensitivity of taqman asfv real-time pcr assay. the real-time pcr conditions that yielded the highest amplification efficiency were • c for min and cycles of • c for s and • c for s by using the primer combination reported by king et al. ( ) . the realtime pcr assay was sufficiently sensitive to detect copies per reaction (figure ) . no cross-reactions with prrsv/ch r, csfv/shimen, prv/jl , jev/sa - - , pedv/cv , and pcv b-sd were observed, and a positive signal was detected in asfv-sy and asfv-jl . in this study, copies of the asfv-positive pmd -p plasmid were used as a template to determine the optimal rpa reaction temperature. the reaction mixture was incubated at eight different temperatures ( • c, • c, • c, • c, • c, • c, • c, and • c) for min. the detection result showed that the test line was short at • c and • c, and the test line density did not enhance significantly from • c to • c ( figure a) . in this study, copies of the asfv-positive plasmid were used as a template to determine the optimal rpa reaction time. in figure b , the rpa assay tested positive for asfv in min. the measured dna band density revealed that the dna yield doubled after a reaction time of min and increased slightly after min. the intensity of the dna bands in agarose gel did not significantly change at reaction times of , , , and min. this finding indicated that the rpa reactions during the remaining parts of this study were completed after min. however, the false positive test lines appeared when the reaction time was more than min (invalid result). therefore, min was considered the optimum reaction time for the rpa-lfd assay, and the assay worked from • c to • c. in terms of convenience and safety, • c was chosen as the optimum reaction temperature. the sensitivity results showed that the detection limit of the asfv rpa-lfd assay was copies per reaction of the recombinant plasmid pmd -p . the amplicon in the asfv rpa-lfd assay ( bp) was also tested through subsequent visualization with % agarose gel-electrophoresis after purification, and the sensitivity of rpa based on gelelectrophoresis visualization was copies per reaction (figure ) . in terms of the specificity of asfv rpa-lfd assay, no cross-reactions with other important viruses of pigs were observed (figure ) , and this observation was confirmed by agarose gel electrophoresis. the samples included spleen samples and blood samples of animals (jilin cdc). of these samples, spleen tissues and blood samples were positive for asfv nucleic acid as detected by rpa-lfd. taqman real-time pcr showed that samples were positive. the rpa-lfd detection results were consistent with those of real-time pcr. rpa-lfd revealed that the samples showed a light test line and high cq values. of these samples, one tested sample, which showed with a short test line or no test line, was rotten, and the cq value in real-time pcr was , indicating weakly positive result. although the detection results between the two methods were consistent (table ) , the rpa-lfd assay was more rapid than real-time pcr. in particular, the whole rpa-lfd assay yielded results in min, whereas real-time pcr generated results approximately h later. the average time from symptom onset to outcome in asf is - days; however, the pig farms were usually in rural areas or even in a mountainous area far away from the city laboratory, which required more time for sampling and transportation. once diagnosis and timely treatment of suspected asf pigs is delayed, the risk of asf exposure to other pig farms was increased. in the current outbreak, laboratory testing with taqman real-time pcr is being widely used in affected areas. however, requirements-including a sophisticated thermocycler, complex sample treatment procedures, and expensive reaction instruments-have limited its applications in point-of-care testing (king et al., ) . different isothermal molecule amplification assays, including loop-mediated isothermal amplification assay (lamp) (james et al., ) , polymerase cross-linking spiral reaction (wozniakowski et al., ) , cross-priming amplification method (fraczyk et al., ) , chimeric dna/lna-based biosensor (biagetti et al., ) , and droplet digital pcr (wu et al., ) , have been developed as a rapid, simple, and cost-effective alternative to pcr-based molecule assay. rpa has several advantages. for example, initial heating for dna denaturation is not required, and test conditions ( • c within min) are easily implemented. lamp assay for asfv detection requires a long time ( min) and high temperature ( • c− • c) (james et al., ) . by comparison, rpa assay takes less than min at • c to complete. as such, rpa assay is simpler and more easily used than lamp assay. wang et al. ( ) reported the field validation of real-time rpa for asfv, although this technique can specifically detect asfv plasmid with a detection limit of dna copies per reaction. however, this detection assay is based on an expensive scanner device. detection methods for actual clinical samples have yet to be designed, so the application of this test to clinical samples is limited. gao et al. ( ) developed crosspriming amplification combined with immune-chromatographic strips for the rapid on-site detection of asfv, but its reaction conditions include min at • c and six primers for a reaction system, thereby causing non-specific amplification. the use of lateral flow assays combined with a monoclonal antibody against p protein of asfv can be used to detect p viral and recombinant protein or inactivated culture virus (sastre et al., ) ; however, the sensitivity of the assay is -fold lower than genomic amplification. recombinase polymerase amplification with lateral flow dipstick overcomes the technical difficulties posed by current amplification methods; for example, it operates at a low and constant temperature, does not require the thermal denaturation of templates, and does not rely on an expensive thermocycler (aguero et al., ) . in combination with a commercially magnetic nanobead-based dna extraction kit, this approach can be applied to on-site testing or rapid diagnosis under poorly equipped conditions. rpa is highly resistant to crude samples, suggesting that it can be used for on-the-spot field testing with crude nucleic acid extraction. in an rpa-nfo reaction system, nfo cleaves the primer of the probe at the thf position and effectively deblocks the probe, thereby generating a new hydroxyl group that can act as a primer for polymerase extension; thus, the probe is transformed into an extension primer with an increased specificity of amplification (james and macdonald, ) . the potential defect of rpa-lfd assay for asfv is that it may carry over contaminants in fields because its tube must be opened after amplification is completed. therefore, precautions should be taken. for example, reaction tubes should be carefully opened and closed, gloves should frequently be changed, the progress of pre-and post-rpa amplification should be separated, and reaction time should be shortened if possible. the replacement of dttp with dutp may help prevent such carryover contamination as demonstrated in other nucleic amplified system assays. in summary, we evaluated a rapid rpa-lfd test for the rapid diagnosis of asfv. the superior performance of rpa-lfd for asfv and its consistent detection results with those of real-time pcr indicated its appropriateness for laboratory diagnosis and that it has great potential for on-site testing of asfv circulating in china. the raw data supporting the conclusions of this manuscript will be made available by the authors, without undue reservation, to any qualified researcher. this study was conducted as part of the surveillance of the asf outbreak in china. samples were collected for asf testing and surveillance under the agreement between the ministry of agriculture and rural affairs of the chinese government and farm owners. sample collecting treatment was conducted in accordance with the protocols for viral hemorrhagic fever under the urgent interim guidance for case management established by the world organization for animal health. the protocol for this study was approved by the ethics committee of the military veterinary research institute, academy of military medical sciences. samples were collected by animals centers for disease control and prevention of jilin province. the viruses were inactivated in the bsl- lab, and the inactivated samples were transferred to the bsl- lab for genomic dna extraction and detection. highly sensitive pcr assay for routine diagnosis of african swine fever virus in clinical samples a new approach for diagnosis of bovine coronavirus using a reverse transcription recombinase polymerase amplification assay chimeric dna/lna-based biosensor for the rapid detection of african swine fever virus african swine fever virus: a new old enemy of europe molecular diagnosis of african swine fever by a new realtime pcr using universal probe library development of cross-priming amplification for direct detection of the african swine fever virus, in pig 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droplet digital polymerase chain reaction (ddpcr) for detection and investigation of african swine fever virus development and evaluation of a rapid and sensitive ebov-rpa test for rapid diagnosis of ebola virus disease emergence of african swine fever in china preclinical diagnosis of african swine fever in contact-exposed swine by a real-time pcr assay key: cord- - md om authors: meix-cereceda, pablo title: educational values in human rights treaties: un, european, and african international law date: - - journal: hum rights rev doi: . /s - - - sha: doc_id: cord_uid: md om while human rights treaties provide a formidable set of principles on education and values, domestic courts often tend to adjudicate claims in terms of local arguments for or against each particular educational practice. this article explores how international human rights law could inspire the interpretation of domestic law and educational practice, without neglecting specific cultural aspects. firstly, the article reviews the sociological debate on values in education and shows its importance for the legal discussion. secondly, some critical contestations of international cultural human rights are outlined, as well as certain arguments to justify the importance of this model. the study of international law follows: the un, the european court of human rights, and three relevant african charters, as well as every reference to education made by the african commission on human and peoples’ rights and by the african court is examined. lastly, a comparative section reveals a certain cultural commonality inspired by the un treaties, but also reflects some cultural and institutional differences between the european and the african regional systems. educational action in schools. botha ( , ) has advocated the importance of international law as a reference and inspiration for interpreting domestic law and practice on educational matters involving human rights. with regard to national legal systems, du plessis ( , and ) has pointed out the exemplarity of the preamble of the south african national education policy act of when it proclaims that "the education system must be transformed into one which serves the needs and interests and upholds the fundamental rights of all the people of south africa." nevertheless, the concrete result in each learner's education will vary according to a complex interaction of all the aforementioned factors. using a sculptural metaphor, constitutions and international human rights treaties would provide a sediment of values to the educational clay. however, this clay will be modeled, to a greater or a lesser extent, by the hands of all the aforementioned actors. the starting point of this piece is that education always implies the transmission of certain values which, nevertheless, are sometimes in a tension with each other or even contradict each other. therefore, the absorption of values in each learner's case is not easily controlled by one single force but is the result of many influences. the child's own freedom will in all probability play a major role in how these values intertwine and weigh on their moral decisions. the notion of human rights culture has been contested as reflecting a eurocentric philosophy of the individual. indeed, as stoppioni ( , ) has recently reminded, "the fundamental problem of the european conception of human rights would be to focus exclusively on the individual and to forget the group". a harsher critique considers that "'human rights' are, as such, a false ideological universality, which masks and legitimizes a concrete politics of western imperialism, military interventions and neocolonialism" (Žižek ) . these arguments criticize what bonfiglio ( ) has called "human rights colonialism," which the same author has sought to overcome by proposing an intercultural theory of human rights. from an african perspective, justice mokgoro ( , ) , of the constitutional court of south africa, has claimed the proximity between human rights and the traditional values of ubuntu, while acknowledging that the communal dimension of ubuntu could enrich the interpretation of western law. in this regard, she mentions in particular the following ideas: -the original conception of law perceived not as a tool for personal defense, but as an opportunity given to all to survive under the protection of the order of the communal entity -communalism which emphasizes group solidarity and interests generally, and all rules which sustain it, as opposed to individual interests, with its likely utility in building a sense of national unity among south africans -the conciliatory character of the adjudication process which aims to restore peace and harmony between members rather than the adversarial approach which emphasizes retribution and seems repressive. the lawsuit is viewed as a quarrel between community members and not as a conflict. the importance of group solidarity requires restoration of peace between them -the importance of public ritual and ceremony in the communication of information within the group -the idea that law, experienced by an individual within the group, is bound to individual duty as opposed to individual rights or entitlement. closely related is the notion of sacrifice for group interests and group solidarity so central to ubuntu(ism) -the importance of sacrifice for every advantage or benefit, which has significant implicants for reciprocity and caring within the communal entity even if they were not written apropos of education, these reflections seem especially relevant to the debate on educational values, in particular with respect to which values the school system ought to promote and the related problem of conflict and restorative justice in schools. the abovementioned critical views, however, cannot undermine the importance of international protection. as will be discussed especially in "african union: commonality and specificities", regional international bodies have both the necessary independence from states and the ability to deliver a relevant view in terms of idiosyncratic proximity. in addition, the lack of adequate solutions in certain domestic cases would prove the necessity of international protection for at least certain categories of subjects. this seems of particular relevance in the case of children, arguably the most vulnerable subjects of human rights. some examples from southern african domestic courts may be helpful to illustrate the latter claim. in some cases, national courts have selected international rulings that may be isolated in a court's body of case law or not applied as a meaningful precedent by the international court itself. for instance, in the arundel school case the constitutional court of zimbabwe ruled against the application of certain pupils who had been obliged to attend school prayer by the new headmistress. the pupils' parents, who were jehova's witnesses, had expressly declared their faith upon the application for admission of their children, and the children had been attending the school before the arrival of the new headmistress. despite the fact that the application had been filed by the parents, the constitutional court expressly declared the right to expel the pupils, which the school had not yet carried out. even more surprising, however, was the fact that the constitutional court based on the european court's reasoning in the case of valsamis of , which has been changed in more recent rulings on similar claims, such as the cases of folgerø ( ), zengin ( ), or yalçın ( ) (see below, "european court of human rights" for details). in other cases, national courts simply refrain from using international law as a source of inspiration, even when it could reinforce the authority of their own rulings. in this regard, the generally protective constitutional court of south africa rarely integrates arguments from international law when ruling on matters concerning children and education. in the case of the juma musjid primary school, the principle of the child's best interest was only discussed in terms of national constitutional law in spite of the importance that international law has in this field (see below "full development of the human personality and best interest of the child"). in this case, an eviction order was sought by the owner of the land where a school was based. the constitutional court mentioned certain international treaties and soft law on the right to education, and even a us supreme court ruling, but no international decisions by african or un bodies were considered. the constitutional court held that the kwazulu-natal high court had failed to take account of the interests of the learners and, instead, had simply "privileged the right to property over the learners' right to a basic education" (para ). nevertheless, the court considered that the children had been successfully accommodated by other schools and therefore ruled for the owners and granted the order of eviction. another important case from south africa concerned the pregnancy policies adopted by several schools. in the welkom and harmony high schools case, the constitutional court declared these policies unconstitutional for being contrary to a number of rights including non-discrimination, the right to education, and the respect of the child's best interest. as will be discussed below, the african commission on human and peoples' rights has often sought to convince states and schools of the need to ensure school attendance of girls in general, and very especially in the case of pregnancy. nevertheless, and despite a specific allegation by one of the parties, the constitutional court did not mention any rule of international law in its judgment. other situations and cultural practices may deeply affect the full development of children and their right to education, as demonstrated by the achpr's appeals against genital mutilation, child labor, child marriage, and other forms of denial of the right to schooling, as will be discussed in the following sections of this article. while it is difficult to conceive international remedies as a valid instance for reviewing every domestic ruling, they are certainly useful for both denouncing and inspiring educational and legal practice. state authorities-but also individualsshould take notice of the problems detected by international bodies and, with the help of available or new domestic remedies, gradually work toward the improvement of such problems in daily practice. in this regard, the article seeks to provide a comprehensive view of the educational values advanced in three international human rights jurisdictions: the un, the european court of human rights, and the african instruments. part of the elements protected by these jurisdictions is shared by the other systems, but each of them has developed certain specificities. concerning the latter, an effort has been made to examine every allusion to education made by the african court on human and peoples' rights (hereinafter african court) and the african commission on human and peoples' rights (hereinafter achpr). lastly, some comparative considerations on the three systems will be outlined. the universal declaration of human rights (hereinafter udhr) includes a remarkable set of educational values. they have been further developed by some of the major human rights treaties sponsored by the un. four kinds of values seem relevant in this regard. the "full development of the human personality" principle is expressly mentioned in art para of the udhr and has been adopted as the main goal of education by many treaties and even constitutions. in order to grasp the meaning of this principle, it may be worth exploring some interesting variations across different international treaties and declarations. in , years after the udhr, the declaration of the rights of the child would state that education "will promote (the child's) general culture, and enable him, on a basis of equal opportunity, to develop his abilities, his individual judgement" (principle ). this declaration acknowledged the relationship between a person's awareness of the world that surrounds them ("general culture") and the development of their personality both in terms of their talents ("abilities") and their moral sense ("individual judgment"). thirty years later, the convention on the rights of the child (crc) would rephrase and widen these ideas stating the following: (…) the education of the child shall be directed to: (a) the development of the child's personality, talents and mental and physical abilities to their fullest potential (…). the main purpose thus became the development of talents and abilities, both mental and physical, as part of the more complex concept of the "child's personality." the declaration, on the other hand, included what is nowadays considered the main goal that should guide not only education but generally any measure concerning children. indeed, after the abovementioned statement, principle went on as follows: the best interests of the child shall be the guiding principle of those responsible for his education and guidance; that responsibility lies in the first place with his parents. full development of the personality and a child's best interest thus appear clearly connected if we consider the udhr and the declaration of the rights of the child jointly. this connection may be useful in order to construe the principle of best interest in some difficult cases. indeed, when the declaration referred to the best interests adopted december unga res a(iii) (udhr). declaration of the rights of the child (proclaimed by the general assembly, resolution (xiv), a/res/ / , november ) (drc). convention on the rights of the child (adopted on november , entered into force september ) unts (crc) art para . of the child as "the guiding principle of those responsible for his education", it also specified that this responsibility lies "in the first place with his parents". this phrase certainly means that parents are, prima facie, considered the fittest to decide what that interest may be. nevertheless, there may be some cases where parents may not be able or willing to distinguish between their own interest or belief, on one hand, and the child's best interest on the other: child labor, underage marriage, female genital mutilation (girls' circumcision), or recruitment into militias are only some of the most dramatic examples. in these cases, it may be difficult to justify an intervention of public authorities based solely on the principle of "the child's best interest," as parents might claim that international law enables them "in the first place" to determine that interest in each case. nevertheless, a joint interpretation of this principle and the full development of the child's personality may prove useful in this regard. an individual's personality may keep developing through all stages of life, which means that full development is almost an ideal, or, from a legal perspective, a principle permanently subject to the possibility of progression. this seems even clearer in the case of a child. therefore, if a decision from the parents may pose a clear threat to the child's future development, intervention from public authorities would then be justified insofar as necessary (and not any further) to safeguard the child's future possibilities of personal development. another interesting variation can be found in the international covenant on economic social and cultural rights : (…) education shall be directed to the full development of the human personality and the sense of its dignity (…) human dignity has been considered as a single human right and as a theoretical foundation of the entire legal system (solozábal echavarría , and garcía guerrero and even of the state (häberle , ) . from a practical perspective, however, if a person's human rights are violated or even threatened, that person may in all probability not lead a decent life. this paragraph from the icescr hence reminds that the right to education is almost literally a "key right," which raises in children and adults awareness of their own dignity, and eventually allows them to fight for their rights by any means acceptable in their society. from an economic the african commission for human and peoples' rights (achpr) sent on march a letter of urgent appeal to the authorities of uganda "concerning alleged child labour in extractive industries, particularly gold mining." association pour le progrès et la défense des droits des femmes maliennes (apdf) and the institute for human rights and development in africa (ihrda) v republic of mali african court of human and peoples' rights may , especially paras - . in addition, the achpr's th activity report (of ) acknowledged that "in january , child marriage was declared illegal in zimbabwe by the constitutional court" (para .a.ix). the achpr's th activity report ( ) found positive developments for human rights in this regard in senegal and the achpr's th activity report (of ) in four states of the sudan. the achpr's th activity report ( ), para , denounced the situation in the republic of congo. perspective, education would allow individuals from poorer origins to improve their situation-which is often described with the "social lift" metaphor. these ideas can be summarized in the words of the committee on economic, social and cultural rights (cescr), which conceives education as "an empowerment right". one last important aspect that un-promoted treaties often link to full individual development is the "strengthening of respect for human rights and fundamental freedoms". this phrase is used to describe one of the two basic aims of education according to art para of the udhr (the other one being the full development of the human personality). the phrase between quotes has thus come to represent, in international legal terms, the effort of the society to create a conscience in the child. in this regard, an early but powerful wording can be found in the geneva declaration of the rights of the child: the child must be brought up in the consciousness that its talents must be devoted to the service of fellow men. it is however the convention on the rights of the child that enshrines the richest catalog of educational and developmental aims. from the perspective of this paper, there are at least two interesting references in its text. firstly, the convention's preamble reminds that the "child should be fully prepared to live an individual life in society". secondly, and elaborating on this idea, art para even claims that "the education of the child shall be directed to: (…) (d) the preparation of the child for responsible life in a free society (…)". two different aspects should be underlined here. on the one hand, this sentence reminds that the child is to be educated in order to become a healthy adult, which prevents exploitation and generally any abusive treatment, considering that a child is not yet an adult. but, on the other hand, the fact that the child will eventually develop into an adult also stresses the need to gradually promote a certain responsibility and maturity. therefore, education should prepare a child to live autonomously in a free society. preparing a child for freedom also means preparing it for responsibility, for making its own rules and taking its own decisions as a useful member of the society, to quote principle of the un declaration of the rights of the child. this link between individual development and respect for human rights paves the way for the second of the aims mentioned in the general international law. the second aim of education would be clearly political. with different variations, most of the texts include understanding, tolerance, and peace among their political aims for education. a good example can be found in art para of the udhr, according to which, education "shall promote understanding, tolerance and friendship among all nations, racial or religious groups, and shall further the activities of the united nations for the maintenance of peace". the promotion and maintenance of peace has been the most important principle of international law at least since the establishment of the united nations in (white , ) . it was enshrined in the charter of the united nations as the maintenance of "international peace and security". the reference to "understanding, tolerance and friendship among all nations, racial or religious groups" would enable the primary goal of maintaining peace. nevertheless, it can be seen as a more ambitious purpose, too. in this respect, it seems that the udhr expects, or even promotes, the emergence of a global society, which in turn would be expected to achieve much more than preventing its peoples from going to war against each other. over years later, the convention on the rights of the child would repeat and widen the ideals of the universal declaration in this respect. the reference to nations and racial and religious groups was then completed with the more flexible "friendship among all peoples, ethnic, national and religious groups and persons of indigenous origin." moreover, the equality of sexes also joined the previous understanding, peace and tolerance. it is probably needless to remind that between the udhr and the crc, the international convention on the elimination of all forms of racial discrimination and the convention on the elimination of all forms of discrimination against women had been adopted, putting these problems on the international agenda. international law thus acknowledges the importance that children are made aware of the society's complexity as part of their growth and education process, and of the need to respect and equally treat every individual regardless of their social circumstances. indeed, the relationship between human rights and education can be conceived in dialectic terms. in this regard, promoting human rights in education by celebrating difference could in turn make education a force for social cohesion and understanding. the school system could enhance the child's awareness of different cultural approaches to sensitive or controversial matters, bearing in mind the age and maturity of the learners. for instance, discussion could be encouraged on the role of religion in society, the importance of art, the relationship between freedom of speech and political correctness, environmental conscience, sex or drugs, to name but a few of these controversial matters. a number of authors have underlined these ideas by naming human rights education a human right itself (alfredsson , ; benedek , ) . despite the claim for universality of human rights and the importance of promoting mutual understanding, the social circumstances surrounding a child are also important for education, as the third aim from the un treaties conveys. charter of the united nations (adopted june , entered into force october ) (un charter) art para . international convention on the elimination of all forms of racial discrimination (adopted march , entered into force january ) unts . convention on the elimination of all forms of discrimination against women (adopted december , entered into force september ) unts . mittler ( , ) has developed a model of inclusive education. in his words, "inclusion implies a radical reform of the school in terms of curriculum, assessment, pedagogy and grouping of pupils. it is based on a value system that welcomes and celebrates diversity arising from gender, nationality, race, language of origin, social background, level of educational achievement or disability" (emphasis added.) the third kind of values that are found in most declarations and treaties have to do with what sociologists would call the "meso" or middle level of societies. international law thus reveals an awareness of the importance that intermediate bodies (groups) have in a person's life. the family-despite its diminishing size in many societies-is considered the main channel for the flow of values from the groups that make a society to the child. language, cultural values, and moral and religious references, as well as many other traditions, are gradually absorbed by the child in an environment of such high affectivity as the family. all of these ideas could be summarized as the protection of cultural pluralism in education. indeed, even a treaty as sparing in educational matters as the international covenant on civil and political rights includes a reference to religious and moral education, if only to proclaim the right of parents to ensure that such education is delivered "in conformity with their own convictions". nevertheless, it is very difficult to construe this principle as a right to ensure that any education involving moral or even religious contents can only be attempted in conformity with the convictions of families. the reasons would be twofold. on the one hand, the scope of contents potentially affected by moral or religious views is so wide that it would be practically impossible to carry out an institutionalized education. thus, equal access to formal education and other principles that are part of the right to education would be made void. on the other hand, the aforementioned principles of the full development of the human personality and the best interest of the child justify that certain contents of public interest be addressed in a non-indoctrinatory manner, even against parental wishes. sex education has frequently been a controversial matter, but teaching in certain languages in some parts of the world can be just as disputed. however, it is the crc that best captures the essence behind the need to ensure pluralism in education. in its preamble, the states parties acknowledge "taking due account of the importance of the traditions and cultural values of each people for the protection and harmonious development of the child". also, when discussing placement of the child outside its original family, art para mandates that "(…) due regard shall be paid to the desirability of continuity in a child's upbringing and to the child's ethnic, religious, cultural and linguistic background." moreover, art para .c places the following values among the aims of education: the development of respect for the child's parents, his or her own cultural identity, language and values, for the national values of the country in which the child is living, the country from which he or she may originate, and for civilizations different from his or her own (emphasis added). however, the importance of all these cultural values does not prevent art para from proclaiming "(…) the right of the child to freedom of thought, conscience and religion". we may inquire about the purpose of stressing cultural specificity in international human rights treaties. this does not seem an appropriate occasion for developing all the complexity of the tension between the universality of human rights and their implementation in different cultural environments. but it may be useful to point out a few considerations on the matter, in particular concerning the topic of this article. cultural traditions may have a great value in collective terms, for example as a way of preserving different valid approaches to the world and to mankind. according to the african court, culture should be construed in its widest sense encompassing the total way of life of a particular group, including the group's languages, symbols such as dressing codes and the manner the group constructs shelters; engages in certain economic activities, produces items for survival; rituals such as the group's particular way of dealing with problems and practicing spiritual ceremonies; identification and veneration of its own heroes or models and shared values of its members which reflect its distinctive character and personality. however, this does not appear as the main argument to ponder here. when discussing child education and values, other considerations seem to take precedence. the rights of parents to instill certain values and, generally, the protection of specific groups and their traditions find a strong justification in the need of a certain psychological stability of the child, a feeling of safety which is crucial for a healthy development of the young who will, over time, become adults. childhood, once again, is not only protected on account of its intrinsic value-which it clearly has, as the right to the child's freedom of conscience underlines-but also because it is the seed of tomorrow's adults that will shape society. a fourth kind of values, still not very common in international law on education, refers to a growing concern in other domains of international law. art para of crc shows this concern in the following terms: [states parties agree that the education of the child shall be directed to (…)] e. the development of respect for the natural environment. given the overwhelming scientific analyses that place human activity at the origin of global warming, and of air, water, and land pollution among many other environmental hazards, the fact that this fundamental value is mentioned as a goal of education in only one of the major conventions on human rights can only be received with surprise. nevertheless, it is a perfectly valid obligation under international law, enshrined in a treaty that is binding for states parties, three more than the member states of the united nations. the usa seems to be the only state not to have ratified or adhered to this convention (of which, however, it is a signatory). the european court of human rights (hereinafter ecthr) has produced approximately judgments and decisions on educational matters. concerning values in education, the court's rulings stem from the second sentence of article of the first additional protocol to the convention. this sentence reads as follows: in the exercise of any functions which it assumes in relation to education and to teaching, the state shall respect the right of parents to ensure such education and teaching in conformity with their own religious and philosophical convictions. in spite of this rather open wording, the ecthr has nevertheless managed to develop a rich case law. it is not possible to examine all of these rulings in detail or to discuss some of the ecthr's excesses. i will therefore limit the analysis to a broad summary of three principles before focusing on how they apply to human rights education, given its relevance for the discussion. firstly, the ecthr has displayed a rather extensive conception of the states' "margin of appreciation". this is especially true in matters of religious symbols, either personal (swiss teachers, turkish students, or french learners ) or institutional. among the latter, the italian "crucifix case" is widely known, but earlier rulings dealt with religious freedom and national celebrations in greek schools. secondly, the ecthr has frequently applied the "best interest of the child" doctrine whenever this interest could be endangered by parental religious or philosophical convictions: the abovementioned cases of kjeldsen and jiménez alonso, or the decision in the konrad v germany case, are some of the most prominent examples on sex education (the first two) and compulsory schooling (the third one). the best interest of the child principle, however, has occasionally been subordinated to a state's margin of appreciation whenever there has been a conflict between the two. for instance, a conflict between the best interest of the child and the french principle of secularism, or the italian defense of the crucifix, or the greek celebration of the national day. most of the cases mentioned in the previous paragraph exemplify this statement. a third group of cases has developed from . these rulings deal with indoctrination in the classroom. they address the instilment of certain religious values through specific ritual practices in compulsory classes for underage learners or a disproportionate attention to certain religious doctrines and a practical neglect of others. the ecthr has upheld the applicants in all such cases. human rights education (hre) was mentioned above as one of the key instruments for education to perform as an empowerment right (see above "promoting understanding, tolerance, and peace"). it can be provided as an autonomous subject or transversally through different subjects, or even as non-formal education. in some cases, however, a vivid controversy has been prompted by the introduction of a specific subject in the school system. this was the case of spain after , when the new subject on "education for citizenship and human rights" was denounced and legally challenged by the political opposition and the catholic church. the subject was deemed constitutional in a number of rulings by both the supreme court and the constitutional court, but the central claim of the opponents to the bill deserves some consideration nevertheless. according to this claim, the curriculum of the subject would have been indoctrinating because it reflected an intent of the state to instill certain moral values. in the opinion of the applicants, such an objective would be the prevalent responsibility of the families and therefore the state should refrain from interfering with it. while the highest domestic courts held that certain values could be legitimately taught by the school system, the case never reached the ecthr and hence the question may remain whether the spanish subject would have been sanctioned by the european court or, on the contrary, whether it would have been declared indoctrinating. however, the ecthr has delivered a number of rulings on the legitimacy of teaching values within the education system. in this respect, the abovementioned cases from norway and turkey are useful precedents. as explained, parts of the curricula in these cases were considered indoctrinating on account of the prevalence granted to certain religious beliefs and rites. interestingly, however, the ecthr made it clear that the teaching of values in school entails a valuable opportunity for young people to appreciate and respect difference and even to experience the commonality of many moral principles that underlie various systems of beliefs. concerning the spanish case, and given that no specific aspects of the curriculum had been challenged before the national courts, it seems arguable that the ecthr would have upheld the decision to introduce the education for citizenship and human rights subject. the misgivings of the applicants concerning the spanish subject stem perhaps from the understanding that state values essentially equal a particular government's values. nonetheless, this is precisely the boundary between acceptable hre and unlawful and indoctrinating ideological reeducation. openness and debate should be part of hre, and teachers should refrain from conveying their own views where the discussion goes beyond the common principles underlying society. this can certainly be a thin line and may not necessarily avoid the risk of complaints by specific parents, but a teacher or educator who adopts a meticulous and open approach would in all probability be in accordance with the view of the ecthr. human rights treaties fostered by the organization of african unity (oau) and its successor the african union (au) include certain interesting obligations from the perspective of values in education. in addition, the african commission on human and peoples' rights (hereinafter the achpr) has provided, and continues to do so, valuable resolutions and other soft law instruments as well as case-based decisions through its communications procedure. the achpr's activity reports are also an invaluable source of information to keep track of both "positive developments" and "areas of concern" for human rights in the continent. see n. and n. . case of folgerø, cit. (see n. ), para : "the intention was that the school should not be an arena for preaching or missionary activities but a meeting place for different religious and philosophical convictions where pupils could gain knowledge about their respective thoughts and traditions (…). in the view of the court, these intentions were clearly consonant with the principles of pluralism and objectivity embodied in article of protocol no. ". and para : "(…) from the drafting history it emerges that the idea was that the aim of avoiding sectarianism and fostering intercultural dialogue and understanding could be better achieved with an arrangement, such as here, bringing pupils together within the framework of one joint subject (...) moreover (…) the second sentence of article of protocol no. does not embody any right for parents that their child be kept ignorant about religion and philosophy in their education." a similar reasoning in paras & of the zengin case (see n. ). the key document of african instruments on human rights is the african charter on human and peoples' rights (hereinafter, african charter). provisions on education, however, appear scarce in the african charter, and there is only one specific reference on art para : "every individual shall have the right to education". apparently, and when compared to un provisions on education's goals and values, there is no reference to such values in the basic african instrument. nevertheless, it should be noted that article also refers to free participation in the community's cultural life as a right of every individual (para ) and to the duty of the state to promote and protect "morals and traditional values recognized by the community" (para ). this systematic proximity induces the consideration that education, participation in the community's cultural life, and the protection of moral and traditional (non-colonial) values are deeply connected in the african charter's spirit. this interpretation will be further discussed in "african morals, traditional values and cultures, and other specific political principles" below. in contrast to the african charter on human and peoples' rights, the african charter on the rights and welfare of the child displays a rich wording when dealing with educational values. this treaty has been so far ratified by states and signed by another five. only one state (morocco) has done neither. in addition, some provisions of the african charter on democracy, elections, and governance will be discussed. up to the present, states have become parties to it and fifteen others have become signatories. six states, however, have accomplished neither yet (botswana, egypt, eritrea, libya, morocco, and tanzania). let us now focus on the values that should guide education according to these three charters. although this fundamental aim does not differ in substance from the one set in the udhr and the core international human rights instruments, african instruments have included certain elaborations that deserve specific consideration. art para of the african child charter includes a phrase that is almost identical to another in the convention on the rights of the child, which seems a reasonable outcome given the proximity of their respective adoptions ( for the crc and for the acc). the first of the goals mentioned reads as follows: the promotion and development of the child's personality, talents and mental and physical abilities to their fullest potential. african charter on the rights and welfare of the child (adopted july , entered into force november ) (african child charter or acc). however, and beyond this initial commonality with un-fostered treaties, the african conception seems particularly concerned about the importance of education-and leisure (udombana )-for individual self-development in general and for promoting awareness of the own rights in particular. not by chance, in , the achpr identified among its "areas of concern" the fact that "many children are not in school despite the provision of free and compulsory education in some state parties, due to socio-cultural and political considerations, among others ; moreover, the achpr has included as a "positive development," among other measures taken to protect the rights of children, "the introduction of school feeding programs in south africa to encourage parents to send their children to school". as well as the fact that certain states "(…) have put in place educational systems that are specifically tailored to suit the mobile lifestyles of their indigenous populations/ communities (namibia) (…)". despite these achievements, certain "socio-cultural" patterns seem to hinder some specific groups, in particular women and girls. many examples can be found in the achpr's activity reports. among these, in , the special rapporteur on the rights of women in africa informed the commission that "the situation of women in the rural areas remains dire, and in the area of education, the problem of girls' access to education despite the progress made by some countries" (sic). more recently, the achpr intensified its appeal in order to denounce the "continuing discriminations and practices against women and girls, including the exclusion of pregnant girls from the education system and refusing them to take public examinations, which violates their right to education and serves to perpetuate other discriminations against them". in this regard, the achpr has also addressed letters of urgent appeal to certain governments that seemed to embrace these convictions, as revealed by "the statement made by the tanzanian authorities on june to the effect that pregnant girls and teen mothers would no longer be allowed to attend school and continue their education". fully aware of these hindrances, one of the most recent legal instruments in african human rights, the african charter on democracy, elections, and governance, directed its state parties "to provide free and compulsory basic education to all, especially girls, rural inhabitants, minorities, people with disabilities and other marginalized social groups", as well as to ensure "the literacy of citizens above compulsory school age, particularly women, rural inhabitants, minorities, people with disabilities, and other marginalized social groups". art of the acc refers to the right "to engage in play and recreational activities appropriate to the age of the child." see also n.j. udombana ( , ) . achpr, th activity report ( ), para .vii. emphasis added. achpr, th activity report ( ), p. , para v. emphasis added. achpr, th activity report ( ), para . achpr, combined nd and rd activity reports ( ), para . achpr, th activity report ( ), para .b.vi. emphasis added. achpr, rd activity report ( ). acdeg art para . acdeg art para . thus, an instrument apparently intended for political rights mandates the establishment of a free and compulsory education system and grants special attention to disadvantaged groups. nevertheless, it must not surprise that a charter on democracy, elections, and governance refers to education in such detail. to quote john dewey's classic book democracy and education, "the realization of a form of social life in which interests are mutually interpenetrating, and where progress, or readjustment, is an important consideration, makes a democratic community more interested than other communities have cause to be in deliberate and systematic education" (dewey , - ). more recently, and from the perspective another regional system for the protection of human rights, the inter-american court of human rights considered education as the "epitome of indivisibility and interdependence of all human rights". despite the political importance of education, however, complaints brought before the achpr through the communications procedure have often addressed insufficiency of funding or facilities, as well as a lack of dedicated teaching staff. so far, it may be concluded that african instruments on human rights consider the very accessibility to school education as a key element for the first value that should guide education: the full development of the child's personality. therefore, great interest is placed in countering social and cultural convictions that limit such accessibility. despite its clear connection with the previous aim, the importance that different african instruments attach to this matter recommends devoting a specific subsection to its discussion. after the development of the child's personality, the african child charter considers that education should be directed to: fostering respect for human rights and fundamental freedoms with particular reference to those set out in the provisions of various african instruments on human and peoples' rights and international human rights declarations and conventions the concept of education as an "empowerment right," already mentioned above, has been received in the african instruments on human rights. indeed, this idea was already present in the african charter despite the scarcity of its provisions on education. as such empowerment right, education helps the child-and future adult-to take informed decisions (thus increasing individual freedom) and live in better conditions (improving a certain equality and fostering solidarity). one specific example of better gonzales lluy and others v ecuador inter-american court of human rights series c no ( september ) para . see also hevia rivas ( , and , ) . socio economic rights and accountability project v. nig., comm. / , th achpr aar annex (may-nov ) . the complaint was declared inadmissible due to lack of proof concerning the exhaustion of domestic remedies. acc, art para .b. african charter, art : "state parties (…) shall have the duty to promote and ensure through teaching, education and publication, the respect of the rights and freedoms contained in the present charter (…)." living conditions would be "understanding of primary health care" (art para .e), which is of great importance given the threat of epidemics and viral infections in the continent (yellow fever, malaria, ebola, hiv, or the covid- pandemic). the wording of the acc, however, does not aim so much at raising awareness of the own human rights as it does at fostering respect for human rights. both aims (raising awareness and fostering respect) are not completely diverse, but the second might seem more ambitious. moreover, from a political perspective, democracy is enhanced if citizens are more and better educated, and in particular with regard to human rights. education on human rights and democracy (more commonly "human rights education") thus appears as a highly valuable resource. to be sure, the achpr has long been aware of its importance, as it showed with its resolution on human and peoples' rights education of and other statements. the member states of the african union have, for their part, displayed a clear interest in promoting this kind of education, as the african charter on democracy, elections, and governance demonstrates. according to this instrument, state parties undertake to implement programs and carry out activities designed to promote democratic principles and practices as well as consolidate a culture of democracy and peace. to this end, state parties shall: (…) . integrate civic education in their educational curricula and develop appropriate programs and activities. the importance of this obligation is further underlined by another provision. indeed, civic education shall be "systematic and comprehensive" and, more importantly, it shall aim "to encourage full participation of social groups with special needs in democracy and development processes". these provisions of the acdeg allow for three considerations. firstly, education is considered essential for the political participation of social groups (in this case, specifically those with special needs). once again, the idea of education as empowerment, now applied to groups with special needs. thus, the educational aim of fostering respect for human rights appears linked with the value of solidarity within society. secondly, the reference to "(social) groups" reminds of the abovementioned "intermediate bodies." among these, political parties are of particular importance in a parliamentary democracy. political parties, however, would be hardly democratic if their militants were unable to grasp the significance-and debate on the substance-of complex decisions advanced by their leaders. in a presidential democracy, the political resolution on human and peoples' rights education, adopted by the achpr at its th session, december . the text is available at https://www.ohchr.org/en/issues/education/training/compilation/pages/ resolutiononhumanrightseducation ( ) .aspx. in its th activity report, of , the achpr highlighted "lesotho's (…) new curriculum for schools which includes components of human rights issues affecting children." acdeg, art . emphasis added. acdeg, art para . party does not necessarily enjoy the same significance, but the education of those called to vote (especially a pluralistic and non-indoctrinating human rights education) remains of paramount importance. according to experts, "political representation means choosing, electing representatives, selecting the political class" (bonfiglio , ; similarly, randall , - ) , which confirms the importance of education as a crucial element for democracy. however, historically, in african politics, this has not excluded the possibility that the power of granting educational opportunities (e.g., through scholarships) was used, conversely, as an "enormously effective instrument of oneparty consolidation" (coleman and rosberg , ) or, more brutally, that teachers and health workers "were forced to attend political education meetings" under mugabe's rule in zimbabwe (laakso , ) . this confirms how strongly education can affect the political system. thirdly, the african conception of civic education appears in close connection with that of "development." if the notion of development may come as a novelty when discussing educational values, other principles deeply connected with it have been present in african human rights instruments since its early days. the ideas of independence, decolonization, and the highly interesting principle of african solidarity have more recently led to an emphasis on economic and social development. this, however, should not be deemed incompatible with the preservation of traditional values, territorial integrity, and african unity, as will be discussed below ("african morals, traditional values and cultures, and other specific political principles"). despite the strong connection of this principle with the full development of the personality, the authors of the african child charter have chosen to present it as a different goal. this principle is closely linked with the "universal" political aims of the core international human rights instruments as well. nevertheless, the preparation for responsible life in freedom does not only apply to children, but also to adults, and, importantly, even to those incarcerated. let us turn to the wording of the acc. its art para provides the following: the education of the child shall be directed to: (…) (d) the preparation of the child for responsible life in a free society, in the spirit of understanding, tolerance, dialogue, mutual respect and friendship among all peoples, ethnic, tribal and religious groups. while the general drafting and many of the elements appear very close, or even identical, to the relevant paragraph of the crc's, some differences should be underlined. the african wording thus features some new elements but, strangely enough, others have been erased. among the latter, "in the spirit of" the crc appeared see above "promoting understanding, tolerance and peace." achpr, st activity report (of ), para . crc, art para .d. see above "full development of the human personality and best interest of the child". the references to "peace," "equality of sexes," "friendship among all (…) national groups," and "persons of indigenous origin". the removal of the reference to national groups may be explained by the introduction, instead, of two new and more elaborate paragraphs on the matter (namely, e and f). however, the reasons behind the other three suppressions appear obscure, and the result, difficult to approve. the additions, nevertheless, enrich the text of the provision with some aspects of african legal and political thinking. perhaps the most evident would be the reference to "tribal" groups as a basic organizational form of many african societies, a notion criticized for the "lack of conceptual groundwork and empirical testing" on whether and how ethnicity affects voting preferences (elischer , ) . moreover, the ideas of "dialog" and "mutual respect" are also an important part of african culture, as the traditional notion of ubuntu expresses well (venter , and le roux , ) . as vervliet ( , ) has written, "in (…) ubuntu, the human person does not stand on his own, but becomes more human in relation with other people". lastly, the reference to the "peoples" is not an innovation of the african instrument, but it certainly acquires a new significance given the importance of this notion in the continent's legal tradition of human rights. it should be noted that the african charter, the achpr, and the african court on human and peoples' rights all bear the reference to the peoples in their very names, thus showing their importance as a subject of rights. human and peoples' rights thus appear closely connected in the african conception. unfortunately, the study of collective rights would require an in-depth approach that clearly exceeds the scope of this article. the un convention on the rights of the child referred to the development of respect for the child's "own cultural identity, language and values, for the national values of the country in which the child is living, the country from which he or she may originate, and for civilizations different from his or her own". receptive to the influence of its immediate un precedent, the african child charter picked up the baton and included four different provisions that expand these ideas. the relevant parts of art para mandate the following: the education of the child shall be directed to: (…) (c) the preservation and strengthening of positive african morals, traditional values and cultures; (…) (e) the preservation of national independence and territorial integrity; (f) the promotion and achievement of african unity and solidarity; article , in turn, further elaborates on the right to culture: state parties shall respect and promote the right of the child to fully participate in cultural and artistic life and shall encourage the provision of appropriate and equal opportunities for cultural, artistic, recreational and leisure activity. firstly, from the perspective of moral education, the acc is unorthodox but honest when it accepts that not all african morals, traditional values, and cultures are necessarily "positive" and hence deserve to be promoted. among the positive aspects, the abovementioned notion of ubuntu requires a socially valuable orientation of individual rights. in their definition of the african child, nthontho and ogina ( ) highlight the collective effort behind the education of the young. they illustrate this cultural pattern with the traditional saying that "it takes a village to raise a child". this communalist approach to human rights and education is genuinely african and is not to be found-at least not with the same intensity-in other conceptions. another example of traditional values inspiring human rights can be found in the south african constitutional court's ruling on the khosa case. according to kamga ( , ) , when the constitutional court held that "everyone's right to access social security encompasses permanent residents in the country" (including children), it was inspired by the values of ubuntu. on the other hand, a more negative aspect would be the use of corporal punishment. while it was banned by the south african schools act in , this ban was subsequently challenged by independent christian schools. the constitutional court, however, upheld the act in a memorable ruling by justice albi sachs. by limiting its advocacy to the positive inheritance, the acc separates itself from the wording of the older african charter, which did not include any differentiation but rather mandated the protection of any "morals and traditional values recognized by the community." still, despite the more advanced contents of the acc in this regard, basing on the african charter may include some advantages, too. an important one concerns the possibility of using the rather open communications procedure of article , thus attracting the attention of the achpr and, perhaps, driving it to use its "good offices" in search of a friendly settlement, or a recommendation, or even to submit the case to the african court. in this regard, certain complaints have been addressed to the achpr despite the strict wording of its article ("every individual shall have the right to education"). among these, for example, a case of concerning cameroon reflected an attempt by the complainants to demonstrate a linguistic, cultural, and educational undermining of the anglophone parts of the country by the government, thus trying to push the achpr to ponder on the argument of respect for cultural specificity and the protection of linguistic minorities. the achpr, nevertheless, rejected the complaint on article due to lack of sufficient proof (but accepted several others, including certain forms of discrimination such as that of the english language in business transactions ). the notion of culture, in the second place, is not only destined to the stationary status of preservation. the use of the term strengthening in art para .c and especially that of participation (linked in article with artistic and with recreational and leisure activities) bring the educational treatment of culture closer to its dynamic essence. education should help the children to understand and preserve their cultural heritage but also to enjoy and develop it. the african charter confirms this interpretation when it includes the right to "freely" "take part in the cultural life of his community" next to the very recognition of the right to education. thirdly, the references to "national independence," "territorial integrity," "african unity," and "african solidarity" are of a more political nature and reflect the historical circumstances to which the rise of the human rights movement in africa was bound. indeed, all of these ideas seem in line with the basic orientations of the organization of african unity since its inception. it should be interesting to remind that in , the african heads of states and governments declared themselves "determined to safeguard and consolidate the hard-won independence as well as the sovereignty and territorial integrity of our states, and to fight against neo-colonialism in all its forms". a purpose later reinforced in the preamble of the very african charter on human and people's rights, where the member states of the oau again showed themselves conscious of their duty to achieve the total liberation of africa, the peoples of which are still struggling for their dignity and genuine independence, and undertaking to eliminate colonialism, neo-colonialism, apartheid, zionism and to dismantle aggressive foreign military bases and all forms of discrimination, particularly those based on race, ethnic group, color, sex, language, religion or political opinions. summarizing, the protection of african cultural values in human rights' instruments reveals the struggle of the continent to become politically independent and economically developed while (dynamically) preserving the best of its traditional identity. one last aim of education according to the african child charter concerns the development of respect for the environment and natural resources. once again, the acc takes up the baton of the un convention on the rights of the child, until then the only un instrument on human rights to have mentioned environmental awareness as an educational value. given the rich resources of the african continent, also from an economic perspective, the african instrument expands the scope in order to instill respect for natural resources as well. indeed, natural resources have historically been over-exploited, either by colonial powers or under self-rule. the latter, nevertheless, were often responsible for some of the first conservation efforts as well (van eeden , ). african charter art para . organization of african unity charter, may , (oau charter) preamble. acc art para .g. c.w. de kiewiet ( , ) , in his history of south africa, wrote that "in all the great colonial regions of the world the history of the ruthless exploitation of natural resources is a full one." this provision, therefore, points to the aim of delivering the continent from economic exploitation. in doing so, it is perfectly coherent with the african charter's proud declarations that "all peoples shall freely dispose of their wealth and natural resources. this right shall be exercised in the exclusive interest of the people. in no case shall a people be deprived of it." some of the most infamous cases of recent history are closely linked with this defense of the environment against large transnational companies backed by some governments. the most notorious is probably the niger delta dispute, but the aforementioned achpr/kenya case concerning the rights of the ogiek community of the mau forest is a more recent example. both un and regional systems reflect certain humanistic values that, despite different wordings and circumstances, may be considered essentially common to all three conceptions. perhaps the best example is the principle of the full development of the personality (often linked with the child's best interest doctrine), but clearly not the only one. the promotion of understanding, tolerance, and of specific cultural values is also present in every human rights system. on the darker side, the risk of cultural indoctrination has made its appearance in both the european and the african contexts. despite these common aspects, regional systems also reveal specific conceptions that are due to each continent's own history and current challenges. in the african system, the different charters reflect a rather open understanding of cultural values and traditions by granting every individual the right to "freely participate" in cultural life. the historical struggle for political independence, economic development, and environmental protection has also left its mark on educational values. concerning the enforcement of the charters, however, the communications procedure before the achpr may only lead to the adoption of decisions that are technically not binding for the states parties involved. this lack of binding force when discussing individual communications may explain why certain statements throughout the achpr's periodical activity reports have adopted a strongly critical style, for example with regard to access to education for pregnant girls. a more frequent intervention of the african court might be desirable, but both the institutional framework and the system's budget entail limitations. the ecthr, on the other hand, may seem less demanding than the achpr in its requirements to states parties. examples of this are the frequent recourse to the margin of appreciation doctrine and the ecthr's acquiescence to france's broad interpretation of secularism or italy's defense of the crucifix as a symbol of universal values. however, this acquiescence in matters that are highly controversial within certain societies could paradoxically reflect a stronger institutional system and hence a smaller need to react to all challenges. this institutional strength (at least when compared to other human rights systems) arises from the solid position of the ecthr as the only international protector of the echr and from the mandatory nature of its rulings for the african charter art para . soc. and econ. rights action ctr. v. nig, comm. / , th achpr aar annex v ( - . states parties involved. nevertheless, and most importantly, the ecthr receives and adjudicates a far larger number of cases than any other human rights system. this grants the european court the opportunity to rule on each case considering the social, political, and legal specificity of the state concerned, rather than motivated by the need to develop a notion that is valid for the whole continent. it therefore seems to have more occasions to develop a nuanced body of principles. such a system, however, requires greater funding by states parties. the importance of international human rights law: contestations and reasons" and stoppioni protocol to the african charter on human and peoples' rights on the establishment of an african court on human and peoples' rights comm. / , th achpr aar annex the right to human rights education human rights education intercultural constitutionalism: from human rights colonialism to a new constitutional theory of fundamental rights in search of ways of curtailing aggression and violence in schools: a human rights-based approach la reproduction. Éléments pour une théorie du système d'enseignement. minuit, paris. english version ( ) as reproduction in education reprint ) democracy and education. forgotten books, london du plessis a ( ) school governance and management decentralisation and school autonomy in the south african education system. dissertation the emergence of decentralised-centralism in the south african education governance system political parties in africa. ethnicity and party formation tirant lo blanch, valencia glenn cl ( ) what is at stake in debates over education and religion verfassungsprinzipien als erziehungsziele die menschenwürde als grundlage der staatlichen gemeinschaft pobreza y derecho a la educación el derecho a la educación y la educación en derechos humanos en el contexto internacional education, social mobility and social reproduction in sweden: patterns and changes cultural values as a source of law: emerging trends of ubuntu jurisprudence in south africa insights into electoral violence in africa the concept of 'ubuntu': africa's most important contribution to multicultural education new york martín criado e ( ) la escuela sin funciones. bellaterra conceptualisation of an "african child" in the context of basic education in south africa political parties in africa and the representation of social groups dignidad de la persona stoppioni e ( ) some reflections on the human rights discourse in the eu-japan strategic partnership agreement. e-conference on eu-japan relations social rights are human rights: actualizing the rights to work and social security in africa history of south africa. from the distant past to the present day the notion of ubuntu and communalism in african educational discourse the human person. african ubuntu and the dialogue of civilisations keeping the peace. the united nations and the maintenance of international peace and security acknowledgments the author wishes to kindly thank prof johan beckmann, prof everard weber and dr. andré du plessis, from the university of pretoria's department of education management & policy studies. this research was made possible by the university of pretoria's visiting professors program. conflict of interest the author declares that he has no conflict of interest.publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. key: cord- -tp rgmv authors: zhu, yuan-shou; shao, ning; chen, jian-wei; qi, wen-bao; li, yang; liu, peng; chen, yan-jing; bian, su-ying; zhang, yan; tao, sheng-ce title: multiplex and visual detection of african swine fever virus (asfv) based on hive-chip and direct loop-mediated isothermal amplification date: - - journal: anal chim acta doi: . /j.aca. . . sha: doc_id: cord_uid: tp rgmv african swine fever is caused by african swine fever virus (asfv), and has a mortality rate approaching %. it has already caused tremendous economy lost around the world. without effective vaccine, rapid and accurate on-site detection plays an indispensable role in controlling outbreaks. herein, by combining hive-chip and direct loop-mediated isothermal amplification (lamp), we establish a multiplex and visual detection platform. lamp primers targeting five asfv genes (b l, b l, c r, d l, and g l) were designed and pre-fixed in hive-chip. on-chip lamp showed the limits of detection (lod) of asfv synthetic dnas and mock samples are and copies per microliter, respectively, and there is no cross-reaction among the target genes. the overall performance of our platform is comparable to that of the commercial kits. from sample preparation to results readout, the entire process takes less than min. multiplex detection of real samples of asfv and other swine viruses further demonstrates the high sensitivity and specificity of hive-chip. overall, our platform provides a promising option for on-site, fast and accurate detection of asfv. african swine fever (asf), caused by african swine fever virus (asfv), is a highly contagious and lethal disease which manifests the symptom of acute hemorrhagic fever in domestic pigs and wild boars [ ] [ ] [ ] . since asf was first reported in kenya in , it has rapidly spread around many countries of africa, europe, america and asia [ ] [ ] [ ] . in august , the first asf outbreak in china was identified in shenyang city, liaoning province and spread to many provinces in a fast way [ ] . by march , outbreaks were reported in provinces and about , , pigs have been culled to halt further expansion, posing a devastating impact on both local and the global swine industry [ ] . asfv is an enveloped double-stranded dna virus transmitted by soft ticks. asfv has a giant genome of - kb and possesses a multilayered structure and overall icosahedral morphology [ , ] . because of complex genetic composition and high variabilities, asfv is currently classified into genotypes and more subtypes [ ] . there is no effective treatment or vaccine available, thus early and accurate diagnosis of asfv is crucial for rapid control of outbreaks. more recently, by comparing the genome of asfv china/ /anhuixcgq strain and related european genotype ii strains, bao et al. found - variation sites contributing to the alteration of amino acid residues in - genes, which put forward the high requirements for accurate and mutation-tolerant detection [ ] . the current methods for asfv detection can be generally divided into two types: ) the immunology detection methods, including haemadsorption test (had) [ ] , enzyme-linked immunosorbent assay (elisa) [ ] , fluorescence antibody test (fat) [ ] , and lateral flow assay (lfa) [ ] . although had is reliable and effective, they often take several days to get the results and need high-quality tissues for preparing cells. elisa and fat are rapid and convenient methods for precisely recognizing viral antibodies, but this serological diagnosis may not suitable for accurate early diagnosis when there is very low level of asfv antibodies before seroconversion [ ] . ) the molecular biology detection methods, including many kinds of polymerase chain reaction (pcr) [ ] [ ] [ ] , invader assay [ ] , loop-mediated isothermal amplification (lamp) [ , ] , and recombinase polymerase amplification (rpa) [ ] . as a gold standard for asfv detection in the laboratory, pcr requires thermal cycling instruments and skilled operators, which is not ideal for j o u r n a l p r e -p r o o f resource-limited situations. with no need for well-equipped laboratory and professional operations, isothermal amplification has emerged as a promising on-site detection method. recently, a variety of novel isothermal amplification assays in combination with clustered regularly interspaced short palindromic repeats (crispr) and lateral flow assay (lfa) have been developed for asfv diagnosis [ ] [ ] [ ] [ ] . these methods achieved higher sensitivity and specificity, and could be adaptable for point-of-care testing (poct). nevertheless, the separation of amplification and detection in open space makes it possible to generate false-positive results due to aerosol contaminations. without amplification, a high-throughput detection system based on crispr-cas a is also established for asfv detection, but it is inconvenient to transfer the cas a-cleaved product from a water bath into a disposable cartridge for detection [ ] . last but not least, all methods aforementioned are usually focused on detecting only one gene target at a time, such as b l encoding viral protein p (vp ) [ ] [ ] [ ] [ ] [ ] [ ] , gl encoding sulfhydryl oxidase [ ] , p r encoding topoisomerase ii [ ] , or k r encoding dna binding protein p [ ] , which may lead to false-negative results because of possible mutations on the complex, highly variable genomes of asfv. for example, gallardo et al. found the oie (world organization for animal health)-recommended conventional pcr showed reduced sensitivity when detecting field and experimental samples because of the nucleotide mismatches between the primers and the asfv target gene [ ] . to sum up, the need for rapid, sensitive, integrated, and multiplex detection of asfv without thermal cycler has not yet been satisfied. one target gene for each pathogen, which may not suitable to accurately detect variable targets, such as the viral nucleic acid. herein, we provide a multiplex and visual detection platform based on capillary array and direct lamp for rapid and accurate detection of asfv. given the complex and variable properties of asfv genomes, we choose five conserved genes (b l, b l, c r, d l, and g l) as the target for detection, avoiding the false-negative results in virtue of the mutations of a certain gene. the profile of capillary array looks like a hive, so we named it "hive-chip". different sets of lamp primers are pre-fixed in each capillary. without nucleic acid extraction, naoh-treated swine blood sample is mixed with lamp reagents directly. due to the outer surface of the hive-chip is hydrophobic and the inner surface of the capillary is hydrophilic, lamp mixtures can be simultaneously loaded and dispersed into each capillary by capillary forces. then the hive-chip is incubated at for h with sealed optical film and the fluorescence signals are visually detected with nm uv-light. to our knowledge, there is no multiplex detection platform employing multiple targets presently available for asfv detection. hive chip-based multiplex detection platform greatly enhances detection accuracy and shows superior characteristics, such as high sensitivity, compatibility with isothermal amplification, on-site detection capability, thus possesses the potential to become a major platform for animal or zoonotic epidemics monitoring. fever regional laboratory, south china agricultural university (guangzhou, china). the genomic dna samples of other swine viruses, including dsdna virus prv (pseudorabies virus), ssdna virus pcv (porcine circovirus type ) and ppv (porcine parvovirus), are obtained from huazhong agricultural university (wuhan, china). according to the multiple sequence alignment of asfv china/ /anhuixcgq (genbank: mk . ) with other genotype ii asfv strains available in ncbi database, we chose five target genes (b l, b l, c r, d l and g l) based on the function type, conservation, and the length of sequences (data is partially shown in fig. s and table s ). meanwhile, we aligned two pairs of oie (world organization for animal health)-recommended pcr primers (i.e., oie-f/oie-r and ppa- /ppa- ) with the target sequence (data is shown in fig. s ). to screen more effective primers, we used primerexplorer v (http://primerexplorer.jp/e/) to design four primer sets for each target gene. all primers were synthesized by sangon biotech (shanghai, china). all gene fragments were synthesized and constructed into pmv vector by qinglan biotech (wuxi, china) . the plasmid of mutated b l gene was constructed using the quikchange site-directed mutagenesis kit (primers are listed in table s ). the procedure for fabricating the hive-chip mainly consists of three parts: the cleaning of capillaries, the assembly of hive-chip, and the super-hydrophobic modification. firstly, quartz capillaries with . mm outer diameter and . mm inner diameter were cut into mm sections (with a volume of ∼ . μl) by a diamond wire cutting machine. then the short capillaries were thoroughly cleaned with piranha solution (h so /h o = : , v/v) for at least . h, washed by pure water and ethanol, and dried in an oven. secondly, seven preprocessed capillaries were inserted into a pdms support to . mm deep as demonstrated in fig. , which carried ten arrayed through-holes and was modified by ultra-ever dry top coat. according to a previous study [ ] , the pdms support was made by a tubular mold with patterned columns of . mm diameter inside and cut to mm in length. thirdly, the j o u r n a l p r e -p r o o f super-hydrophobic modification was the key step for simultaneously sample loading. to be specific, μl ultra-ever dry top coat was loaded carefully on the top surface of the pdms support and the outer surfaces of the exposed part of capillaries. after that, the modified hive-chip was air-dried for use. all the lamp primer sets for asfv detection are listed in table s were also electrophoresed on a % agarose gel to generate the predicted fragments. on-chip lamp adopted the same reaction system as the protocol described above, except that bst dna polymerase was . × (namely . u μl − ) and no primers were added, because . μl of the primer set dissolved in . % chitosan was already individually pre-fixed in the corresponding capillary. one blank capillary with no primers were employed as the negative control (nc). to simultaneously introduce the lamp mixture into all seven capillaries, an adapter for sample loading was produced as our previously reported [ ] (fig. ) . the adapter had a funnel-shaped inlet connected with a shallow inverted dish, which could cover the exposed parts of all capillaries in the hive-chip. when the standard μl pipet tip was inserted into the inlet, the lamp mixture was gently injected and dispersed into all capillaries by capillary forces. then the adapter was removed with the locked tip and the plate well was absolutely sealed by an optical film. finally, the hive-chip was incubated at °c for less than min in an incubator and visually detected by a hand-held uv-light device. j o u r n a l p r e -p r o o f swine blood samples were collected in anticoagulant (edta-coated) tubes, followed by mixing of the samples with mm naoh in a ratio of : , with a final volume of μl, and incubation at room temperature for min [ ] . after that, μl of the mixture was pipetted into lamp reaction mixtures of μl for subsequent amplification. once the lamp reactions finished, the fluorescent images of the hive-chip were captured by a digital camera or a smartphone. for quantitative analysis, the fluorescent intensity data was extracted by genepix pro . software (molecular devices, ca, usa). signal intensity was set as mean of foreground subtracted by mean of background for each capillary. signal-to-noise ratio (snr) was defined as the ratio of signal intensity of the target to signal intensity of the negative control, and the cut-off was set as snr> . . triplicate tests were performed for samples to verify the reproducibility of the hive-chip. to optimize the detection procedure, a direct lamp method without nucleic acid extraction was adopted [ ] . as depicted in fig. , minimal operation and only steps are required. in the first step, swine blood samples were collected in anticoagulant tubes, followed by mixing of the samples with mm naoh in a ratio of : , and incubated at room temperature. the mixtures were directly used as the template for subsequent amplification. in the second step, the lamp reaction mixtures containing the pre-processed samples were injected into an inlet of the adapter that connects to the hive-chip. the mixtures could be uniformly dispersed into all capillaries by capillary forces. the adapter was then removed with the locked pipet tip and the plate was fully sealed by an optical film, providing a closed space for amplification and avoiding the aerosol contamination. in the third step, the lamp reactions were performed at °c for less than min in an incubator. the fluorescence signals of the amplifications were excited by a hand-held uv-light j o u r n a l p r e -p r o o f device and imaged by a digital camera or a smartphone for analysis. importantly, the entire process from sample collection to the readout of the results takes less than min. the genome comparison of a dominant strain of genotype ii asfv to design the optimal primer sets for lamp with high specificity, high sensitivity, and robust for a wide range of detections, we set several principles for target genes selection: ( ) since it is known that most of the variations among asfv genomes results from gain and loss of the mgf members [ ] , mgfs were excluded; ( ) the target genes were selected from different functional groups as diversified as possible; ( ) the length of the target genes was bigger than bp, the purpose is to ensure multiple sequence alignment to obtained conserved sequences in all known strains listed in genbank database. next, we performed a multiple sequence alignment analysis of all eligible genes and eventually chose five conserved genes for lamp primers design, including b l, b l, c r, d l and g l (data is partially shown in fig. s and table s ). although viral protein p (vp ) encoded by b l is the most frequently used gene target for asfv detection [ ] [ ] [ ] [ ] [ ] [ ] , many mutations are still found in different strains. besides, we also aligned two pairs of oie (world organization for animal health)-recommended pcr primers (i.e., oie-f/oie-r and ppa- /ppa- ) with the target sequence in b l and found many nucleotide mismatches (fig. s ) , which was consistent with the findings from other studies [ , ] . to avoid the possible false positive detection because of gene mutations in a single gene, it is necessary to perform multi-targets detection. to assure the success of obtaining optimal primer set, we designed four primer sets for j o u r n a l p r e -p r o o f each gene (table s and s ). evaluation of the primers were divided into two aspects: validity tests and specificity tests. two detection methods were used to analyze the lamp products: visual detection with fluorescent reagent and gel electrophoresis. for validity tests ( fig. a) , all four primer sets were effective in amplification of the target gene including b l, b l, d l and g l. both fluorescence detection and gel electrophoresis showed the positive reaction. but only one primer set could successfully amplify the target gene c r, in return, this prove the necessity of designing multiple sets of primers for a given target. overall, we obtained at least one set of effective lamp primers for each of the five asfv target genes. to access the specificity, every primer set was used to amplify all the five genes ( fig. b and table s ). the results clearly showed that only when a given set of primers and the corresponding template were added, expected signals were then observed for both fluorescent visual detection and gel electrophoresis, indicating that in-tube lamp was able to accurately and specifically identify the corresponding asfv targets. to verify the specificity on chip, lamp mixtures containing one of the five synthetic dnas were evenly distributed into capillaries of the hive-chip. further, we set an unrelated lamp primer set, which is specific for sad gene [ ] , as the positive control in each capillary array to demonstrate the validity of lamp reaction. all the results were as expected (fig. a) . for each synthetic dna, only the capillary containing the corresponding pre-fixed primers showed positive signals and the rest were negative. for example, for b l gene, apart from positive control (pc), the bright green signal was obtained only in capillary " " pre-fixed with the matched primers. similarly, the other four genes also showed specific amplification results, which were consistent with in-tube lamp reactions and demonstrated high specificity. to evaluate the sensitivity, five dna templates were mixed in one-pot and loaded at the same time, resulting in positive signals from all the capillaries with asfv primers in the hive-chip. as shown in fig. b , serially diluted dna mixtures including , , and copies per microliter were successfully detected. and a sensitivity of lower than copies per microliter was only achieved for the target j o u r n a l p r e -p r o o f genes c r and d l, so the limit of detection (lod) for the current hive-chip was around copies per microliter, i.e., copies per reaction. according to the oie (world organization for animal health) manual of standards for diagnostic test and vaccine [ ] and the validation of actual samples [ , ] , the sensitivity of oie-recommended pcr is about copies per reaction. in addition, copies per microliter of dna could be easily obtained from acute infection of asfv [ ] . these facts demonstrating that the sensitivity of hive-chip is suitable for asfv detection in real world. by optimizing the reaction conditions and lamp primers, we believe that higher sensitivity could be achieved for hive-chip. sample treatment is one of the key steps in nucleic acid testing (nat) systems. although nucleic acid extraction can provide high-quality and relatively pure templates for the down-stream analysis, it also complicates the procedure and enhances the risk of nucleic acid loss and cross-contamination, which is not suitable for point-of-care tests (pocts). to simplify nucleic acid extraction, liu et al. [ ] developed an accurate, rapid and easy-to-use snp detection method based on lamp that do not require dna extraction from whole blood, dried blood spot, buccal swab and saliva, this method is known as direct-lamp. according to their results, naoh treatment could effectively lead to cell lysis, followed by release of dna for use in lamp amplification. meanwhile, various dna polymerase inhibitors in whole blood, such as hemoglobin, igg and proteases can be inactivated by the treatment with naoh solution. to further verify the applicability of hive-chip, the best way is to test deactivated real sample in blood collected from asfv infected pigs. however, due to safety issue and highly restricted regulation of the government, it is very difficult to collect real samples. thus, we decided to mimic the real sample. we prepared a set of mock samples by spike all the five synthetic dna templates into edta-blood collected from a healthy pig. the dna templates were set as , , , , and copies per microliter. because asfv is a virus with dsdna genome, and the viral particle is very easily to be disrupted [ , ] , we believe these mock samples are very close to the real sample. by applying the mock samples, we conducted the entire analytical process from sample treatment to fluorescent readout in the hive-chip j o u r n a l p r e -p r o o f following the protocol shown in fig. . as what we expected, five genes were successfully detected from this blood sample at the low limit of detection (lod) of copies per microliter (fig. a) , which were comparable with the results acquired from the pure plasmid samples. the quantitative analysis of the signal intensity obtained from the corresponding hive-chip (e.g., copies and copies per microliter) further confirmed the reliability of results. it may due to the complex background of swine blood that a sensitivity of lower than copies per microliter was only achieved for the target gene b l, c r and d l. but from the perspective of detection, as long as the sensitivity of one gene reaches the lod, asf will not be missed. furthermore, to avoid that the complex background of swine blood would generate false-positive, we set the healthy blood sample with no target genes (namely copies per microliter) as a control. according to the results, no capillaries showed bright green fluorescence apart from positive control, which proved the capability of performing analysis of more complicated samples of asfv. to clearly display the linear detection ranges and detection limits of different genes, we also drew sensitivity plot for each gene (fig. b) . although the signal advancement of the hive-chip line charts exhibited positive correlated with the concentration of the targets, they did not show good linear relationship, this could be explained by the fact that lamp is intrinsically not a linear amplification method. the fluorescence of c r gene at copies per microliter was a little bit higher than that at copies per microliter, which might result from the fluctuation of low copies templates in complex background (fig. b) . although the relatively conserved sequence (e.g., b l) of asfv has been chosen for detection, we can still find that the mutable viral genomes bring many mismatches between the primers and the target sequence ( fig. s and s ) . to further prove that the detection performance of hive-chip was comparable with commercial kits, pcr kit and lamp kit (yoyoung biotech) approved by china animal disease control center for asfv detection were also tested using mock samples of serial dilutions. as shown in fig. s , the limit of detection (lod) of both pcr kit and lamp kit was about copies per reaction. by contrast, the sensitivity of hive-chip was copies per microliter, i.e., copies per reaction, which was comparable with that of these commercial kits. in addition, the sensitivity of our platform meets the international standard, i.e., the recommended oie manual of standards for diagnostic test and vaccine, i.e., approximately copies per reaction [ ] [ ] [ ] . as previously reported, zhao et al. [ ] adopted qpcr to quantify vp gene copies of the blood samples from three infectious pigs. after days infection, the vp gene copies can reach more than copies per milliliter (i.e. copies per microliter), which is far above the limit of detection of hive-chip. this also confirmed the practicability of our platform. actually, we can also increase the input of blood in the lamp mixtures to improve the sensitivity of detection when it is necessary. moreover, both oie pcr and commercial kits (yoyoung biotech) can only detect one gene (b l) at a time and require heavy instrumentation for fluorescence detection. while the lamp kit needs an extra incubation at °c for min for sample preparation to release the nucleic acids. in the contrast, our platform is capable of monitoring multiple targets in a single test. the results could be directly visualized, and no sophisticated sample preparation is needed. to further demonstrate the capability of hive-chip for asfv detection, we collected three asfv genomic dna samples in complex mixtures. as shown in fig. a , all of them were successfully detected by hive-chip. moreover, nine genomic dna samples of other major swine viruses, including pseudorabies virus (prv), porcine circovirus type (pcv ), and porcine parvovirus (ppv), were also obtained for specificity testing. as shown in fig. b and s , the assays exhibited no cross-reaction with asfv. these results indicate the high specificity of hive-chip. to clearly demonstrate the advantages of our platform, we prepared table s to compare hive-chip with other four representative methods for asfv detection, as well as two commercial kits. without nucleic acid extraction and heavy instrumentation, hive-chip can simultaneously detect five genes related to asfv in a one-pot reaction, which can largely guarantee the accuracy and avoid the aerosol contamination. the total testing time is less than min and the limit of detection (lod) is copies per reaction. moreover, compared with our previous work (table s ) , i.e., calm platform [ ] and paac system [ ] , the most important feature of current study is that we target multiple genes for a single pathogen (especially variable virus). to our knowledge, this concept has not been attempted for lamp and other isothermal nat technologies. meanwhile, direct-lamp was adopted to simplify the blood sample pre-treatment and facilitate the on-site detection of asfv. overall, we provided a total solution based on hive-chip for various targets and samples detection. multiplex nucleic acid detection of variable asfv is critical for accurate and early diagnosis of asf. however, current methods only target one gene of asfv, which easily brings missed inspection because of the highly mutable genomes of this virus. herein, we established a multiplex and visual detection platform based on hive-chip and direct lamp for rapid and accurate detection of asfv. this platform assured detection accuracy through monitoring several gene fragments in a single test. there are several advantages of our platform over the existing methods. firstly, the design of multi-targets detection in a single reaction plays a vital part in accurately diagnosis of the mutable viral nucleic acid. if we consider the singleplex detection as a "pistol" of shooting a target a time, hive chip-based multiplex detection platform may similar to a "shotgun", which can shoot many "enemies" (genes of asfv) a time. in this study, apart from the b l gene included in oie-recommended pcr, the other four conserved genes (b l, c r, d l and g l) are also selected as the target for the first time for multiplex detection of asfv, which largely avoid the false-negative results arising from the possible mutations of a certain gene. based on this principle, hive-chip can serve as a versatile platform for various virus detection. for example, nucleic acid testing (nat) of the recent outbreak of severe j o u r n a l p r e -p r o o f acute respiratory syndrome (sars)-cov- mainly covers orf ab gene, n gene, e gene and human rnase p gene as a control, which requires multiplex detection [ ] [ ] [ ] . in this case, hive-chip can integrate multiple genes at a time to realize simultaneous detection and subsequently save a lot of time for epidemic control. moreover, to our knowledge, it has not been reported that there is a significant difference in the expression level of these five genes in different strains of asfv. currently, asfv is usually genotyped using a combination of partial sequencing of the b l gene and analysis of the central variable region (cvr) of the b l gene [ ] . meanwhile, other genes like p , p , and cp l gene are also served as a supplementary classification standard [ ] . but it is hard to use the difference or ratio of these genes to identify the genotype of samples from different regions. secondly, multiplex nats are usually disturbed by cross reaction between different primer sets. hive-chip can provide physical isolation of primers by different capillaries, and the hydrophobic modification can avoid the cross contamination of capillaries in sample loading. meanwhile, the closed space for amplification and visual detection theoretically can prevent % aerosol contaminations. thirdly, nucleic acid extraction is the key step in nats and it often needs complex operation. integrated with direct lamp, the entire process of hive-chip from blood sample treatment to detection can be finished within min independent of nucleic acid extraction and sophisticated instruments, which is suitable for on-site detection of asfv. besides, other direct amplification methods including direct rpa [ ] could also be easily combined with our platform for different types of samples. last but not least, hive-chip based platform has good flexibility and compatibility. the current version of chip has ten channels for detecting as many as eight targets other than positive and negative control. as for asfv detection, we only adopt five targets and leave three channels unused. furthermore, by increasing the size of hive-chip, we can increase the channel number and locate more capillaries in a single hive-chip unit. because the current format of hive-chip is compatible with standard -well plate and it can be assembled into a single well, we can easily perform high-throughput sample loading by means of the multi-channel pipette [ ] . based on this, hive-chip can be integrated with the current automated liquid workstation (e.g., beckman & biomek ) for high-throughput sample loading. furthermore, to realize massive detection, we can also employ multi-mode plate reader system (e.g., biotek & cytation cell imaging multi-mode reader) to acquire fluorescence images for subsequent signal analysis. we believe that hive-chip-based platform is suitable for high-throughput screening when combined with widely accessible instruments of -well plate operation. unfortunately, due to the lack of biosafety laboratory for handling the infectious real samples, we didn't have chance to test swine blood sample obtained from pigs in summary, we have developed a multiplex visual detection method based on hive-chip and direct lamp with a streamlined operation procedure, which offers a feasible strategy and key reagents for rapid and accurate on-site detection of asfv. the method that we demonstrated is of high generality, it could be easily adopted for fast development of assays/ kits for animal diseases or possible future outbreaks. j o u r n a l p r e -p r o o f j o u r n a l p r e -p r o o f arrival of deadly pig disease could spell disaster for china african swine fever emerging in china: distribution characteristics and high-risk areas african swine fever virus: a review on a form of swine fever occurring in british east africa epidemiology of african swine fever virus interaction of historical and modern sardinian african swine fever viruses with porcine and wild-boar monocytes and monocyte-derived macrophages african swine 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detection from blood swabs highly sensitive pcr assay for routine diagnosis of african swine fever virus in clinical samples development of a novel quantitative real-time pcr assay with lyophilized powder reagent to detect african swine fever virus in blood samples of domestic pigs in china sensitive detection of african swine fever virus using real-time pcr with a ′ conjugated minor groove binder probe adaptation of an invader assay for the detection of african swine fever virus dna detection of african swine fever virus by loop-mediated isothermal amplification development of a real-time loop-mediated isothermal amplification (lamp) assay and visual lamp assay for detection of african swine fever virus (asfv) a recombinase polymerase amplification-based assay for rapid detection of african swine fever virus clustered regularly interspaced short palindromic repeats/cas -mediated lateral flow nucleic acid assay universal and naked-eye gene detection platform based on the clustered regularly interspaced short palindromic repeats/cas a/ a system crispr/cas a technology combined with immunochromatographic strips for portable detection of african swine fever virus cas a-based on-site and rapid nucleic acid detection of african swine fever high-throughput and all-solution phase african swine fever virus (asfv) detection using crispr-cas a and fluorescence based point-of-care system visual detection of multiple genetically modified organisms in a capillary array multiplex sample-to-answer detection of bacteria using a pipette-actuated capillary array comb with integrated dna extraction, isothermal amplification, and smartphone detection direct pcr amplification of forensic touch and other challenging dna samples: a review a direct isothermal amplification system adapted for rapid snp genotyping of multifarious sample types field-deployable viral diagnostics using crispr-cas african swine fever virus replication and genomics development of an updated pcr assay for detection of african swine fever virus african swine fever development of a taqman pcr assay with internal amplification control for the detection of african swine fever virus replication and virulence in pigs of the first african swine fever virus isolated in china detection of novel coronavirus ( -ncov) by real-time rt-pcr crispr-cas -based detection of sars-cov- highly accurate and sensitive diagnostic detection of sars-cov- by digital pcr genomic analysis of highly virulent georgia / isolate of african swine fever virus this work was partially supported by science and technology commission of key: cord- - gcmqh e authors: chiriboga, gonzalo; de la rosa, andrés; molina, camila; velarde, stefany; carvajal c, ghem title: energy return on investment (eroi) and life cycle analysis (lca) of biofuels in ecuador date: - - journal: heliyon doi: . /j.heliyon. .e sha: doc_id: cord_uid: gcmqh e in ecuador, the net energy contribution of biofuels is unknown or unnoticed. to address this issue, we determined the energy return on investment (eroi) for bioethanol and biodiesel. the selection of raw materials relied on their productive capacity, export and import records, and historical yields. consequently, the scope included three raw materials for ethanol (sugar cane, corn, and forest residues) and four for biodiesel (african palm, pinion, bovine fat, and swine fat). using a method based on the life cycle analysis (lca) of each biofuel, we assessed the entire production chain through statistical processing of primary and secondary information. then we calculated the calorific values in the laboratory, compared energy inputs/outputs, and finally obtained the energetic returns. erois for bioethanol were: . for sugarcane, . for corn, and . for wood. the results for biodiesel were: . for african palm, . for pinion, . for bovine fat, and . for swine fat. these values suggest feasibility only for sugarcane in the case of ethanol. in contrast, biodiesel has better prospects because all the feedstocks analyzed had erois higher than two. nevertheless, biodiesel is not available for trading in ecuador because energy policy has overlooked systems based on higher energy return. future studies should consider more comprehensive variables such as climate change, land use, and water management. globally, the use of biofuels in the transport sector increased % in (international energy agency, ). however, this growth was insufficient to achieve the international objectives set in the sustainable development scenarios for (united nations, ) , since this commitment would require tripling bioethanol and biodiesel content in final blends, involving around % of global transport (sawin et al., ) . several issues have slowed the incorporation of biofuels into worldwide transportation, for example, competition with the food sector for the use of feedstocks (ho et al., ) , the decrease in the calorific value due to the presence of oxygen (oh et al., ) , stillage handling and disposal (silva et al., ) , and the energy return on investment (eroi) (jessica g lambert, hall, balogh, gupta and arnold, ) . the eroi is directly or indirectly linked to the achievement of wellbeing, energy quality, and energy sovereignty (jessica g . it describes the amount of energy a source requires to deliver a unit of energy to society, and considers the energy flows involved in all stages of the production process . several methods for calculating the eroi have been published that contain points of agreement, but also methodological differences. the main disagreements relate to the way energy flows (moeller and murphy, ) , system boundaries, and residual energy embedded in co-products are identified and quantified (capell an-p erez, castro, javier and gonz alez, ) . the ecuadorean government has sought alternatives for reducing oil derivative imports to meet the local demand. these endeavors have intensified since last year, and in april , the ministry of agriculture announced the agrofuels plan, which would replace , ha of rice with sugar cane to produce bioethanol (el universo, ) . the program would also incorporate million liters of african palm oil per year to begin producing % v/v biodiesel (b ) (ministry of agriculture., ) (astm specification d , ). reducing imports would have a significant effect on ecuador's economy because, since the s, the country has maintained a subsidy on gasoline, diesel, and liquified petroleum gas (rivadeneira, ) . this public expenditure is increasingly unsustainable with demand increasing at around . % annually, fuel migrating to other consumer sectors, and the volatility of international derivative prices (espinoza and guayanlema, ) . in this context, ecuador has partially promoted the incorporation of biofuels into the energy supply (consejo nacional de planificaci on, ) (ministerio de electricidad y energía renovable, b) (presidencia del ecuador, ) . for example, since , a mixture of gasoline and anhydrous ethanol ( % v/v), has been available for trading in the local market (castro, ) . concerning biodiesel, the blends b , b , b , and b have been mentioned officially (agencia de regulaci on de hidrocarburos, ), but none have a real share in the transport sector. currently, the only energy use of vegetable oils is project "zero fossil fuels in galapagos" (programa de las naciones unidas para el desarrollo, ) (ministerio de electricidad y energía renovable, a). this initiative generates electricity through direct combustion of oil without previous transesterification. ecuador produces million boe (barrels of oil equivalent) of primary energy; it exports %, and about % is retained as feedstock for refineries (ministerio coordinador de sectores estrat egicos, ) . this production is insufficient to cover domestic demand. thus, in , about % of the local consumption of diesel, gasoline and liquefied petroleum gas was imported (c amara de comercio de quito, ) and from january to august , these imports increased . % compared to the same period of the previous year (banco central del ecuador, ) (planificaci et al., ) . consequently, the government has encouraged researchers and industrialists to design alternative fuels using economically viable and environmentally friendly feedstocks, as mentioned in the agrofuels plan (banerjee et al., ) (eduardo rosero, . the share of biomass in the energy matrix is less than %, and it is used mainly for cooking food and generating electricity (ministerio coordinador de sectores estrat egicos, ) . in second place is the production of anhydrous ethanol for the "gasolina ecopaís" project (about million liters) (petroecuador, ) . the production per inhabitant is comparable with countries of the region such as colombia (unidad de planeaci on minero energ etica, ) or uruguay (ministerio de industria energía y minería, ). however, comparison with world leaders such as brazil (energy research office, ) reveals a big gap of almost to . it is essential for ecuador to evaluate the actual energy contribution of biofuels and the degree of flexibility of their net output in relation to changes in production process and technology. eroi is a proper tool to carry out this evaluation since it considers the entire production cycle from planting until it is ready for blending (murphy and hall, ) . first, the study developed an extensive survey of the different raw materials with energetic potential (instituto nacional de preinversi on, ), namely agricultural and forestry crops with higher production records and yields, such as sugar cane, corn, wood, african palm (figueroa de la vega, ) , and pinion (instituto interamericano de cooperaci on para la agricultura, ). for livestock, the analysis included resources such as cattle, pigs, goats, and sheep, and focused on their transesterifiable fat content. then we determined the energy expenditure index (murphy et al., ) using the life cycle analysis (lca). this method permitted us to break down existing biodiesel and bioethanol production processes (tomi and schneider, ) . the analysis included the collection and statistical treatment of secondary information about industrial plants in operation in ecuador and other countries. the third part consisted of determining the lower calorific value and an elemental analysis by applying standardized methods for quantifying energy availability. finally, the relationship between the amount of energy produced and consumed was estimated using the eroi concept (jessica gail . few studies encompass the energy return of biofuels from different origins at the same time. furthermore, we included agricultural products with few records in the literature, such as animal fat, pinion oil, and forest residues. the objective was to group the most compelling possibilities and present their energy advantages in terms of eroi. this information is essential for allocating resources to programs that have the best energetic benefits. the presence of economic externalities does not influence eroi; instead, it relies on the concept that humans use the best resources first (hall, ) . the research includes biofuels that are being or could be used in ecuador, based on the characteristics of local industry. it incorporates the data treatment of the agricultural product to be analyzed, such as cultivation, consumption, import, and export, as well as the different levels of raw material allocation for biofuel production. the results permit us to see in a glance the effectiveness of policies implemented to meet energy requirements, given that sectors with more significant demands should be addressed first with higher eroi biofuels. this method is easy to replicate and allows the particularities of each country to be considered. the successful implementation of a biofuel program depends on technology, economics, environmental sustainability, and public policy support (saravanan et al., ) . governments of the region regulate their specifications by enacting minimum levels of ethanol or biodiesel content in blends (v azquez et al., ) (see table ). the prospects of biofuels depend on the behavior of international energy markets (pro ecuador, ) (energy information administration, ). for instance, the fall in the oil prices in (usd per barrel) would result in a severe decrease in the demand for biofuels, and lead to the collapse of their global price in the mid-term (getachew nigatu, kim hjort, agapi somwaru, ) . environmental standards, energy security, rural economic activation, and climate change will drive bioethanol consumption in the u.s. and the e.u., which, together with brazil, would remain as the leading producers worldwide (getachew nigatu, kim hjort, agapi somwaru, ) . their production would increase from billion liters in to about billion liters by . additionally, emerging economies like china, thailand, and india would contribute up to billion liters of ethanol by (u.s. department of energy, ). global expansion of biodiesel is expected to increase from to billion liters between and (union zur f€ orderung von oel -und proteinpflanzen e.v., ). again, the e.u., u.s., and brazil would dominate the market with good participation by argentina in south america. this production will utilize % of the world's vegetable oil (pro ecuador, ). ecuador began producing biodiesel from african palm in , and up to , all production was for export. in , when national production reached million liters, the government enacted executive decree establishing b blending for biodiesel. this proportion was supposed to increase gradually to b , which would mean achieving a production of million liters of biodiesel per year. for anhydrous ethanol, production started in with ecopaís gasoline, which was to contain up to % anhydrous bioethanol. the national fuel trade agency (arch) states that only ecopaís gasoline ( % v/v) is available in the current market, and biodiesel will have to wait for distribution and marketing policies (hernan, ) . the use of vegetable oil is limited to pilot projects such as zero fossil fuels for galapagos and the juan jos e castell o zambrano foundation, in cooperation with termopichincha; they have been burning pinion oil without transesterification to generate electricity since . agricultural zoning published by the ministry of agriculture (mag) identified the provinces with highest potential for the production of sugar cane (guayas %, loja %, cañar %, imbabura % los ríos % and carchi < %) and african palm (esmeraldas %, los ríos %, sucumbíos %, pichincha %, santo domingo de los ts achilas %, orellana %, and guayas %) (instituto nacional de preinversi on, ). this information is essential for evaluating the energy required to transport biofuels to blending centers (enclosed in thick lines on the maps). figure shows the geographical distribution of the energy potential of sugar cane on the left ( tj) and african palm on the right ( tj) (instituto ecuatoriano de estadística y censos, ). this record includes fermentation, transesterification, direct combustion, gasification, and pyrolysis. although the potentials do not include energy return, the advantage of african palm is clear in terms of available energy. the eroi calculated in this research includes the energy associated with refining and transporting fuel to the country's main point of distribution where blending would take place. the ratio of this amount of energy to the energy obtained when burning the fuel is called the energy return on investment -point of use (eroi pou ) (j. lambert, hall, balogh, poisson and gupta, ) . 〖eroi〗 pou ¼ ðenergy returned to societyÞ ðenergy used to get and deliver that energyÞ ( ) eq. ( ) described by ). the eroi is a useful decision-making tool before exploiting an energy resource or when defining public policy. for example, a value of or : means that society would benefit from this energy resource by %, and the remaining % is necessary to obtain that energy. this proportion varies considerably depending on the source. for example, gas and oil can have an eroi of : , but in the case of tar sands, the eroi decreases to : . the value for coal is usually higher and can be up to : . among the most compelling renewable energies, the eroi is : for hydroelectric generation and : for wind power (j. lambert et al., ) . for the specific case of biofuels, the values are less encouraging; for example, ethanol from corn has erois that range from . to . in u.s. distilleries (murphy and hall, ) . the source is not the only factor that determines the eroi; other inputs such as technological improvements or depletion can play crucial roles. gagnon et al. addressed this topic for oil and gas production worldwide. the eroi increased from : in to about : in , and then it decreased again to : in (gagnon et al., ). here it is clear that during the first period from to , the energy return increased thanks to technological advances and extraction methods; however, during the second period from to , depletion of the sources exceeded the benefits achieved through technological advances. charles hall (the originator of the concept of eroi) states that to keep our civilization working in the way we know it, energy systems should have erois higher than ). the eroi can vary depending on the system components; for example, boundaries and outputs/inputs assumed in the energy balance, and local particularities such as production methods, types of raw materials, and energy consumed for environmental remediation (see figure ). lca starts as a horizontal analysis tool and examines the inputs and outputs of every component of the process. then it carries out a vertical analysis of the activities of each stage (petraru and gavrilescu, ) , while seeking not to include irreversibilities that are not useful to society (arvesen and hertwich, ) . in general terms, this tool includes the definition of objectives, scope, inventory analysis, impact assessment, and interpretation of results. in ecuador, ethanol comes from sugar cane only; therefore, energy consumption data are from actual industrial plants. in contrast, there is no industrial production of biofuels based on corn, wood, fat, or african palm. hence, statistical tools and case studies are needed to determine the relationship between the energy consumption "dependent variable" and the raw material "independent variable." for biofuels production, this information allows the construction of four scenarios with different levels of corn, wood, fat, and african palm designated. this approach is based on the concept of economy of scale, where the unitary production cost decreases as the scale of operation increases. all investigations that seek to determine the eroi of any resource use one of the following three techniques: process analysis, economic inputoutput, or a hybrid of both (murphy et al., ) . looking for the implications of energy return in society (jessica gail , reviewed the eroi of different sources. the most relevant references are presented below with a description of the technique used in each case (see table ). the technique employed in each case defines the methodology and the instrument used to identify and account for energy flows. it consists of two dimensions. the first describes the boundaries of the production chain from cultivation to distribution; these are the energy outputs. the second sorts by levels and indicates the type of energy and materials directly or indirectly associated with the process. in this case, we chose level , which includes the energy inputs under investigation and the inputs from the other energy sectors (murphy et al., ) . this ensemble of dimensions results in a technique based on process analysis. the lca is the instrument that identifies the processes within the boundaries defined in dimension one, as well as the energy flows of dimension two. the aim is to define a roadmap for selecting the proper energy balance and the type of data to be collected. the scenarios vary the proportions of feedstock to estimate energy consumption through linear regression models. the variance analysis of the models and the t-test for the slopes show a statistically significant relationship between the amount of raw material destined for biofuel and energy consumption, since the p-value of each test is less than the level of significance chosen (α ¼ . ). moreover, this relationship demonstrates a high correlation between the variables according to the values of r (see tables , ; figure ). the selection criteria rely on the scenario that results in less energy consumption during the feedstock's industrial stage. the following are the best scenarios for each case. corn. -s ( %) with energy consumption in the industrial stage equal to . mj/kg bioethanol, which is higher than industrial plants in argentina . mj/kg, u.s. . mj/ kg, and chile . mj/kg. wood. -s with energy consumption of . mj/kg of bioethanol, a level comparable to other industrial plants, . mj/kg in the united kingdom, . mj/kg in canada, and . mj/kg in brazil. african palm. -s ( . mj/kg biodiesel), which represents . % of total energy consumption. it is within the range of preliminary studies . - . mj/kg biodiesel. animal fat. -s ( . mj/kg), which represents . % of total energy consumption; this is slightly higher than the values presented in preliminary studies ( . - . mj/kg). pinion. -s ( . mj/kg biodiesel), which represents . % of total energy consumption; this is higher than values presented in peru . mj/kg, argentina . mj/kg, and india . mj/kg. (murphy et al., ) and (jessica gail lambert et al., ) . reference technique ethanol and biodiesel production (pimentel and patzek, ) process analysis oil and gas discovery and production (guilford, hall, o'connor and cleveland, ) process analysis oil and gas production (guilford et al., ) hybrid oil gas and tar sand production process analysis oil and gas production (hu et al., ) economic input-output the production of biofuels generally involves the generation of some co-products; for example, glycerin in biodiesel, which accounts for approximately % of energy consumption. likewise, bioethanol from corn has multiple co-products that include oils and meal for animal feed; their exclusion or incorporation into the analysis produces essential changes in the final values of the eroi. hall et al. ( ) addressed this issue when comparing the eroi of corn alcohol, previously obtained by (kim and dale, ) and (pimentel and patzek, ) , as . : and . : , respectively. approximately % of this difference is due to the treatment and use of the co-products generated in the industrial process. this work excluded the subsequent treatment of co-products because of uncertainty about the allocation of the weighting factors of their energy consumption and their final use . hence, the scenarios developed in this work are conservative in this sense. similarly, we excluded the energy required for environmental remediations because it could change according to the specific obligations in each zone. finally, esmeraldas refinery was used as the final destination of biofuels, since this is where the mixing of ecopaís b gasoline take place. considering these methodological aspects, the calculated eroi is very close to the eroi at the point of use, with less than % difference ) ( % in our cases). we determined the energetic availability from the net amount of heat produced by fuel combustion under controlled conditions (cengel, yunus. boles, ) . local producers and research centers provided the samples. they are listed below with the respective selection criteria (see table ). finally, we obtained the net calorific value (ncv) from specialized tests, such as astm d - and (sader and oliveira, ) , for gross calorific value and elemental analysis, respectively. table . energy consumption involves the entire production chain, including the stages of cultivation, distribution, chemical transformation, and delivery to blending facilities. figures and show the extraction of biofuels from agricultural commodities and animal fat, respectively. the following is a model for calculating the eroi at the point of use for sugar cane in scenario . other raw materials follow the same procedure. the desegregation of formula ( ) shows the decrease in eroi through the production chain. this information is also shown as a percentage, taking the cultivation stage as a reference. eroi farming ¼ : : the eroi farming represents the energy return of sugar cane, considering cultivation only. after adding the other stages, the eroi becomes . , . , and . for transportation, transformation, and distribution (see figure ). the eroi farming begins at . and decreases by . %, . %, and . % by the end of its production chain. that is, . x ( - . )% ¼ . . this detail allows the analysis of consumption by subprocess. for example, the eroi of forest residues decreases by . % by the final stage. as a result, we obtain an eroi at the point of use that is less than one. the ncv of sugar cane, african palm, fat, and pinion was obtained experimentally, and ncv of corn and wood was theoretical. the following eight figures compare the results of the energy consumed per stage and the available ncv, to observe net benefits. the results confirm that energy consumption is strongly influenced by both the raw material and the industrial stage. in general terms, biodiesel has an advantage over ethanol (see table ). the calculation of the eroi has been adjusted not only for the agricultural and industrial reality of ecuador, such as ethanol from sugarcane, but also for raw materials, whose production is part of national development plans and public policies for future projects such as biodiesel. therefore, we propose substitutive goods to generate more inputs that will allow the prediction of the net energy impact of introducing biofuels from different origins under current production conditions. besides eroi, other socioeconomic considerations can arise, such as the creation of jobs and the activation of the agricultural sector, as well as reducing refined fuel imports resulting from the lack of internal production capacity. the fossil fuel subsidy policy impacts the national government in two ways. on one hand, subsidized fuel increases consumption due to its low price, and the country has to allocate around usd billion per year ( % of gdp) to meet the demand. on the other hand, since it does not have refining capacity to cover the domestic market, the government has to import derivatives at fluctuating prices, placing the local dollarized economy at risk year after year. the issue gained importance in the country after october , because the ecuadorean government attempted to eliminate gasoline and diesel subsidies. the measure provoked intense social protests from several sectors, such as transport, agriculture, and industry. finally, in the face of excessive pressure, it had to withdraw the decision. therefore, all options that are considered should adopt an integrated analysis that includes technical, economic, and social aspects. the eroi could provide vital information to address this issue from a more insightful standpoint. development is strongly related to the eroi on which societies base their economies. in ecuador, the production of primary energy from fossil fuels is close to %, and biofuels constitute less than %. however, increasing this share is a subject of constant debate and pressure from various sectors. this is where the concept of eroi plays an influential role, since it allows real-net contributions to be compared with the apparent benefits of green energy, driven mainly by actions to mitigate climate change. in many cases, those actions ignore the fact that fossil fuels provide energy for developing renewable technology. the eroi values for ecuador range from . to . for ethanol and . to . for biodiesel. moreover, the results show that the greatest energy demand is for cultivation ( . - . %) and industrial stages ( . - . %), so we compared them with regional and world values. biodiesel from african palm la fabril commercially, oils and fats are one of the most concentrated sectors in ecuador according to the center for economic and social rights. la fabril is one of eight companies that account for % of the national market. since , it has exported oil for biodiesel using the following method, astm d /b (blends with diesel) (lasso, ) . there is no industrialized refining of fat to biodiesel yet. therefore, the department of petroleum, environment, and contamination (dpec) provided a sample that complies with technical regulations in terms of calorific value. the producer is part of the dpec customer portfolio. biodiesel from pinion iner pinion oil, as an energy resource, is a pilot program of the ministry of energy and non-renewable natural resources, and iner is the implementing branch of the project (instituto interamericano de cooperaci on para la agricultura, ). the calculation for the other raw materials is available at https://uceedumy.sharepoint.com/personal/wgchiriboga_uce_edu_ec/_layouts/ /doc.aspx? energy consumption for growing sugar cane is . mj/kg, which on the average is . % more energy than brazil, but . % less than the u.s. the situation is different for corn, which in ecuador requires . mj/kg, compared to . ; . ; and . mj/kg in the u.s., chile, and argentina, respectively. for african palm, energy consumption is . mj/kg, . % higher than indonesia and . % higher than figure . from a to g, breakdown of the energy consumed to produce biofuel (left), and the total energy released by combustion (right) according to the feedstock and assumed scenarios. h is a summary of the eroipou for all the feedstocks considered and sorted by scenarios. the advantage of biodiesel is evident. colombia. for livestock, ecuador consumes about % more energy than mexico and brazil, and up to . % more than the u.s. energy consumption in pig raising is significantly lower due to space management and the type of feeding, so the energy demand comes from the transesterification of fat. this investigation reports the current situation of energy management for both alcohol fermentation and dehydration and the transesterification of fat. we also considered the pretreatment and refining stages of each raw material. in ecuador, the incorporation of biofuels into the energy matrix has two main objectives. on one hand, it seeks to reduce the environmental impact of greenhouse gas emissions by using biomass, whose carbon comes from photosynthesis. on the other hand, it seeks to displace imports of petroleum-derived fuels, mainly gasoline and diesel, while encouraging national agricultural production. in this context, ethanol from sugar cane has the most favorable eroi, at . , which leads to the following analysis. if the aim were to meet nationwide demand with ecopaís, the energy market for anhydrous ethanol would be , kboe ( , , mj). this amount of energy would require , , l of alcohol (energy intensity ¼ . mj per liter) and km of arable land (instituto interamericano de cooperaci on para la agricultura., ). fossil fuels could provide % of this energy; however, there would still be a contribution by renewables of about , , mj. for the other raw materials analyzed, there would not be a net energy contribution by ethanol. in the case of wood, there would be a negative energy balance since its eroi is between . and . . for biodiesel, we chose african palm to carry out a similar analysis, and the eroi calculated was . . the production of b blends to meet nationwide demand would represent , kboe or , , mj, and would involve around , , l of biodiesel and , km of land (energy intensity ¼ . mj per liter). pinion is worth highlighting because its eroi is . , and it constitutes an excellent opportunity because it does not compete directly with the food sector. only living fences are required to produce it, so it would therefore not jeopardize land use to a significant extent. biodiesel from animal fat (cattle . : and pigs . : ) appears to be more feasible than ethanol, as shown in figure h . the best production scenarios for both ethanol (sugar cane . ) and biodiesel (african palm . ) suggest that expending a unit of energy to produce biodiesel would return . more energetic units than bioethanol. besides, data from the last national energy balance showed that the demand for diesel is greater than gasoline ( , kboe and , kboe, respectively) due to the high energy consumption characteristics of this subsector, and the ease of fuel utilization for industrial activities. finally, it is worthwhile analyzing how ecuadorians use fuels for transportation. for example, individual or light cars consume % of the gasoline, and in the best case would transport five users at a time. and collective or heavy-duty transport utilizes the remaining %. in contrast, light and individual transport consumes % of the diesel and collective or heavy-duty transport utilizes up to %. so, since the biodiesel market would mean a higher energy return, better land use, and greater coverage of benefited users, it should be analyzed why, so far, ecuadoreans still cannot trade biodiesel locally. the study presents an initial analysis of the energy return of the biofuels considered in national development plans for transport. the energy return rate of bioethanol is feasible only for sugarcane because it has an energy surplus of . . for biodiesel, the values are favorable in all the selected scenarios, since its eroipou was always greater than . the stages of cultivation and industrial transformation are the most energy-demanding; therefore, energy efficiency policies should begin by addressing these stages, so that we can achieve world productive yields like those of brazil and the u.s. the market for bioethanol as fuel is million dollars ( million liters). petroecuador e.p. has awarded the administration of the project to three private companies and a % share to small farmers. this gasoline is available in of the provinces of the country. in , it achieved first place in sales with % of the total market. the numbers are encouraging but the energy ministry has questioned the project since , because it is cheaper to import ethanol from neighboring countries. the reasons are the lack of local production of agricultural inputs and the high cost of labor. based on this analysis, the project seems to be maintained solely by the , direct jobs it generates. however, even if the objective is to prioritize job stability, the eroi could provide public policymakers with adequate information on each stage in order to correctly direct incentive programs. the biofuels program was launched in april , and included biodiesel as a priority. that year, the organic law of energy efficiency called for the creation of the necessary policies for promoting the marketing of biofuels at the national level. as of the writing of this document, there are no clear implementation programs or plans for biodiesel. in the context of energy efficiency and renewable energy, the public policy proposes the electrification of the transport matrix. by , new units incorporated into public transport must only be electrically powered. this measure covers % of national diesel demand, but the actions to be taken for light and heavy units, which constitute %, are not clearly expressed. here, encouraging eroi results provide an alternative in the medium term, mainly because biodiesel blends do not incur the drawbacks of electrical units, such as battery life, limited range, dispatchability, and recharging points. the land required to meet domestic demand with ecopaís and biodiesel (b ) shows similar energy densities, since both have yields of about . mj per km . that is, the same amount of land would be committed to generating a unit of energy from sugar cane or african palm. however, this issue deserves further study that considers the water required and the net greenhouse gas emissions generated. we analyzed biofuels for use in transportation engines, which implies high-quality fuels and consequently, high energy demands during refining processes. diversifying the matrix and allocating fuels for direct combustion should be considered, such as pinion, for direct use in power generation. here, the eroipou would increase from . to . . the unprecedented crisis in the oil markets due to the covid- outbreak has caused severe impacts on oil-exporting economies, such as that of ecuador. in this regard, some analysts suggest that prices will rise considerably in the medium term, which would imply a new increase in the cost of derivatives. currently, ecuador's social environment makes it highly unlikely that subsidies will be withdrawn. this forces the ecuadorian government to generate guidelines focused on incorporating viable options for the diversification of the energy matrix to alleviate the fiscal deficit caused by the subsidy. in the current situation of low global energy demand, ecuador should use the opportunity to generate public policies aimed at defining how, when and what quantity of derivatives to acquire in the future, as well as the amount of raw materials to be dedicated to the production of biofuels. both decisions must consider, among other things, the eroi as a technical criterion to indicate which biofuel to produce to minimize the impact on other energy resources and economic sectors. norma para el manejo y control del biodiesel. quito: registro oficial del ecuador integrating agronomic factors into energy efficiency assessment of agro-bioenergy production -a case study of ethanol and biogas production from maize feedstock more caution is needed when using life cycle assessment to determine energy return on investment (eroi) standard specification for diesel fuel oil, biodiesel blend (b to b ) reporte del sector petrolero global scenario of biofuel production : past , present and future dynamic energy return on energy investment ( eroi ) and material requirements in scenarios of global transition to reflexiones en torno al desarrollo de los biocombustibles en ecuador. ceda, . centro ecuatoriano de desarrollo ambiental -temas de an alisis termodin amica plan nacional de desarrollo. plan nacional de desarrollo. quito: consejo nacional de planificaci on embodied energy and energy return on investment analyses in maize production for grain and ethanol under center pivot, subsurface drip, and surface (furrow) irrigation with disk tillage and no-till practices energías renovables observatorio de energías renovables en am erica latina y el caribe agrocombustibles dar an impulso a palma y caña energy information administration governo federal, rio de janeiro ep petroecuador firma contrato con empresas alcoholeras para la producci on de ecopaís balance y proyecciones del sistema de subsidios energ eticos en ecuador. an alisis, quito tablero comando para la promoci on de los biocombustibles en ecuador a preliminary investigation of energy return on energy investment for global oil and gas production projecting the effect of oil price regimes on biofuel markets a new long term assessment of energy return on investment (eroi) for u.s. oil and gas discovery and production will eroi be the primary determinant of our economic future? the view of the natural scientist versus the economist what is the minimum eroi that a sustainable society must have? energies seeking to understand the reasons for different energy return on investment (eroi) estimates for biofuels an alisis del uso de biocombustibles en ecuador periodo a mini review on renewable sources for biofuel energy return on investment (eroi) of china's conventional fossil fuels: historical and future trends encuesta de superficie y producci on agropecuaria continua. inec atlas de la agroenergía y los biocombustibles en las am ericas atlas bioenerg etico del ecuador life cycle assessment of various cropping systems utilized for producing biofuels : bioethanol and biodiesel eroi of global energy resources. preliminary status and trends. college of environmental science and forestry energy, eroi and quality of life large quantities of high quality energy eroi of different fuels and the implications for society la palma aceitera en el ecuador: ¿un cultivo social y sustentable? línea de fuego balance energ etico nacional plan maestro de electrictidad plan nacional de eficiencia energ etica - . plan nacional de eficiencia energ etica ecuador marca su rumbo en la industria de los agrocombustibles comments on energy return on investment ( eroi ): reconciling boundary and methodological issues year in review-eroi or energy return on (energy) invested order from chaos : a preliminary protocol for determining the recent developments and key barriers to advanced biofuels: a short review towards an improved methodology for energy return on investment (eroi) for electricity supply pollution prevention, a key to economic and environmental sustainability informe ethanol production using corn, switchgrass, and wood informe estadístico enero agosto time series eroi for canadian oil and gas dectreto ejecutivo . registro oficial del ecuador . viceministerio de promoci on de exportaciones e inversiones energía verde para gal apagos breve reseña hist orica de la exploraci on petrolera de la cuenca oriente quantification of total nitrogen according to the dumas method biofuel policy in india: a review of policy barriers in sustainable marketing of biofuel issues to consider , existing tools and constraints in biofuels sustainability assessments issues to consider , existing tools and constraints in biofuels sustainability assessments municipal solid waste system analysis through energy consumption and return approach alternative fuels data center balance energ etico nacional colombiano union zur f€ orderung von oel sustainable development goals documento de trabajo no. , gerencia de políticas y an alisis econ omico. osinergmin, lima we acknowledge the contributions of iner, dpec, and la fabril in providing biodiesel samples and soderal s.a., for permitting us to collect information on the energy consumption of its industrial processes. the authors declare no conflict of interest. no additional information is available for this paper. key: cord- - xrq cg authors: barrington, debbie s.; james, sherman a.; williams, david r. title: socioeconomic correlates of obesity in african-american and caribbean-black men and women date: - - journal: j racial ethn health disparities doi: . /s - - - sha: doc_id: cord_uid: xrq cg the high prevalence of obesity among black americans warrants additional investigation into its relationship with socioeconomic position (sep), sex, and ethnicity. this cross-sectional study utilizes – data from the national survey of american life, a nationally representative sample of african-americans and caribbean-blacks aged years and older. multivariate logistic regression models stratified by ethnicity and sex describe the independent associations between obesity and multilevel socioeconomic factors after adjustment for age, other sep measures at the individual, family and neighborhood levels, and health behaviors such as physical activity, alcohol intake, and smoking. a positive relationship was observed between obesity and family income among african-american and caribbean-black men. receipt of public assistance was a strongly associated factor for obesity in caribbean-black men and women. among african-american women, inverse relationships were observed between obesity and education, occupation, and family income; residence within a neighborhood with a supermarket also decreased their odds of obesity. residence in a neighborhood with a park decreased the odds of obesity only among african-american men, whereas residence in a neighborhood with a supermarket decreased the odds of obesity among caribbean-black men. the social patterning of obesity by individual, household, and neighborhood socioeconomic resources differs for african-american and caribbean-black men and women within these cross-sectional analyses; an appreciation of these differences may be a prerequisite for developing effective weight control interventions and policies for these two populations. the high prevalence of obesity among non-hispanic black americans ( . %), aged years and older in , as compared with . % for the general us population, remains an important public health problem [ ] . obesity has a broad range of health consequences, and its higher prevalence among non-hispanic blacks puts them at increased risk for type diabetes (blacks = . %, whites = . %), coronary heart disease (black women = . %, white women = . %), asthma (blacks = . %, whites = . %), and stroke (blacks = . %, whites = . %) [ ] . the important role of socioeconomic position (sep) in the obesity epidemic has long been a focus of research [ ] [ ] [ ] [ ] . sep is defined as one's location in the societal structure that determines differential access to power, privilege, and desirable resources [ ] . it is a multidimensional concept that can be measured at ( ) the individual level, e.g., education, earnings, and occupation; ( ) the household level, characterized by familial resources, e.g., poverty, family income, and wealth; and ( ) the neighborhood level, described by aspects of living conditions not captured by individual or household level variables, e.g., community structural characteristics, neighborhood poverty, and crime [ , ] . prior research has documented correlations between lower rates of obesity and residence in communities with beneficial structural characteristics of neighborhood sep, including the presence of neighborhood parks and supermarkets [ ] [ ] [ ] . research findings on the relationship between obesity and individual and household measures of sep, however, have been more mixed. for example, some studies have revealed a weakening of the protective effect of increasing education on obesity over the past years, a consequence of the increase in obesity among the most educated [ ] . the inverse association between sep and body mass index (bmi) and obesity is stronger among women compared with men [ , [ ] [ ] [ ] [ ] [ ] . some studies, in fact, reported a reversal of the expected inverse sep-obesity association among men; i.e., men of high sep were more likely to have increased bmi and be overweight or obese than men of low sep [ ] [ ] [ ] ] . furthermore, nativity status (foreign-born vs. us-born) differentials in the association of an individual-level measure of sep on obesity have been reported among black americans, with native-born blacks being at higher risk [ ] . few studies, however, have examined sex-specific associations between obesity and multilevel measures of sep within an ethnically diverse group of black americans. hence, the present study investigates the potential differential associations between obesity and individual, household, and neighborhood-level sep indicators among black american men and women (african-americans) and blacks with caribbean ethnicity (caribbean-blacks). elucidation of the differential patterning of multidimensional measures of sep on obesity among african-american and caribbean-black men and women would be beneficial for developing effective interventions to reduce obesity and obesity-related diseases within an increasingly heterogeneous us black population. this cross-sectional study utilizes data from the national survey of american life (nsal). the nsal is part of the national institute of mental health (nimh) collaborative psychiatric epidemiology surveys (cpes) initiative that also includes the national co-morbidity survey replication (ncs-r) and the national latino and asian american study (nlaas) [ ] . nsal was conducted according to the guiding principles in the declaration of helsinki. all procedures involving human subjects, including oral and written consent from all participants years of age and older, were approved by the institutional review board at the university of michigan [ ] . the nsal includes a sample of non-hispanic whites, african-americans, persons who identified as black but did not have ancestral ties to the caribbean (including foreign-born blacks), and caribbean-blacks, persons who identified as black and who either were born in caribbean area countries ( % of the caribbean-black sample), had parents or grandparents who were born in the caribbean, or had indicated that they were of caribbean ethnicity. the nsal survey data includes assessments of mental, emotional, and physical health and residential, environmental, and socioeconomic characteristics. data were collected between february and june with response rates of . % for african-americans, . % for caribbean-blacks, and . % for whites. this paper capitalizes on the growing heterogeneity of the us black population as reflected in the nsal sample and reports findings for african-american and caribbean-black men and women, aged years and older within the nsal sample. the study outcome is obesity, characterized as having a body mass index (bmi, weight (kg)/height (m) ) or higher [ ] . bmi is calculated within the nsal based on selfreported weight and height. the independent variables include self-reported measures of adult sep at the individual, family, and neighborhood levels. sep indicators at the individual level include current education specified as < high school (hs), hs and > hs, and respondent's main occupation categorized into professional/managerial, sales/administrative, skilled blue collar, unskilled blue collar, and service. sep measures at the family level consist of ( ) a measure of wealth or "house value," specified as at or below the median, above the median, or "none," ( ) quartiles of family income, and ( ) "public support" described as currently receiving any public assistance for the family, and dichotomized into "any" or "none." finally, sep measures assessed at the neighborhood level include self-reported measures previously found to be associated with obesity within african-americans and caribbean-blacks-having a supermarket within one's neighborhood (yes vs. no) and having a park within one's neighborhood (yes vs. no) [ ] . covariates utilized for statistical adjustment due to their known associations with sep and obesity include demographic variables such as age [ ] , categorized into less than or equal to years, - years, - years, and or more years; marital status, [ ] characterized as ( ) married or living with a partner, ( ) separated, divorced or widowed, and ( ) never married; and three measures of health behaviors, ( ) physical activity [ ] , a continuous measure based on how often the study participants worked in the garden or yard, engaged in active sports or exercise, and walked, ( ) smoking status [ ] , specified as the participant never having smoked more than cigarettes in his/her lifetime or "never smoker," having smoked more than cigarettes in the past or "past smoker," and "current smoker," and ( ) current alcohol consumption [ ] , categorized for analytical purposes into consuming no alcoholic drinks within the past year or "none," having consumed less than drinks within the past year, or "infrequent drinker," and moderate-to-heavy drinkers having consumed or more drinks within the past year or "regular drinker." to minimize bias due to differentially distributed missing data on measures of sep and bmi by ethnicity (african-american and caribbean-black) and sex, multiple imputation was performed prior to statistical analysis within the statistical software package iveware [ ] . iveware uses a sequential regression imputation method to impute values for each individual, conditional on all other values observed for that individual, consequently producing complete datasets for unbiased analyses [ ] . descriptive statistics stratified by ethnicity and by sex were then calculated. chi-square tests were performed to examine group differences in categorical variables, whereas the global f test within an unadjusted linear regression model was utilized to calculate ethnicity and sex differences in physical activity. since previous studies reveal differential sep patterning of obesity by both sex and ethnicity [ , ] , three-way interactions between measures of sep, ethnicity, and sex were tested. statistically significant three-way interactions were found for five out of the eight sep indicators, p values ranging from . to . . therefore, all nested multivariate logistic regression models assessing the strength of the independent associations between multilevel measures of sep and obesity after covariate adjustment are presented stratified by ethnicity and sex. specifically, the following five models were fitted for each sep indicator: ( ) odds ratios (ors) adjusted for age; ( ) ors additionally adjusted for individual-level sep, i.e., education, occupation, as well as for marital status; ( ) ors additionally adjusted for family-level sep, i.e., public support, house value, and family income; ( ) ors additionally adjusted for neighborhood-level sep, i.e., neighborhood supermarket and neighborhood park; and ( ) ors additionally adjusted for health behaviors, i.e., physical activity, alcohol intake, and smoking. data management was conducted using sas version , [ ] and all statistical analyses were performed using sudaan [ ] to account for the multiple imputation and the complex sample design of the nsal in calculating unbiased effect estimates and standard errors. sample sizes presented within tables are un-weighted; however, all other estimates, means proportions, and standard errors, as well as ors and % confidence intervals (cis), are weighted. table describes the general characteristics of african-american and caribbean-black men and women in the nsal sample. african-american women had the highest prevalence of obesity at . % followed by caribbean-black women at . % and african-american men at . %. caribbean-black men had the lowest prevalence of obesity at . %. caribbean-black men and women were also younger than african-american men and women with . % and . % of caribbean-black men and women being under the age of as compared with . % and . % of african-american men and women, respectively. caribbean-black men and women had greater educational attainment than african-american men and women, with . % of caribbean-black men and . % of caribbean-black women and . % of african-american men and . % of african-american women having > hs education. men were more likely to be married or living with a partner than women; caribbean-black men had the highest prevalence at . %, while african-american women had the lowest at . %. in addition, men were more likely than women to be employed in the skilled and unskilled blue collar professions; unskilled blue collar employment was highest for african-american men at . %. women were more likely than men to be employed in service professions. moreover, caribbean-black men and women, at . % and . %, respectively, were more likely to work in professional/ managerial positions compared with african-american men and women at . % and . %, respectively. african-american women were the most likely to receive public support, and accordingly, most likely to have had the lowest family income compared with all other ethnic/sex groups. caribbean-black men were least likely to receive public support and to have had the highest family income. african-american men were most likely to be homeowners relative to all other ethnic/sex groups, whereas caribbean-black women were least likely to be homeowners. caribbean-black men and women were more likely than african-american men and women to live in neighborhoods that had a supermarket or a park. caribbean-black men had the highest prevalence, in that % lived in a neighborhood with a supermarket and . % resided in a neighborhood with a park. african-american women had the lowest prevalence with approximately % residing in a neighborhood that had a supermarket or park. men reported higher rates of physical activity than women, with caribbean-black men having the highest average score ( . ) and african-american women having the lowest ( . ). seventy-nine percent of caribbean-black women never smoked, whereas only . % of african-american men never smoked. finally, african-american women were least likely to consume alcohol in the past year where . % never drank. caribbean-black men were most likely to drink alcohol in the past year and . % were regular drinkers. tables , , , and present the adjusted odds ratios (ors) and % confidence intervals for the associations between obesity and individual-, family-, and neighborhood-level socioeconomic position (sep) among african-american men, caribbean-black men, african-american women, and caribbean-black women, respectively. unless otherwise stated, all ors were determined from the fully adjusted models. for african-american men, no significant associations between obesity and any individual-level measure of sep were observed ( table ) . low sep at the family level, however, was associated with a lower odds of obesity. within all adjusted models for african-american men, family income within the lowest quartile was protective against obesity relative to the highest quartile, or = . , % ci ( . , . ). furthermore, african-american male homeowners with housing equity at or below the median had a % increased odds of obesity compared with their non-home-owning counterparts, or = . , % ci ( . , . ). neighborhood-level sep was also associated with obesity, with all adjusted models showing lower odds of obesity for african-american men residing in neighborhoods that contained a park compared with those who lived in neighborhoods without one (or = . , % ci ( . , . )). as shown in table , none of the individual-level measures of sep for caribbean-black men was significantly associated with obesity, paralleling the findings for african-american men. nevertheless, selected family-and neighborhood-level sep measures were associated with obesity. for example, like african-american men, low family income was protective for caribbean-black men within the age-adjusted model; however, this association became non-significant (p > . ) with additional covariate adjustment. furthermore, caribbean-black men who received any public assistance had . times the odds ( % ci . , . ) of obesity compared with their counterparts who did not. finally, caribbean-black men residing in a neighborhood containing a supermarket experienced an % decreased odds of obesity compared with those in neighborhoods without this amenity, or = . , % ci ( . , . ). in contrast to men, table shows statistically significant associations between measures of individual-level sep and obesity for african-american women. african-american women with < hs education had . times the odds ( % ci ( . , . )) of obesity than those with > hs education. though only borderline significant in fully adjusted models, african-american women with a hs education had . times the odds ( % ci ( . , . )) of obesity compared with those with > hs education. african-american women employed in the sales/administrative occupations had % lower odds of obesity compared with african-american women employed in service employment, or = . , % ci ( . , . ). in contrast to african-american men, higher family sep was protective against obesity for african-american women. though of borderline significance, african-american women who received public support had a % greater odds of obesity compared with those not receiving such support, or = . , % ci ( . , . ). though not statistically significant, african-american women with family income in the third quartile were associated with a % increased odds of obesity compared with women in the highest quartile, or = . , % ci ( . , . ). african-american females with housing table summarizes associations between sep and obesity among caribbean-black women. occupation is the only individual-level sep measure that was associated with obesity in this group. being employed within professional/managerial occupations was associated with a decreased odds of obesity compared with employment in service occupations, after adjusting for age, marital status, and other individual-level, family-level, and neighborhood-level sep measures, or = . , % ci ( . , . ). this association became statistically insignificant, however, after adjusting for physical activity, smoking, and alcohol consumption, or = . , % ci ( . , . ). similar to african-american women, receipt of public assistance increased the odds of obesity for caribbean-black women; however, the magnitude of the association was stronger for the latter. caribbean-black women receiving public support had . times the odds of obesity compared with caribbean-black women not on public assistance, % ci ( . , . ). yet, unlike african-american women, in ageadjusted and individual-level sep adjusted models, caribbean-black women with family income in the third quartile had a decreased odds of obesity compared with those with family income in the fourth quartile. in fully adjusted models, this relationship became statistically insignificant, or = . , % ci ( . , . ). no association was observed between this study of the association between multiple dimensions of sep (individual, family, and neighborhood) and obesity in a sample of us blacks found that associations varied by ethnicity and by sex. among african-american men, no statistically significant associations between sep and obesity were observed at the individual level, but a positive relationship was observed for family sep; namely, african-american men in the bottom quartile of family income and who had no housing equity had the lowest odds of obesity. similar to african-american men, there was no association between adulthood sep at the individual level among caribbean-black men. for caribbean-black men, more complex sep patterns for family income were observed, wherein ( ) obesity increased among those receiving public assistance and ( ), similar to african-american men, a positive association was observed between family income and obesity. the association between public assistance and the increasing odds of obesity among caribbean-black men is consistent with a previous report showing that participation in public assistance programs increased the risk of adult obesity [ ] . in this particular study, the association was stronger among men than women and was mediated by dietary quality as assessed by higher soda consumption. moreover, in the current study, our finding of a positive association between obesity and sep at the family level among black men is also in line with previous reports [ , , , ] . african-american elementary school boys with low sep have been reported to engage in more vigorous physical activity than high sep boys through participation in team sports such as football and basketball [ ] . this engagement in vigorous team sports, if it [ ] , is a possible contributing factor in lowering the risk of obesity among low sep african-american and caribbean-black men. this is a hypothesis that should be tested in prospective research. moreover, the higher obesity rate among high sep men has been postulated to be due to the positive effect increased body weight has on higher earned income and social prestige among men [ ] . future longitudinal investigations should determine whether perceived and actual positive economic consequences for increasing body size drive the positive relationship between sep and obesity among men. for african-american women, the expected inverse relationship between individual-level sep and obesity was seen for education [ ] ; however, educational attainment was not associated with obesity among caribbean-black women. in line with previous research [ ] , our study also reveals that higher status occupations, i.e., sales and administrative jobs among african-american women and professional and managerial jobs among caribbean-black women, are associated with lower odds for obesity than lesser status service professions. finally, our results at family-level sep show that similar to caribbean-black men, receipt of public assistance increased odds for obesity among women, with a stronger association for caribbean-black women. lastly, our results show important ethnic and sex differences in the association between community sep characteristics and obesity. the lower odds of obesity among caribbean-black male and african-american female residents in neighborhoods containing a supermarket is consistent with prior research [ , ] . in addition, the lower odds of obesity for residence within a neighborhood containing a supermarket found among caribbean-black women suggests that this relationship may hold for them as well despite the lack of statistical significance most likely due to low statistical power. the absence of any relationship between obesity and residence within a neighborhood containing a supermarket among african-american men warrants further investigation. it is important to highlight the substantial decrease in the odds of obesity exclusively among african-american men who live in neighborhoods containing a park. research has shown that increased access to parks is associated with increased moderate-to-vigorous physical activity in boys but not among girls aged to years [ ] . for many black men, these childhood patterns of engaging in vigorous competitive team sports (e.g., basketball) in neighborhood parks extend into early adulthood, a pattern not seen historically among black women [ , ] . additional research is needed to determine whether elevated energy expenditure due to increased access to recreational parks across the life course explains the lower prevalence of obesity among african-american men living in neighborhoods with community parks. previous research documenting a lack of association between sep and exercise frequency in black women may explain the absence of a relationship between neighborhood parks and obesity among african-american and caribbean women within our findings [ ] . further theoretical and empirical investigations are needed to uncover additional mechanisms through which measures of sep at the neighborhood level independently operate to increase obesity within the various ethnic and sex groups. to our knowledge, this is the first study to document associations between multilevel and multidimensional measures of sep and obesity in a sample of us self-identified and caribbean self-identified black americans, while using an intersectionality approach centered on both within-race ethnic and sex differentiation. methodological strengths also include the employment of multiple imputation of missing data. this study has several limitations, however. multiple imputation was not performed on measures with over % of missing data, such as individual-level income, and so, this variable was not included within the analysis in order to minimize bias [ , ] . furthermore, the lower sample size of caribbean-blacks within the nsal dataset limited statistical power to examine any additional variation in the sep-obesity associations by nativity status, i.e., foreign-born vs. us-born. the public-use nsal questionnaire utilized for analysis included only self-reported measures of neighborhood physical characteristics and did not allow for geocoding addresses to include census tract measures, i.e., percentages of families below the poverty, unemployed and/or low-educated adults, and homeowners within a neighborhood, for multilevel modeling. although the inability to examine objective assessments of neighborhood sep within hierarchical models is a disadvantage, perceived measures of neighborhood resources have been found in previous studies to be equally robust correlates of obesity as observed neighborhood indicators [ ] . the cross-sectional nature of the nsal study design does not establish a clear, unbiased temporal relationship between multilevel sep indicators and adult obesity; therefore, neither causality nor direction of the sep-obesity associations can be ascertained with certainty. the nsal, one of the few studies that allow for an examination of the socioeconomic correlates of cardio-metabolic health by ethnicity and sex within black americans, was conducted in - and hence is an established dataset. notwithstanding, the stability of sep indicators over time for black americans, including median income, which was $ , in and $ , in , supports the present-day relevancy of our findings [ ] . the use of self-reported weight and height to estimate obesity prevalence is also a potential bias. studies have found that these self-reported measures are reasonably valid and reliable indicators of actual weight and height, although obese individuals tend to underestimate their weight [ ] [ ] [ ] . a dilution rather than an exaggeration of the magnitude of our associations is expected however if a systematic underreporting of weight is similar across sep categories. statistical adjustment for additional health behaviors related to obesity such as dietary quality could not be made within the analyses since this information is not assessed in the nsal. in addition, physical activity, crudely assessed within the nsal as a continuous measure of reported leisure time activity, is a less reliable measure of activity level than other methods which directly monitor the intensity of physical activity such as the use of double isotopically labeled water (d o ) methodology and measurement by a pedometer or tachometer [ ] . the extent to which the inclusion of dietary intake and a more reliable indicator of the intensity of physical activity would explain the associations between multilevel indicators of sep and obesity cannot be determined. our study findings highlight that adulthood sep at the individual, family, and neighborhood levels plays an important role in obesity in the us black population, and this varies by ethnicity and sex. the opposite sep-obesity relationships between black men and women suggest the need for further empirical investigation into the sex-specific mechanisms of obesity, particularly among low sep families where the disparity between young adult black women and men is the largest [ ] . moreover, the lower odds of obesity associated with residence in neighborhoods with a supermarket for african-american women and caribbean-black men, and with residence in neighborhoods containing a park for african-american men, suggests that continued public policy attention to increasing access to food and recreational facilities within black american communities, as was undertaken in the national "let us move!" comprehensive initiative for preventing childhood obesity [ ] , is likely to be an important endeavor. evidence from this study also suggests that the development of targeted, multilevel, cultural, and sex-specific societal interventions could be vital to not only curtailing the us obesity epidemic but to reducing racial inequities in survival from emerging infectious diseases such as covid- , for which obesity has arisen as a strong risk and prognostic factor in its severity [ ] [ ] [ ] . funding information this study was funded by the robert wood johnson health and society scholar's program and by the national institute on minority health and health disparities (grant number k md ). conflict of interest the authors declare that they have no conflicts of interest. ethical approval all procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the helsinki declaration and its later amendments or comparable ethical standards. informed consent informed consent was obtained from all individual participants included in the study. tables of summary health statistics for socioeconomic status and obesity: a review of the literature socioeconomic status and obesity socioeconomic status and obesity 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third national health and nutrition examination survey physical activity and its impact on health outcomes. paper : prevention of unhealthy weight gain and obesity by physical activity: an analysis of the evidence the female-male disparity in obesity prevalence among black american young adults: contributions of sociodemographic characteristics of the childhood family white house task force on childhood obesity report to the president. solving the problem of childhood obesity within a generation patients in a large health care system in california covid- is out of proportion in african americans obesity as a predictor for a poor prognosis of covid- : a systematic review publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations key: cord- -pk d hs authors: olu, olushayo oluseun; waya, joy luba lomole; maleghemi, sylvester; rumunu, john; ameh, david; wamala, joseph francis title: moving from rhetoric to action: how africa can use scientific evidence to halt the covid- pandemic date: - - journal: infect dis poverty doi: . /s - - - sha: doc_id: cord_uid: pk d hs the ongoing pandemic of the coronavirus disease has spread rapidly to all countries of the world. africa is particularly predisposed to an escalation of the pandemic and its negative impact given its weak economy and health systems. in addition, inadequate access to the social determinants of health such as water and sanitation and socio-cultural attributes may constrain the implementation of critical preventive measures such as hand washing and social distancing on the continent. given these facts, the continent needs to focus on targeted and high impact prevention and control strategies and interventions which could break the chain of transmission quickly. we conclude that the available body of scientific evidence on the coronavirus disease holds the key to the development of such strategies and interventions. going forward, we recommend that the african research community should scale up research to provide scientific evidence for a better characterization of the epidemiology, transmission dynamics, prevention and control of the virus on the continent. the ongoing pandemic of the coronavirus disease (covid- ) has severely impacted global health, economy and politics in different patterns in various continents. the disease which is caused by the severe acute respiratory syndrome coronavirus (sars-cov- ) was declared a public health event of international concern on th january [ ] and a pandemic on th march [ ] . as of th august , confirmed cases and deaths of the disease had been reported from all countries, areas and territories of the world [ ] . africa reported its first case in egypt on th february through an importation and by th august , all african countries had reported confirmed cases and deaths [ , ] . local community transmission has been established in most of these african countries. while africa remains one of the least affected regions, recent developments and data from within the continent and other regions particularly europe and america show that the numbers of cases and deaths can grow exponentially and overwhelm even the best of systems in a relatively short time if effective prevention and control measures are not instituted on time [ , ] . the fear, anxiety and panic induced by the rapid spread of the pandemic prompted several african countries to take drastic actions some of which are not necessarily based on scientific evidence. some countries closed their air, sea and land borders and imposed total national or partial sub-national lockdowns in a bid to prevent importation and minimize local transmission. given the weak health system in most african countries, mounting timely and robust responses to the covid- pandemic will be a big challenge hence the need to focus on targeted and high impact prevention and control interventions that could break the chain of transmission quickly. this becomes more pertinent given the african context where inadequate access to water, sanitation and the extended family system renders the implementation of critical preventive measures such as hand washing and social distancing challenging. this is further compounded by the global shortage of required human and material resources, which is more glaring in africa. due to the rapid spread and impact of the disease on human health, trade and travel, several research (mostly preliminary) have been conducted and published to characterize the virus and the dynamics of its transmission, prevention and control. while some of these publications have shown varying findings, conclusions and recommendations, many key and consistent evidences on the characteristics of the virus, its transmission, prevention and control are now emerging. this body of knowledge is critical to inform the development of timely, effective and context-specific prevention and control strategies in africa. in this article, we review the relevant scientific literatures on the covid- pandemic, and synthesize the relevant evidence that could potentially change the game in africa's fight against the disease; finally we propose strategic recommendations for prevention and control of covid- transmission in the africa continent specifically. the initial characteristics of covid- cases suggest that the disease is zoonotic [ ] . however, recent scientific evidence demonstrates that the current transmission pattern globally is from human-to-human. the virus is similar to the severe acute respiratory syndrome (sars) and middle east respiratory syndrome (mers) viruses with susceptibility and severity associated with older age group [ , ] , male gender [ , ] and underlying medical conditions such as poor immune functions, chronic diseases and surgery [ ] . with a basic reproduction rate ranging from . to . [ , ] and fatality rate from . to % [ , ] it is more transmissible but less fatal compared to sars and mers [ , ] . as is the case with most influenza viruses, the transmission of sars-cov- significantly reduces with an increase in temperature and humidity [ , ] , however, this advantage may be offset by the high transmissibility of the virus. three main routes of transmission have been identified among humans namely ingestion or inhalation of contaminated droplets released into the air when a patient sneezes, coughs or talks, contact with surfaces which have been contaminated by infected persons and the inhalation of aerosols generated during some medical procedures [ , ] . a few studies have also suggested faeco-oral transmission of the virus [ , ] . a recent study concluded that the virus remains viable and infectious in aerosols for a few hours and up to a few days on surfaces, particularly on stainless steel and plastics [ ] . while distinct signs and symptoms such as fever, dry cough, runny nose, difficulty in breathing, etc. have been associated with the disease, recent evidence suggests a high proportion of covid- cases are infectious but undocumented either because they have mild or no symptoms but yet continue to transmit the disease [ ] . this could contribute to the high transmissibility and rapid geographic spread of the virus. based on the lessons learnt from responding to the outbreak in china, prevention and control strategies have been proposed and are in use at various levels. in the absence of a vaccine, infection prevention and control measures that include measures to reduce or prevent exposure to the virus such as identification of suspected cases through syndromic screening at points of entry into countries, public places, health facilities, prevention of shedding of virus into the environment through respiratory hygiene have been recommended as prevention and control strategies in the general population [ ] . others include proper sanitation and waste management, social distancing to prevent contact with infected persons, avoidance of touching potentially contaminated surfaces, eyes, nose and mouth with contaminated hands and hand washing with soap and water or hand sanitizers which contain at least % alcohol [ ] . available evidence suggests that social distancing may have a dramatic effect on the transmission of sars-cov- and other respiratory infections, [ ] but there may be renewed virus transmission following relaxation of such measures due to the large proportion of susceptible people that would still be in the population [ ] . there is a convergent view on the important role of face masks in reducing the transmission of covid- by protecting healthy persons who come into contact with an infected individual and by preventing infected persons from shedding the droplets into the environment [ , ] . the use of face masks has also been associated with lower levels of anxiety and depression among the general population and health care workers which further supports its importance in prevention and control of the disease [ ] [ ] [ ] . at the individual case level, timely diagnosis, isolation and supportive management of confirmed cases, identification and follow-up of their contacts, prevention of nosocomial transmission through strong infection prevention and control methods and use of personal protective equipment are recommended [ ] . there is no known cure for the disease currently but several clinical trials involving various therapies are ongoing. who recommends that all laboratory confirmed cases should be isolated and managed in health facility settings but where this is not possible priority should be given to cases with the probability of poor outcomes such as those aged above years and with underlying medical conditions which put them at higher risk [ ] . recommendations for covid- strategy development specific for the africa continent putting the above scientific evidences on the characteristics and dynamics of covid- transmission, prevention and control into perspective against the backdrop of the social, cultural and economic context in africa, we deduce several lessons which could guide african countries to better prepare for and respond to the covid- pandemic on the continent. while the mostly hot and humid african weather and largely younger population may be deterrent factors for wide transmission of the disease, any advantage conferred by this is offset by the high transmissibility of the disease. this is more so given the high population density, larger families and large vulnerable populations such as refugees, internally displaced persons (idps), people living with the human immunodeficiency virus (hiv), tuberculosis (tb) and malnutrition thus emphasis in african countries should be on prevention of the spread of infection, especially to these vulnerable groups. in this regard, african countries should invest in identifying, developing and implementing tailor-made prevention strategies to protect at risk populations from infection [ ] . syndromic surveillance, laboratory testing and contact tracing at the community level given the high proportion of undocumented and asymptomatic cases of covid- , the use of syndromic surveillance for disease detection at points of entry may not be very effective [ ] . while syndromic surveillance may offer some level of reassurance to governments and the general population, the cost in terms of the human and financial resources associated with conducting it may offset its benefits. african countries should rather invest in active search for cases and their contacts at the community and household levels particularly the asymptomatic contacts and transmitters through scaling up testing of all persons who may have been exposed to the virus but remain asymptomatic. to achieve this, covid- testing strategies which prioritize massive testing of various categories of persons based on the transmission scenario should be developed. additionally, efforts should be made to increase testing capacity and timeliness by decentralizing testing to the sub-national levels. the evidence that the virus survives much longer on surfaces such as stainless steel and plastic as compared to respiratory droplets have far reaching implications for prevention and control of the virus at the population level. first, risk communication messages should emphasize the high risk constituted by surfaces such as doorknobs, stainless steel handrails, disposable plastics etc. and encourage people to refrain from unnecessary touching of such surfaces. second, regular disinfection of such surfaces at the household and community level is advised and should be included in risk communication messages and during community engagement sessions [ ] . third, in the light of new findings on asymptomatic transmission of covid- and recommendations on the usage of face masks by healthy individuals, african countries should define clear policies on the use of face masks. such policies should ensure that face masks are available to those who need them particularly the frontline healthcare workers, caregivers and vulnerable groups, address the issue of shortage of masks and other supplies which is already a challenge in many african countries and importantly provide clear guidance to the general population on the pros and cons, safe use, donning and doffing of face masks. furthermore, african scientists should pursue urgent researches into the use of locally available material for the production of face masks which are suitable to the african context [ , ] . while available scientific evidence shows that the social distancing which is the ultimate aim of the current lockdowns and population movement restriction measures instituted by several african countries may reduce transmission of the virus in the short term, this strategy alone may not be enough to break the chain of transmission [ ] . since there is already widespread community transmission in many of these countries, population confinement may result in a change in the transmission pattern from the community to the household level [ ] . furthermore, african countries may not be able to sustain such lockdowns for a long time given their socioeconomic context thus they should focus on making the best use of the small window of opportunity that they offer. first, clear objectives should be set for lockdowns which should be to reduce transmission through the scale up of preparedness and response interventions and to control the outbreak in areas of transmission. these objectives should be communicated clearly to the general population to forestall community resistance to lockdowns which is being experienced in some of the african countries. second, the definition of areas where to impose confinement should be guided by the epidemiology and pattern of transmission of the disease. third, the lockdowns should be accompanied by intensive risk communication, active case search at the community and household levels, massive testing, contact tracing and isolation. fourth, adequate preparation should be made to ensure that confined populations have access to basic services such as food, water, healthcare etc. during lockdowns in order to reduce community resistance and ensure adherence. fifth, appropriate strategies to prevent a second wave of the pandemic following the lifting of the lockdown measures should be developed and implemented [ ] . given the weak health systems in most of the infected african countries, institutional management of all laboratory confirmed cases may not be a feasible option. on the other hand, home management of such cases is constrained by several challenges due to the large household size, poor housing and high population density in many african countries. countries should therefore develop context-specific case management strategies which should classify cases according to their risk and health needs, identify places such as health facilities and non-health facilities such as repurposed hostels, schools, hotels or stadia where the various categories of cases will be isolated, define and identify the minimum package of resources such as health workers, medicines, medical equipment and other logistics which are needed to effectively manage the anticipated caseloads. such strategies should be based on the prevailing transmission scenario in the country. the covid- pandemic has overwhelmed even strong health systems in europe and america. a review and analysis of the impact of the - ebola outbreaks in west africa on health systems revealed that there was a significant reduction in access to routine health services and this led to substantially increased mortality from preventable diseases such as malaria, measles, hiv, aids and tb. african countries should learn from this experience and implement available guidance from who to ensure that essential health services are maintained during the covid- pandemic particularly during lockdowns to reduce excess mortality from other preventable diseases [ ] [ ] [ ] . key to maintenance of essential services during the covid- pandemic is the protection of health care workers from acquiring covid- infection; this can be achieved by providing african health workers with the necessary equipment, information and training on how to protect themselves [ ] . management of covid- outbreaks in the situation of population displacement such as refugee and idps camps and in prisons and urban slums which are common in africa is a major challenge. other high-risk situations include in large-scale industries which employ a large number of semi-skilled workers [ ] . the high transmissibility of the virus, overcrowding and inadequate access to social services such as water and sanitation will rapidly facilitate transmission of the virus and constrain implementation of preventive measures such as social distancing in such situations. african countries should, therefore, invest in the development of special public health strategies for prevention and control of outbreaks in such settings [ ] . establishment of covid- information and testing centres near such areas is recommended to improve rapid access of the high-risk populations to covid- prevention and control services [ ] . importantly, the lessons from the rapid spread of the virus in china, italy, iran, republic of korea and america should be a wake-up call for african countries to rapidly scale up risk communication, community engagement, and participation. the scientific evidence described above and outcomes of anthropological studies on covid- should be used as the basis for development of evidence-based and context specific risk communication messages. such risk communication messages should be focused on achieving behavioural change and tailor-made to address the several sociocultural myths, stigma, misconceptions and rumours associated with the virus, its transmission, prevention and control. african countries need to act early and decisively to avert excess morbidity and mortality due to covid- and the associated impact it could have on their economy, public health and health system. this could be achieved by using the available global scientific evidence to inform the development and implementation of context-specific covid- prevention and control strategies. given that there is currently no known cure or vaccine for the disease, such strategies should prioritize prevention and other appropriate interventions in a balanced manner. the african research community should scale up research to provide scientific information for better characterization of the epidemiology, transmission dynamics, prevention and control of the sars-cov- and other viruses on the continent. furthermore, african countries should use the opportunity of the covid- preparedness and response to systematically strengthen their health system capacity for broader and longer-term epidemic preparedness and response by using platforms such as the national action plans for health security. finally, given the chronic outlook of this pandemic, african countries should explore opportunities to mainstream ongoing covid- response interventions into existing healthcare programmes to ensure cost-effectiveness and sustainability in the long-term. detail/ - - -statement-on-the-secondmeeting-of-the-international-health-regulations accessed world health organization. who director-general's opening remarks at the media briefing on covid world health organization. coronavirus disease (covid- ) situation dashboard world health organization regional office for africa. covid- in the world health organization african region world health organization regional office for eastern mediterranean world health organization. coronavirus disease (covid- ) situation report − lessons from italy's response to coronavirus, havard business review chinese center for disease control and prevention. environmental samples from the south china seafood market in wuhan epidemiological and clinical characteristics of cases of novel coronavirus pneumonia in wuhan, china: a descriptive study clinical course and risk factors for mortality of adult inpatients with covid- in wuhan, china: a retrospective cohort study early transmission dynamics in wuhan, china, of novel coronavirus-infected pneumonia the incubation period of -ncov infections among travellers from wuhan. china euro surveill updated understanding of the outbreak of novel coronavirus ( -ncov) in wuhan modelling the epidemic trend of the novel coronavirus outbreak in china breaking down of healthcare system: mathematical modelling for controlling the novel coronavirus ( -ncov) outbreak in wuhan transmission dynamics of novel coronavirus ( -ncov) a mathematical model for simulating the phase-based transmissibility of a novel coronavirus high temperature and high humidity reduce the transmission of covid- accessed the efects of temperature and relative humidity on the viability of the sars coronavirus epidemiology, causes, clinical manifestation and diagnosis, prevention and control of coronavirus disease (covid- ) during the early outbreak period: a scoping review modes of transmission of virus causing covid- : implications for ipc precaution recommendations. scientific brief air, surface environmental, and personal protective equipment contamination by severe acute respiratory ryndrome coronavirus (sars-cov- ) from a symptomatic patient aerosol and surface stability of sars-cov- as compared with sars-cov- substantial undocumented infection facilitates the rapid dissemination of novel coronavirus (sars-cov ) how we know ending social distancing will lead to more deaths public health interventions and epidemic intensity during the influenza pandemic rational use of face masks in the covid- pandemic the-use-of-masks-in-the-community-during-home-care-andin-healthcare-settings-in-the-context-of-the-novel-coronavirus-( -ncov)-outbreak is returning to work during the covid- pandemic stressful? a study on immediate mental health status and psychoneuroimmunity prevention measures of chinese workforce immediate psychological responses and associated factors during the initial stage of the coronavirus disease (covid- ) epidemic among the general population in china a longitudinal study on the mental health of general population during the covid- epidemic in china disinfection measures for pneumonia foci infected by novel coronavirus in home care for patients with covid- presenting with mild symptoms and management of their contacts: interim guidance covid- control in low-income settings and displaced populations: what can realistically be done? effectiveness of airport screening at detecting travellers infected with novel coronavirus ( -ncov) the covid- pandemic in the us: a clinical update what's the way out? potential exit strategies from the covid- lockdown the health impact of the - ebola outbreak effects of response to - ebola outbreak on deaths from malaria, hiv/aids, and tuberculosis covid- : operational guidance for maintaining essential health services during an outbreak interim guidance coverage of health information by different sources in communities: implication for covid- epidemic response characterize health and economic vulnerabilities of workers to control the emergence of covid- in an industrial zone in vietnam we thank the global research community which has worked tirelessly to provide scientific evidence for better understanding and management of covid- . we acknowledge the support provided by victoria awuor jura in the proof reading and copy-editing of the final version of the manuscript. the authors alone are responsible for the views expressed in this article, which do not necessarily represent the views, decisions or policies of the institutions with which they are affiliated. authors' contributions ooo conceived and wrote the first draft of the manuscript. all authors read and provided significant inputs into all drafts of the manuscript, agreed to be accountable for all aspects of the work and approved the final draft of the manuscript for publication. all the authors are members of the covid- preparedness and response team of who country office, south sudan. no funding was received for this manuscript.availability of data and materials not applicable.ethics approval and consent to participate not applicable. not applicable. received: april accepted: august key: cord- -ma rwkdq authors: omonzejele, peter f. title: preserving bodily integrity of deceased patients from the novel sars-cov- pandemic in west africa date: - - journal: j bioeth inq doi: . /s - - - sha: doc_id: cord_uid: ma rwkdq the outbreak of the novel coronavirus pandemic, otherwise known as covid- brought about the use of new terminologies—new lexical items such as social distancing, self-isolation, and lockdown. in developed countries, basic social amenities to support these are taken for granted; this is not the case in west african countries. instead, those suggested safeguards against contracting covid- have exposed the infrastructural deficit in west african countries. in addition, and more profoundly, these safeguards against the disease have distorted the traditional community-individuality balance. the enforcement of social distancing, self-isolation, and lockdown has made it impossible for west africans to drift to their ancestral homes and villages, as is usually the case in times of crisis, with attendant consequences for communal life and traditional burial rites. this could be one of the reasons why some covid- patients are escaping from isolation centres, since to die in such centres violates their bodily integrity at an ontological level. the sars-cov- (hereafter referred to as pandemic that started in china in december found its way to west africa in february . this allowed most west africans to play the ostrich for about three months as they had thought the virus unlikely to survive in the warm climate of west africa. it is true, generally, that african countries have recorded fewer cases of covid- than countries in europe and america. what is not clear at the moment is if a warmer temperature is responsible for the low record of cases or simply a lack of kits for extensive testing. there is no scientific evidence to show that africans have special immunity against the virus, but at present, africa presents the least number of confirmed covid- cases compared to america, asia, and europe. according to the statistics provided by the european centre for disease prevention and control ( ) , as at june , , africa had accumulated , confirmed covid- cases, whereas asia had , , , america , , , and europe , , . covid- deaths at the same date are africa , , asia , , america , , and europe , . perhaps due to the comparatively low death rate, some people in africa have argued that there was no such thing as covid- . they have further opined that what the west refers to as covid- is just a form of acute malaria. this line of thinking might be premised on some similarities of symptoms (such as high temperature and fatigue) associated with both diseases, which in some cases have posed screening challenge (chanda-kapata et al., , - ) . this is unlike the case of the ebola epidemic, which had a distinctive haemorrhagic fever and a high fatality rate. despite the scepticism expressed by some people in sub-saharan africa about the reality of covid- , elementary epistemology teaches that there is a difference between belief and truth. for example, i couldfor whatever reason-choose to believe whatever catches my fancy. this could be true or false. however, truth or facts are independent of my belief and how i feel about something or about the truth of it. africans will have to face up to the fact that the world is dealing with a virus of a global proportion and so take appropriate steps to deal with it. in fact, most governments in africa are struggling to address challenges posed by the reality of the pandemic. the covid- pandemic has exposed the general infrastructural deficit in the region, particularly west africa, as governments in the region grapple to address the challenges it has posed. the immediate step taken by most west african leaders was to shut their air and land borders to countries with high incidences of covid- . some people, especially those of the opposition parties, have argued that the decision was taken belatedly. they argued that given the weak health infrastructure in the region, those countries ought to have acted earlier-even before they recorded any incident of the disease, as all primary cases of covid- were imported into the region. despite those attacks, regional governments took steps to place bans on public gatherings for sporting events and in worship areas, the workplace, and schools. in short, countries in the west african region were shut down. those preventive steps are similar to those taken by other countries around the world. the world health organization (who) suggested several preventive ways to avoid contracting the disease, some of which are regular handwashing with running water and soap, social (physical) distancing, and the use of alcohol-based hand-sanitizers. west african leaders keyed into this and communicated it to their citizens through print and electronic media. however, the challenge is that while some of those measures may appear commonplace and ordinary in western countries, the same cannot be said for most west african countries where these safeguards may be considered exotic and extraordinary, depending on the density of poverty in that region. the west african "region includes some of the poorest countries in the world … as nine of the poorest countries are in the region" (martinez-alvarez et al. , e ) . this means that simple safeguards such as handwashing, hand sanitizers, and so on may prove difficult in many communities. let us examine the practicality of employing those safeguards. during the ebola epidemic in western africa, the challenges associated with regular hand washing with running water were also apparent. though the who has suggested it as one of the most effective ways to prevent contracting the covid- virus, the fact remains that many west african communities do not have access to running water, especially those in rural areas (omonzejele , ) . according to the world bank report of on water and sanitation, over million people lack access to drinking water and about half of those people are in sub-saharan africa (world bank ). this means that the suggested use of handwashing against contracting covid- is not practicable for many citizens in the west african region, especially those in rural areas. the alternative, use of hand sanitizers, is also a challenge due to poverty. however, government agencies, corporate bodies and non-governmental organizations have assisted with the production and free distribution of hand-sanitizers and also face masks. it is, however, not clear whether, and to what extent, all rural dwellers benefited from the gesture. at the level of care for those who have contracted covid- , everyone knew, ab initio, it was going to constitute a challenge. within the first month of managing people for the condition, there were shortages of test kits, ventilators, personal protective equipment, and so on. at some point, the old saying that necessity is the mother of invention came to bear. for instance, in senegal, with only fifty ventilators nation-wide, scientists in collaboration with mologic, a british biotech company, "developed a covid- test kit that cost $ and a ventilator which cost $ . the kit can deliver results in minutes and can be used at home like a pregnancy kit" (oguntola ) . in comparison, imported ventilators cost $ , each. nigerian engineers and scientists in tertiary institutions have also reportedly manufactured low-cost ventilators as well. in the meantime, the chinese government, the european union business organization, and wealthy individuals have provided assistance in the form of medical equipment, technical assistance, and much-needed financial support, among other things, to build standard isolation centres. however, something unusual has continued to happen in isolation centres in nigeria and perhaps in other west african countries. some patients in the isolation centres for covid- management have either escaped or attempted to escape from those centres. instances of patients escaping from isolation centres are so rampant that nigeria's leadership newspaper devoted a special column to it. according to morphy ( ) , in the nigerian state of osun, "six persons, who had tested positive for covid- , had escaped from the isolation centre without trace." in addition, he reported that in abuja, the administrative headquarters of nigeria, "that a lady suspected to be infected with the novel coronavirus allegedly escaped from an isolation centre in abuja and was reportedly traced and arrested in akwanga, in nasarawa state." in a similar vein, "a commercial driver who tested positive to coronavirus in niger state had reportedly escaped from the isolation centre in bida." there are several instances that show that these successful and failed attempts to escape from covid- treatment centres are not isolated cases. escapes and attempts to escape by some patients from those centres have nothing to do with the quality of the isolation centres in nigeria-which meet who standards. instead, there appear to be deeper reasons for such seemingly "unreasonable" behaviour, as a patient's stay at an isolation centre does not attract any cost to the patient for medical care, nutrition, and general care. what then is the reason? one of the reasons is discoverable in the west african traditional principle of communityindividuality and traditional understanding of bodily integrity for a deceased member of a community. the phrase community-individuality was first used by iroegbu ( , ) to describe a way of life which has been in place in traditional african communities since time immemorial. he used the phrase to explain the relationship that exists between the community and the individual in the african context. speaking from a west african perspective, the human person is understood as a being in communion with others and not as an individual entity. for instance, it would be impossible to define the human person in isolation from that person's relationship with his kindred and ancestral community. a person's life is intertwined with that of his ancestral community, in life and in death, and there are ceremonies and rituals associated with them. one of the events in the life of the west african is burial rites. a burial rite is contingent upon having a corpse. corpses of deceased patients from covid- are not recoverable as they are interred by relevant government agencies to curb further transmission of the virus. this is a serious challenge for the west african mind. this is because for the west african, the human body is not a mere container but an entity of intrinsic worth. the intrinsic worth of a person is weaved into those values which are associated with all humans, such as the entitlement for all humans to be treated with respect. but in addition, another-second-layer of intrinsic worth of humans has to do with the specific talents and abilities associated with that individual. on the demise of a person, some of those attributes evaporate with the individual, except for posthumous appreciation of their achievements. the need to dispose of such a body in ceremonial rites is associated with this second level of intrinsic worth. this is the reason a more dignified public burial ceremony (this is different from traditional burial rites) is accorded a deceased prime minister over that of a peasant farmer. however, for the west african, there are other traditional rites associated with the appreciation of a deceased relative, as it is believed that such a deceased has migrated to another phase of life, where they serve as gobetween between the families and communities they left behind and the other world where the deceased now resides. for the west african, this is another level of intrinsic human worth that is only possible after physical death, especially where the deceased was elderly-and the elderly are usually the most susceptible to the covid- virus. it is not any wonder that west africans spend a lot of money as part of burial rites on a presumably "lifeless" body of a departed one. based on tangwa's ( , ) correct explanation that african themes and traditions are similar in their essentials, i will use the tradition of the esan people of nigeria to explain what constitutes traditional burial rites in western africa and the implication of its denial. on the death of an elderly man (it could be a woman): before the body was ready for burial, it was washed, a new pot being used for the water. if the dead man was well-to-do the egbele demanded the slaughtering of a goat called ebhe ihion in honour in honour of the sponge with which the body had been washed. the body was then wrapped in a new mat and brought to the front of the main building, for the ceremony with eman elinmin, the special foufou prepared simply with fish, or with goat flesh in the case of a wealthy man. the children assembled round the body that was lying with the head towards the house. on behalf of the first son, one of the iko egbele blessed the dead and cut some of the foufou at the feet. the children and all the descendants knelt beside the body and were given a bit of the food one by one. the body was then placed on a form made with seven fresh mid-ribs of palm branches. the whole corpse is then wrapped with a white piece of cloth provided by the heir. the body is then taken on the head by two men, with the feet in front. they then headed for the cemetery with the heir holding the pot that has been used during the washing. when the body has been interred a pot was placed on the tomb. (okogie , - ) there are slight variations to burial rites allowing for peculiar circumstances of the dead and communities. based on some aspects of the burial rites indicated above, it is easy to understand why someone suffering from a potentially fatal disease such as covid- will escape from management centres, as it is common knowledge that bodies of the dead are not given to family members for burial rites. though the fatality rate is low, the fact still remains that the disease is deadly and has no cure, hence, if contracted, one could die from it, and corpses of the deceased will not be released by the government for traditional burial rites. it is for this reason some people prefer to go to their villages where they resort to the use of local herbs. for them, it is considered a win-win situation. if they are healed from the use of local herbs, then, that is splendid. in the event that they succumbed to the disease, their people despite the contagious nature of the disease must of necessity devise ways to accord them traditional burial rites which will accord such bodies moral and spiritual benefits. this again is a win, for to die without traditional burial rites is inconceivable and abominable. west africans believe that the departed is still in communion with the living. this is the third level of intrinsic worth of persons. hence, it is commonplace to talk of one's ancestors and their spiritual usefulness. but it is impossible to talk of an ancestral being that did not go through the purification of traditional burial rites which accords the deceased with bodily integrity. this means that beyond the body, mind, and soul, the human body on its earthly demise and after burial rites transcends to an ontological level that mbiti referred to as "the living dead" (mbiti , - ) . in similar vein, gbenda ( , ) adds that "… the ancestors are believed to be the living-dead …they were good people in their earthly life and fulfilled societal obligations and duties, they are now spirits." but what qualifies the dead to be an ancestor, that is, "a living-dead"? oguejiofor ( , ) provided the response as: the individual must live a morally upright life. he must also be successful as a person, and his success is shown in his possession of wife (or wives) and children especially male children, and enough material possession. he must have died a good death … not of mysterious illness or by accident (onwu ekwensu). these conditions must be accompanied by a befitting burial [with which] the dead are received in the land of the spirit (ala mmuo) by his ancestors. this clearly shows that burial rites are central to the ontological transcendence to the level of the "livingdead." this in turn allows for ancestor veneration (nwanfor , - ) . these rites cannot be undertaken in the absence of a corpse and so might be responsible for the escape of patients from isolation centres. within the west african context, the community is the placenta through which the individual derives his sustenance and being. but the placenta (the community) is meaningless without the individual it nourishes. in times of crisis, such as the covid- pandemic with no known cure, one simply went back to one's ancestral community to seek remedy or cure for one's condition. in the event the person succumbs to the illness, the person at least receives a befitting burial which accords posthumous bodily respect. this is the most probable reason patients continue to escape from covid- isolation centres. since this is the most probable case for escapes from isolation centres, governments in the west african region should, perhaps, engage with the who to seek technical expertise in the decontamination of deceased people from covid- isolation centres, and then make such corpses available to their families for traditional burial rites. funding no funding support for the research. conflict of interest no conflict of interest. covid- and malaria: a symptom screening challenge for malaria endemic countries african religion and christianity in a changing world. a comparative approach european centre for disease prevention and control metaphysics: the kpim of philosophy covid- pandemic in west africa african religions and philosophy danger! covid- patients are escaping from isolation centres. leadership the living-dead (ancestors) among the igbo-african people: an interpretation of catholic sainthood eschatology, immortality and igbo philosophy of life senegal scientists develop $ covid- testing kit, $ ventilator. leadership esan native laws and customs with ethnographic studies of the esan people ethical challenges posed by the ebola virus epidemic in west africa the traditional african perception of a person: some implications for bioethics understanding poverty-water publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations key: cord- - e jrv s authors: ebinger, joseph e.; achamallah, natalie; ji, hongwei; claggett, brian l.; sun, nancy; botting, patrick; nguyen, trevor-trung; luong, eric; kim, elizabeth h.; park, eunice; liu, yunxian; rosenberry, ryan; matusov, yuri; zhao, steven; pedraza, isabel; zaman, tanzira; thompson, michael; raedschelders, koen; berg, anders h.; grein, jonathan d.; noble, paul w.; chugh, sumeet s.; bairey merz, c. noel; marbán, eduardo; van eyk, jennifer e.; solomon, scott d.; albert, christine m.; chen, peter; cheng, susan title: pre-existing traits associated with covid- illness severity date: - - journal: plos one doi: . /journal.pone. sha: doc_id: cord_uid: e jrv s importance: certain individuals, when infected by sars-cov- , tend to develop the more severe forms of covid- illness for reasons that remain unclear. objective: to determine the demographic and clinical characteristics associated with increased severity of covid- infection. design: retrospective observational study. we curated data from the electronic health record, and used multivariable logistic regression to examine the association of pre-existing traits with a covid- illness severity defined by level of required care: need for hospital admission, need for intensive care, and need for intubation. setting: a large, multihospital healthcare system in southern california. participants: all patients with confirmed covid- infection (n = ). results: of all patients studied, % required hospitalization, % required intensive care, and % required intubation. in multivariable-adjusted analyses, patients requiring a higher levels of care were more likely to be older (or . per years, p< . ), male (or . , p = . ), african american (or . , p = . ), obese (or . , p = . ), with diabetes mellitus (or . , p = . ), and with a higher comorbidity index (or . per sd, p< . ). several clinical associations were more pronounced in younger compared to older patients (p(interaction)< . ). of all hospitalized patients, males required higher levels of care (or . , p = . ) irrespective of age, race, or morbidity profile. conclusions and relevance: in our healthcare system, greater covid- illness severity is seen in patients who are older, male, african american, obese, with diabetes, and with greater overall comorbidity burden. certain comorbidities paradoxically augment risk to a greater extent in younger patients. in hospitalized patients, male sex is the main determinant of needing more intensive care. further investigation is needed to understand the mechanisms underlying these findings. a a a a a the severe acute respiratory syndrome coronavirus- (sars-cov- ) is now well recognized as the cause of the coronavirus disease (covid- ) global pandemic [ ] [ ] [ ] . the rate of rise in covid- infection and its associated outcomes in the united states is now comparable to rates observed in other severely affected countries such as china, italy, and spain [ ] [ ] [ ] [ ] [ ] [ ] [ ] . the spread of covid- in the united states has been especially pronounced in the states of california, new york, michigan, louisiana, and washington [ ] . consistently reported across all regions is the observation that, of all individuals who become infected with sars-cov- , a majority tend to have mild or no symptoms; however, an important minority will develop predominantly respiratory disease that can lead to critical illness and death [ ] [ ] [ ] [ ] . multiple, reports suggest that certain demographic and clinical characteristics may predispose infected persons to more severe manifestations of covid- , such as older age, male sex, and pre-existing hypertension, pulmonary disease, or cardiovascular disease [ , [ ] [ ] [ ] [ ] . given that these traits tend to cluster among the same persons, the relative contribution of each trait to the risk for developing more severe presentations of covid- illness remains unclear. we conducted a comprehensive investigation of the pre-existing demographic and clinical correlates of covid- illness severity observed among patients evaluated for covid- within our multi-site healthcare system in los angeles, california. we deliberately focused our study on pre-existing characteristics for two main reasons: first, we recognize that patients with covid- illness can present early or late in the disease course, causing many clinical features to vary at the time of initial clinical encounter; and, second, we anticipate that ongoing public health efforts can be informed and augmented by understanding which predisposing factors may render certain segments of the population at higher risk for the most morbid sequelae of sars-cov- infection. the cedars-sinai health system is located in los angeles, california with a diverse catchment area of . million individuals, % of whom are over the age of years and % identify as a racial or ethnic minority. the cedars-sinai health system includes cedars-sinai medical center (csmc), marina del rey hospital (mdrh), and affiliated clinics. for the current study, we included all patients who were found to have a laboratory confirmed diagnosis of sars-cov- infection while being evaluated or treated for signs or symptoms concerning for covid- at csmc or mdrh, beginning after the first confirmed case of community transmission was reported in the u.s. on february , . subsequently, the first laboratory confirmed covid- case in our health system was on march , . all laboratory testing for sars--cov- has been performed using reverse transcriptase polymerase chain reaction of extracted rna from nasopharyngeal swabs. all patient testing was performed by the los angeles department of public health until march , , at which time the csmc department of pathology and laboratory medicine began using the a � star fortitude kit . covid- real-time rt-pcr test (accelerate technologies pte ltd, singapore). for the minority of patients in our study who had sars-cov- testing performed at an outside facility ( . %), documentation of a positive test was carefully reviewed by our medical staff and considered comparable for accuracy. for all patients considered to have covid- , based on direct or documented laboratory test result and suggestive signs and/or symptoms, we obtained information from the electronic health record (ehr) and verified data for the following demographic and clinical characteristics: age at the time of diagnosis; sex; race; ethnicity; smoking status defined as current versus prior, never, or unknown; comorbidities, including obesity, as clinically assessed and documented by a provider with icd- coding; and, chronic use of angiotensin converting enzyme (ace) inhibitor or angiotensin ii receptor blocker (arb) medications. chronic use of ace or arb medications was verified by confirming presence of documented ongoing medication use in an outpatient provider's clinic note along with presence of an active outpatient prescription for the medication, both dated from prior to covid- testing. we conducted iterative quality control and quality assurance analyses on all information extracted from the ehr; all data variables included in the main analyses were verified for completeness and accuracy through manual chart review, to avoid variable missingness or potential impact of inappropriate outliers in statistical modeling. because presenting clinical measures such as vital signs and laboratory values can be highly variable, based on timing of the original clinical presentation, we elected to focus on pre-existing traits that may predispose to covid- illness severity in a manner less dependent on the timing of patients presenting to medical care. to capture variation in relative comorbid status, in a way that is not captured by distinct medical history variables alone, we calculated the elixhauser comorbidity index (eci) with van walraven weighting for all patients based on all available clinical data [ ] [ ] [ ] [ ] . the eci uses categories to quantify a patient's burden of comorbid conditions and has been shown to outperform other indices in predicting adverse outcomes (s table) [ ] [ ] [ ] [ ] [ ] [ ] [ ] . for patients admitted to the hospital, length of stay, admission to an intensive care unit (icu) and death were ascertained from time stamps recorded for admission, unit transfers, and discharge. interventions such as intubation and prone positioning were identified through time stamped orders in the ehr and verified by manual chart review. dates and times of onset for reported or observed relevant signs and/or symptoms were also determined via manual chart review. all care was provided at the discretion of the treating physicians. our outcomes for this study included: severe illness (defined as requiring any kind of hospital admission), critical illness (defined as the need for intensive care during hospitalization), and respiratory failure (defined as the need for intubation and mechanical ventilation). the csmc institutional review board approved all protocols for the current study and waived the requirement for informed consent. for the total sample of covid- patients, we used parametric tests to compare normally distributed continuous variables and non-normally distributed or categorical variables, respectively. we also used histograms to display age and sex distribution for the total cohort, the patients admitted but not requiring intensive care, and patients requiring intensive care at any time during hospitalization, and the patient requiring intubation and mechanical ventilation at any time during hospitalization. we used ordinal logistic regression to examine the associations between pre-existing characteristics (based on clinically relevant, non-missing data) and a primary outcome measure of illness severity, defined as an illness severity score. we constructed the illness severity score, with higher values assigned to needing more intensive levels of clinical care, based on the following stepwise categories: = clinically deemed to not require admission; = required hospital admission but never required intensive care; = required intensive level care but never intubation; and, = required intubation during hospitalization. we constructed age-and sex-adjusted models, from which significantly associated covariates (based on p< . ) were selected for inclusion in the final multivariable-adjusted models, where appropriate (i.e. smaller sample sizes). race was treated as a binary covariate: african american and non-african american. this approach was selected given the recently reported concerns of excess risk for african americans [ ] , along with limited understanding of whether or not comorbidities contribute to this risk, in addition to the sample size for other race groups being too small for certain comparisons. because hypertension and diabetes are not calculated as substantial contributors to the elixhauser comorbidity index, we included each of these traits as separate additional covariates in all multivariable-adjusted analyses. we calculated the variance inflation factor (vif) for each of the predictor variables to confirm absence of any substantial multicollinearity. in secondary analyses, we analyzed the associations of pre-existing patient characteristics with the distinct outcomes of needing any hospital admission (severe illness) and, in the cohort of all hospitalized patients representing an especially vulnerable population, the need for intensive care (critical illness) or intubation (respiratory failure). all analyses were performed using r, version . . (r foundation for statistical computing) and stata, version (statacorp). for all final models, p values were -sided and considered significant at threshold level of . . regional analyses showed that patients presented to our healthcare system from across a broad geographic catchment area in los angeles county (s fig) . the demographic and clinical characteristics of all patients in our study sample are shown in table . of all patients with pharmacologically treated hypertension, a minority were taking ace inhibitor or arb class agents and a majority were taking anti-hypertensive medications from alternate classes. overall, almost half of patients (n = , %) were clinically assessed to require hospital admission, of whom over a third (n = ; %) required intensive care and almost a quarter ( . %) required intubation. in unadjusted analyses, the patients who were more likely to require higher levels of care tended to be older, male, african american, and with known hypertension, diabetes mellitus, higher elixhauser comorbidity index, and have prior myocardial infarction or heart failure ( table ). the number of men with confirmed covid- infection outnumbered women in nearly all age groups; this sex difference was more pronounced among patients requiring hospitalization and particularly among patients requiring intensive care or intubation (fig ) . we also observed a consistently higher rate of greater illness severity among african americans compared to persons of other racial groups (fig ) . for the primary outcome of illness severity, categorized by escalating levels of care (i.e., hospitalization, intensive care, intubation), the pre-existing characteristics that demonstrated statistical significance in age-and sex-adjusted models included older age, male sex, african american race, obesity, hypertension, diabetes mellitus, and the elixhauser comorbidity score ( table ; fig ) . the associations that remained significant in the fully-adjusted multivariable model included older age (odds ratio [or] . per years, % confidence interval [ci] . - . , p< . ), male sex (or . , % ci . - . , p = . ), african american race (or . , % ci . - . , p = . ), obesity (or . , % ci . - . , p = . ), diabetes mellitus (or . , % ci . - . , p = . ) and the comorbidity score (or . per sd, % ci . - . , p< . ). we also observed a trend towards lower severity of illness among patients chronically treated with ace inhibitor therapy, with or . ( % ci . - . ; p = . ). each estimated or value represents the increment in higher (or lower) odds of a patient requiring a next higher level of care, for every unit difference in a continuous variable (e.g. per years of age) or for presence versus absence of a given categorical variable (e.g. male sex). in effect, every years of older age was associated with~ . -fold higher odds of requiring a higher level of care, and being male versus female was associated with a~ -fold higher odds of requiring higher level care. we used the brant method to test the proportional odds assumption for consistency of associations across our ordinal outcome; these analyses revealed no substantial qualitative violations, but did indicate that the elixhauser score was predominantly associated with the specific outcomes of admission versus non-admission (or . , p< . ) and need for intensive care versus no intensive care need (or . , p = . ) that with the less frequent outcome of needing intubation versus no need for intubation (or . , p = . ). for the specific outcome of needing any hospital admission, the pre-admission characteristics that demonstrated statistical significance included older age, male sex, african american race, obesity, hypertension, diabetes mellitus, the elixhauser comorbidity index, and prior myocardial infarction or heart failure (s table) . in the multivariable model adjusting for all key covariates, the pre-existing traits that remained significantly associated with needing any hospital admission were older age, diabetes mellitus, and higher comorbidity index. among the patients whose illness severity required hospitalization, male sex was associated with the outcome of requiring further escalating levels of care (i.e., intensive care and intubation) ( table ; fig ) . in the multivariable model adjusting for key covariates, male sex remained the single most important risk marker of requiring higher-level care (or . , % ci . - . , p = . ). the results for male sex were similar for the individual outcomes of requiring intensive care or intubation (s table) . we again observed a trend towards lower need for admission to the intensive care unit among patients chronically taking an ace inhibitor (or . , % ci . - . , p = . ), and greater need for intubation among african americans patients (or . , % ci . - . , p = . ). in secondary analyses, we used multiplicative interaction terms to assess for effect modification for associations observed in the main analyses (s table) . while considered exploratory pre-existing traits associated with covid- illness severity or hypothesis generating analyses, we found several interactions of potential interest (fig ) . in particular, the associations of hispanic ethnicity, obesity, diabetes, and elixhauser comorbidity index with the primary outcome appeared paradoxically more pronounced in younger compared to older individuals (s table) . by contrast, the primary outcome was more pronounced among older compared to younger african americans. also paradoxically, hypertension appeared associated with greater risk in non-obese patient and with lower risk in obese patients. we repeated all main analyses with additional adjustment for smoking status in the subset of patients with available data on smoking; in these models, all significant results remained unchanged (s and s tables). we examined the pre-existing characteristics associated with severity of covid- illness, as observed thus far in our healthcare system located in los angeles, california. we found that almost half of patients presenting for evaluation and then confirmed to have covid- were clinically assessed to require hospital admission. these higher risk individuals were more likely to be older, male, african american, obese, and have diabetes mellitus in addition to a greater overall burden of medical comorbidities. notably, chronic use of an ace inhibitor appeared related to lower illness severity, in the absence of a similar finding for arb use. among all individuals requiring inpatient care for covid- , male patients had a greater than . -fold odds of needing intensive care and a . -fold odds of needing intubation. all of our findings were observed even after accounting for co-existing risk factors and chronic medical conditions. recognizing that patients with covid- illness can present with clinical features that vary based on timing of the index encounter, we sought to identify the pre-existing traits that render some individuals at highest risk for developing the more severe forms of covid- illness once contracted. in our u.s. based metropolitan community, we observed that both obesity and diabetes mellitus are predisposing factors associated with a greater odds of needing hospital admission for covid- but not of requiring further escalation of care; this finding is consistent with emerging reports of obesity and diabetes mellitus each being associated with a greater risk for pneumonia due to covid- as well as other community-acquired viral agents-particularly in areas of the world where obesity is prevalent [ ] [ ] [ ] [ ] [ ] [ ] . also consistent with worldwide reports, we observed that older age is a significant predisposing risk factor for greater covid- illness severity in multivariable-adjusted models; this finding may represent an age-related immune susceptibility that is not completely captured by even a comprehensive comorbidity measure such as the elixhauser index. notwithstanding an overall age association in the expected direction of risk, we also found a paradoxical age interaction for certain key correlates. in effect, presence of obesity, diabetes, or an elevated overall comorbidity index were each associated with greater covid- illness severity in younger (i.e. < years) compared to older age groups. while unexpected, this finding is actually consistent with the known reduction of ace expression with advancing age, a phenomenon that has been proposed as a major contributor to the broad susceptibility to covid- seen in younger to middle aged individuals across the population at large [ ] . consistent with worldwide reports, we found that the association of male sex with greater odds for every metric of covid- illness severity was especially prominent-and this was not explained by age variation, risk factors, or comorbidities [ ] . reasons for the male predominance of illness severity remain unclear. although ace genetic expression is on the x chromosome, evidence to date would suggest relatively comparable expression levels between sexes relative risks associated with illness severity score are shown for all associations observed in the total sample (n = ), stratified by subgroups defined by age (younger vs. older than median age years), sex, and obesity (bmi � kg/m ). � the primary outcome of covid- illness severity score in the total sample was defined as an ordinal variable wherein: = referent, = required admission but never icu level care, = required icu level care but never intubated, = required intubation. �� p for interaction values were calculated from likelihood ratio test between models with and without the interaction term. for each variable in the list, age (