key: cord-0690156-xbwdzbfy authors: Reuben, Rine Christopher; Gyar, Silas Dogara; Makut, Makwin Danladi; Adoga, Moses P. title: Co-epidemics: Have measures against COVID-19 helped to reduce Lassa fever cases in Nigeria? date: 2021-02-16 journal: New Microbes New Infect DOI: 10.1016/j.nmni.2021.100851 sha: d3e79b912374ff4bec5a9584db13852959357ed1 doc_id: 690156 cord_uid: xbwdzbfy While the COVID-19 pandemic wreaks multiple devastating public health and socio-economic havocs across the world, Nigeria alongside other West African countries is simultaneously faced with recurrent Lassa fever epidemic. The complicating scenario is the similarity in the clinical manifestation of both COVID-19 and Lassa fever, making a significant risk in the misdiagnosis of the initial presentation of both diseases with an increased likelihood of coinfection. However, the strict implementation of COVID-19 infection prevention and control (IPC) measures across Nigeria after the initial outbreaks concurrently resulted in the reduction of Lassa fever cases. The abrupt change in the behavior of Lassa fever epidemiological data which are attributable to the implementation of COVID-19 IPC measures at the national, sub-national and community levels requires detailed investigation during and after the COVID-19 epidemic to elucidate the interactions and evolutionary dynamics Lassa fever cases in Nigeria. Currently, the coronavirus disease caused by the novel SARS-CoV-2 virus emerging from Wuhan, China has spread across 216 countries, areas or territories of the world as a pandemic with multiple devastating public health and socio-economic implications [1] . One of the public health implications of COVID-19 in West Africa and Nigeria in particular is the continuous Lassa fever epidemic that has recurred unabatedly in the last decades. This period of COVID-19 pandemic coincides with another Lassa fever epidemic comprising a further increase in cases. COVID-19 in Nigeria has reached 56,256 confirmed cases with 1,082 deaths nationwide and a case fatality ratio (CFR) of 1.9% [2] while Lassa fever reached 1078 confirmed cases with 225 deaths and 20.9% CFR [3] . Lassa fever is a severe and zoonotic viral haemorrhagic disease caused by Lassa virus, a singlestranded RNA virus belonging to the Arenaviridae family. Since its emergence in 1968 from Lassa, a town in north-eastern Nigeria, this virus has spread across Nigeria and the West Africa region causing severe outbreaks annually [4] . Human transmission of this virus occurs primarily through contact with contaminated excrements or body secretions of the virus natural reservoir, Mastomys natalensis (Multimammate rat) or secondarily through human-to-human transmission and hospital-acquired infection through contact with blood, secretions and excretions of infected persons [5] . Out of the 36 states in Nigeria, 27 including the Federal Capital Territory (FCT) are already affected with Lassa fever with the highest number of cases recurrently occurring during the dry season (November-April) [6] . Furthermore, about 300,000-500,000 Lassa fever cases occur annually in West Africa with over 5000 deaths [7] . Within the last decade, there has been a steady rise in the incidence of Lassa fever not only in Nigeria but the entire West African subregion. Together with other nations of the world, Nigeria is currently facing a COVID-19 epidemic, with the index case reported on 27 th February 2020 [2] . Annually, the incidence of Lassa fever tends to increase from the later months of the rainy season and then peaks between March to May. This recurrent temporal pattern associated with Lassa fever means that the COVID-19 epidemic began shortly before Lassa fever reached its seasonal peak in Nigeria thus resulting in COVID-19 and J o u r n a l P r e -p r o o f Lassa fever co-epidemics [8] . During the epidemiological week 9 of 2020 when the first confirmed case of COVID-19 was reported in Nigeria, there was already an increase in the number of confirmed Lassa fever cases reportedly affecting 27 states, exceeding the number of cases reported in 2019 during the corresponding week [3] . The increased number of cases from the 2019 Lassa fever epidemic could have possibly resulted in a higher number of cases and the early rise of Lassa fever in 2020, with higher notifications than the average in the preceding year. Epidemiological data obtained from week 9 of 2020 showed Edo, Ondo and Taraba states are the epicenters of Lassa fever, having the highest number of cases (Figure 1 ; Table1). Although Edo and Ondo states are coincidentally among the states worse stricken with the COVID-19 epidemic in Nigeria, however, curiously, after epidemiological week 36 of 2020, there was a significant decrease in the number of Lassa fever cases ( Figure 1 . Table 3 ), coinciding with the implementation and intensification of the COVID-19 prevention and control measures both by the states and federal governments respectively. The decrease in Lassa fever cases in the abovementioned states became noticeable in late April 2020 ( Figure 1 ; Table3), the peak of recurrent Lassa fever outbreaks in Nigeria [3] . Long before the COVID-19 emergence, the WHO opined that due to weakened infection prevention and control (IPC) measures at the sub-national levels, Nigeria's capacity to effectively manage and control Lassa fever remains suboptimal [6] . However, to effectively mitigate the spread of COVID-19, strict implementation of COVID-19 control and prevention measures including social distancing, national lockdown, improved personal hygiene, avoidance of person-to-person contact, use of face masks, the prohibition of public transport and inter-states travels among others were implemented across the country [9] . The science of the relationship between the intensification, implementation and community adherence to COVID-19 IPC measures and the decrease in Lassa fever cases require further detailed epidemiological studies to fully comprehend such epidemiological relationships and dynamics. All countries of the world are presently battling against COVID-19. Therefore, the further epidemic of Lassa fever in Nigeria will pose tremendous challenges for the effective containment More importantly, the clinical similarities existing in the presentation of patients with COVID-19 and Lassa fever including fever, headache, general weakness, malaise, sore throat and cough from the onset of both infections to pneumonia, breathing difficulty, diarrhoea, disorientation, abdominal pain, low blood pressure, tremor, seizures, coma and multiple organ dysfunction at the later or severe stage [5, 14, 15] complicate things further. While some clinical signs and symptoms in a case series scale may initially point to COVID-19 or Lassa fever, this predictive and initial clinical variability should not be misplaced for validly guaranteed laboratory diagnosis. In some instances, the initial clinical manifestation of COVID-19 presents as fever together with joint and muscle pains, and general weakness without respiratory symptoms [16] [17] [18] thus mimicking Lassa fever presentation. Therefore, patients reporting to hospitals must be properly examined and explored for both diseases. Given the abrupt change in the behavior of Lassa fever epidemiological data which is a digression from the annual recurrent trend with Lassa fever outbreaks in Nigeria, some major hypotheses can be urgently raised. The first and most obvious is the underreporting or undernotification of Lassa fever cases as we observed in our previous work [8] . This sudden decrease of Lassa fever cases could be attributable to the swift change in focus and disease surveillance by the government in mobilizing resources, agencies and personnel to urgently respond to COVID-19 emergence after the confirmation of the initial cases in Nigeria. These immediate steps taken by the governments at all levels could have led to delay or underreporting of Lassa fever cases both at the national and sub-national levels. Furthermore, since Lassa fever and COVID-19 share similar clinical features as such, most of the febrile Lassa fever cases might have overlapped with COVID-19 cases in health centers [5, 14] . Since these 2 viral infections have similar diagnoses including reverse transcriptase-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA) and other rapid serological detection assays, the possibility of misdiagnosis of these infections cannot be overemphasized. Pseudo-serologic laboratory results for Lassa fever in COVID-19 patients and conversely could further have led to severe public health implications. Additionally, there is a need for health professionals to report suspected cases of both outbreaks pari passu. An emerging challenge within the Nigerian health care system is the proper understanding of the progression of the "masked" or "underestimated" Lassa fever epidemic with the simultaneous occurrence of "overhyped" COVID-19 epidemic. Another hypothesis is the reduction of Lassa fever morbidity as a result of the implementation of strict COVID-19 IPC measures including social distancing, national lockdown, improved personal hygiene, avoidance of person-to-person contact, use of face masks and prohibition of inter-states travels among others [9] . This could have helped to reduce Lassa fever true incidence in Nigeria hence mitigating the 2020 epidemic. Population movements, social interactions and personal hygiene are known to be major drivers for the sustenance of epidemics [19] . The recurrent Lassa fever outbreaks are often mediated by poor community hygiene which supports rodents' infestation of homes, inadequate personal hygiene, travels to epicenters and Lassa fever prone areas, contact with infected persons, and nosocomially, mostly involving health care workers [5] . The decrease in the incidence of Lassa fever after epidemiological week 36 of 2020 especially from states previously worse stricken may be attributed to decreased Lassa fever morbidity resulting from the COVID-19 IPC measures strictly implemented at the national and sub-national and community levels. The general adoption of these COVID-19 IPC measures across Nigeria may have significantly altered the epidemiological patterns of transmission of the Lassa fever virus hence reducing the number of cases. At the community and population levels, social distancing had been reported to greatly reduce pathogen transmission [20] . The social distancing scenario currently explored potentiates the opportunity of testing this hypothesis which may be used to improve Lassa fever IPC measures at the national, sub-national and community levels. However, in-depth studies during and after the COVID-19 epidemic are necessary to consider the impact of population mobility and interactions data and evolution of the frequencies of Lassa fever cases in Nigeria. From our previous epidemiological study assessing the knowledge, attitudes and practices regarding COVID-19 in Nigeria, 45.3% of the respondents held that prayer is also a potent measure for COVID-19 control and prevention [23] . In a similar study, Olapegba and colleagues [24] reported how the majority of the respondents maintained that prayer and religious beliefs could mitigate the COVID-19 epidemic in Nigeria. This agrees with the stern religious adherence and beliefs by the vast majority of the Nigerian population, making them resort to religious rituals and prayers without reporting suspected cases of disease or seeking medical attention. The observation and reports reinforced the hypothesis indicating a relationship between religious beliefs and the reduction of disease notification and/or reportage. This behavioral pattern noticed among the Nigerian population transcends beyond the COVID-19 epidemic but could be exhibited to other epidemics including the recurrent Lassa fever epidemics. Lassa fever endemic countries including Nigeria are at high risk of increasing cases of coinfection and prolonged co-epidemics so long as COVID-19 and Lassa viruses coexist and actively circulate within the population. Mitigating these viral diseases requires concerted and J o u r n a l P r e -p r o o f effective public health campaigns and strict implementation of IPC measures with the population eliminating Multimammate rats' infestation of homes, improved community and personal hygiene, use of face masks and the practice of social distancing. Nigerian health care systems should be organized to provide quality care including concurrent diagnoses of both COVID-19 and Lassa fever to individuals suspected of having either of these diseases or febrile patients without unnecessary delays due to constraints emanating from the COVID-19 pandemic. None exist. 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Nigerian Centre for disease control (NCDC) COVID-19 guideline Stung by dengue, patient dies of coronavirus co infection in Bhopal Coinfection, coepidemics of COVID 19, and dengue in dengue endemic countries: A serious health concern COVID-19 and dengue: a deadly duo Covert COVID 19 and false positive dengue serology in Singapore World Health Organization (WHO) World Health Organization (WHO) Clinical characteristics of COVID-19 in children compared with adults in Shandong Province Digestive Symptoms in COVID-19 Patients With Mild Disease Severity: Clinical Presentation, Stool Viral RNA Testing, and Outcomes COVID-19 patients' clinical characteristics, discharge rate, and fatality rate of meta-analysis Emerging infections: a perpetual challenge The effect of control strategies to reduce social mixing on outcomes of the COVID-19 epidemic in Wuhan, China: a modelling study COVID-19: Many people on the run in Lagos after testing positive -Commissioner Nigeria can't beat COVID-19 with patients fleeing isolation centresin Punch Attitudes and Practices Towards COVID-19: An Epidemiological Survey in North-Central Nigeria A preliminary assess-ment of novel coronavirus (COVID-19) knowledge and perceptions in Nigeria The authors have over the years been working on emerging and reemerging zoonotic viral pathogens including Lassa, Ebola and more recently, COVID-19 viruses. They are faculty members and practicing public health microbiologists.J o u r n a l P r e -p r o o f