key: cord-0822490-0yd16rbm authors: Farkas, Kata; Hillary, Luke S.; Malham, Shelagh K.; McDonald, James E.; Jones, David L. title: Wastewater and public health: the potential of wastewater surveillance for monitoring COVID-19 date: 2020-06-12 journal: Curr Opin Environ Sci Health DOI: 10.1016/j.coesh.2020.06.001 sha: c41d403435b07d56cd34f0d60b72910c6a740cb6 doc_id: 822490 cord_uid: 0yd16rbm Pathogenic viruses represent one of the greatest threats to human wellbeing. As evidenced by the COVID-19 global pandemic, however, halting the spread of highly contagious diseases is notoriously difficult. Successful control strategies therefore have to rely on effective surveillance. Here we describe how monitoring wastewater from urban areas can be used to detect the arrival and subsequent decline of pathogens, such as SARS-CoV-2. As the amount of virus shed in faeces and urine varies largely from person to person, it is very difficult to quantitatively determine the number of people who are infected in the population. More research on the surveillance of viruses in wastewater using accurate and validated methods and subsequent risk analysis and modelling is paramount in understanding the dynamics of viral outbreaks. Recent decades have seen a marked rise in the number of novel and emerging human pathogenic 27 viruses. This has resulted in a range of globally significant outbreaks and epidemics and a major loss 28 of life. Examples include the SARS coronavirus (SARS-CoV-1) epidemic in 2003 with over 8,000 cases 29 in 29 countries, the H1N1 influenza pandemic in 2009-10 with 60 million cases in 214 countries, and 30 the MERS coronavirus epidemic in 2012-15 with approx. 2,500 cases in 27 countries (www.who.int). 31 In December 2019, an outbreak related to a novel coronavirus (SARS-CoV-2) was reported in China 32 which has been rapidly spreading globally with over 6 million confirmed cases and over 376,000 33 deaths by 2 nd June, 2020 [1] . 34 Due to the often high infectivity and rapid transmission of viruses, individual screening in clinical 35 settings is often challenging. In addition, cases with mild or no symptoms are often overlooked, and 36 hence epidemiological models and assessments of disease prevalence may be inaccurate. There is 37 therefore a greater need to understand the spread of viral diseases at a community level which 38 would provide information for the timely mitigation of outbreaks. 39 Municipal wastewater harbours a great variety of pathogenic viruses [2] . Extensive research has 40 been undertaken on the persistence of human enteric viruses (e.g. noroviruses, enteroviruses, 41 adenoviruses, rotaviruses, hepatitis A/E viruses), transmitted via the faecal-oral route, in wastewater 42 and in the aquatic environment [3] . Enveloped viruses (e.g. coronaviruses), which rapidly inactivate 43 without a host, have also been found in wastewater [3] . Temporal changes in viral concentrations in 44 wastewater can therefore indicate the presence or absence of a virus, related outbreaks in the 45 population, and their effect on public health. Hence, domestic wastewater monitoring may be an 46 important tool to assess and mitigate viral outbreaks in a community. In this review, we aim to 47 critically assess the recent efforts on using wastewater surveillance to represent public health, with a 48 focus on SARS-CoV-2 surveillance. 49 2. The current toolbox for wastewater viral monitoring 50 2.1 Wastewater concentration for virus detection 51 For the sensitive detection of viruses in wastewater, samples are often concentrated prior to 52 quantification. Many different approaches are commonly used, as recently reviewed [4, 5] . For the 53 surveillance of SARS-CoV-2, wastewater samples are often centrifuged or filtered to eliminate debris, 54 followed by electronegative membrane filtration [6], ultrafiltration [6-11] or polyethylene glycol 55 precipitation [8, 9, 12, 13] , aluminium flocculation [14, 15] inexpensive and easy to set up, however, they may be time consuming and difficult to perform with 59 high sample throughput, especially when high turbidity samples are processed. The main 60 disadvantage of these methods is the co-concentration of organic compounds (e.g. humic 61 substances), which often interfere with downstream virus detection or in vitro studies. Furthermore, 62 concentration efficiency may vary among different samples, however, it has only been assessed in 63 two studies aiming to detect SARS-CoV-2 in wastewater [7, 15] , suggesting 3-50% viral recoveries 64 (Table 1) . Therefore, appropriate process controls, e.g. viruses of the same family or genus should 65 be added to the sample to estimate viral recoveries [15] . Alternatively, the concentration of a viral 66 indicator, which is present in wastewater at high concentrations (e.g. gut-associated phages), can be 67 compared between unprocessed and processed samples to assess concentration efficiency [7] . 68 The most widely used methods for quantification of DNA and RNA viruses in wastewater are 70 quantitative PCR (qPCR) and quantitative reverse transcription PCR (qRT-PCR), respectively [4, 19] . 71 These methods detect a small segment of the viral genome, enabling rapid, sensitive and accurate 72 strain-level detection of up to five targets in one assay [20] . Several qRT-PCR assays have been 73 designed for the detection of SARS-CoV-2 [21-24], which are suitable for wastewater monitoring 74 [6, 7, 12, 16] , however, the performance of the different assays may vary. Substantial differences in 75 viral detection rates were observed when different primer/probes were used for quantification. For 76 example, the 'N2' assay did not detect SARS-CoV-2 in wastewater samples which were positive for 77 the 'N1' and 'N3' genes [7] , hence the use of multiple primer/probe sets is recommended. A 78 limitation of qPCR-based approaches is that the reverse transcription and polymerase enzymes are 79 often inhibited by organic co-contaminants, which are concentrated and extracted together with the 80 targets. 81 Recently, digital PCR (dPCR) -based approaches have also been used for viral detection in 82 environmental samples [19] . These methods enable the absolute quantification of the targets and 83 are less sensitive to inhibition, however more expensive than qPCR-based assays. Other emerging 84 technologies, including isothermal amplification and biosensors, are also suitable for viral RNA/DNA 85 detection and quantification in environmental samples, providing results within an hour [19] . Simple 86 and affordable platforms (e.g. paper-based microfluidics devices) also have great potential for rapid, Viral metagenomics of wastewater has been widely used to monitor the prevalence of multiple 100 pathogens and could be used as an early warning system for the detection of outbreaks of novel 101 viral pathogens [29, 30] . For example, a high-throughput sequencing approach was used as an 102 alternative to q(RT-)PCR to explore the diversity of enterovirus D, hepatitis A and hepatitis E viruses 103 [31] and mastadenovirus [32] in wastewater to assess the viral strains circulating in local populations 104 of France and Australia, respectively. It may also be useful to monitor other respiratory viruses (e.g. (Table 1) . No SARS-CoV-2 was reported in wastewater prior to the first cases [7], however, 120 there is some indication that SARS-CoV-2 was present in wastewater at Amersfoort, the Netherlands 121 days before the first cases were reported [38] . When the temporal changes in SARS-CoV-2 titres 122 were assessed, viral concentrations showed good correlations with the number of COVID-19 cases in 123 the community [14, 16, 17] . Consequently, wastewater-based epidemiology may find future 124 application as an early warning system for virus outbreaks, to monitor the progression of viral 125 outbreaks, and in the provision of viral genomic data at the population scale. 126 4. Implications for the wider environment 127 Five studies have investigated viral titres in treated wastewater and three of those have found SARS-128 CoV-2 RNA in effluent with concentrations up to 10 4 gc/100ml, suggesting 1-2 log 10 removal during 129 wastewater treatment [13, 15, 16] . Whether this poses a major risk to the wider environment 130 remains unclear. However, recent reports suggest that SARS-CoV-2 can also infect and replicate in 131 semiaquatic secondary animal vectors such as mink [39, 40] . This offers the potential for animals 132 close to wastewater outlets to readily come into contact with SARS-CoV-2 from which it would likely 133 become endemic in the secondary host. This is most likely to occur from the discharge of untreated 134 sewage or from poorly treated wastewater close to watercourses (e.g. septic tanks). SARS-CoV-2 in wastewater is therefore ideally suited to describe the spatial and temporal trends in 146 disease incidence. Wastewater-based epidemiology may be useful to identify emerging and re-147 emerging pathogens in a community and may serve as an early warning system, which would be 8 useful for public health mitigation [42, 43] . However, translating the viral titres from wastewater 149 into the actual number of cases within a community is highly challenging, if not impossible. This type 150 of calculation relies on many assumptions, which still remain poorly quantified (e.g. the amount and 151 dynamics of viral shedding in faeces, viral persistence in the sewer network, variation in wastewater 152 flow due to climate etc). In addition, while suited to large urban communities (i.e. populations 153 >10,000), the approach is less well suited from an economic and logistical perspective to disparate 154 rural communities which may have hundreds of small water treatment facilities. 155 Although wastewater surveillance of SARS-CoV-2 provides a powerful tool to evaluate disease 156 incidence at the community level, it is clear that they also need to be integrated into other WHO: Coronavirus disease 2019 (COVID-19) Situation report. World Heal Organ 2020 Viromic 199 analysis of wastewater input to a river catchment reveals a diverse assemblage of RNA New trends in food-and waterborne viral outbreaks A review on 203 recent progress in the detection methods and prevalence of human enteric viruses in 204 water Recent trends on methods for the concentration of viruses from 206 water samples First confirmed detection of SARS-CoV-2 in untreated wastewater in 209 Australia: A proof of concept for the wastewater surveillance of COVID-19 in the 210 community Presence of SARS-Coronavirus-2 in sewage Regressing SARS-CoV-2 sewage measurements onto COVID-19 burden 215 in the population: a proof-of-concept for quantitative environmental surveillance SARS-CoV-2 Detection in 218 221 Temporal detection and phylogenetic assessment of SARS-CoV-2 in municipal wastewater Lema 224 JM: The fate of SARS-CoV-2 in wastewater treatment plants points out the sludge line as a 225 suitable spot for incidence monitoring 227 SARS-CoV-2 titers in wastewater are higher than expected from clinically confirmed cases Potential 230 spreading risks and disinfection challenges of medical wastewater by the presence of 231 Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) viral RNA in septic tanks of 232 fangcang hospital Wastewater Analysis for COVID-19 Epidemiological Surveillance SARS-CoV-2 237 RNA in wastewater anticipated COVID-19 occurrence in a low prevalence area Time course 240 enterovirus diversity in wastewater by ultra-deep sequencing: An effective complementary 284 tool for clinical enterovirus surveillance Genetic diversity and quantification of human 286 mastadenoviruses in wastewater from Sydney and Melbourne First detection of SARS-CoV-2 in untreated wastewaters in Italy Seasonal and spatial dynamics of enteric viruses in 293 wastewater and in riverine and estuarine receiving waters Detection of Hepatitis E Virus in Sewage After an Outbreak on a French Island Monitoring human enteric viruses in 300 wastewater and relevance to infections encountered in the clinical setting: A one-year 301 experiment in central France Detection of Enterovirus D68 in 303 wastewater samples from the United Kingdom during outbreaks reported globally between 304 How sewage could reveal true scale of coronavirus outbreak Infection and Rapid Transmission of SARS-CoV-2 in Ferrets SARS-CoV2 infection in farmed mink A review of 314 infectious disease surveillance to inform public health action against the novel coronavirus 315 SARS-CoV Future Perspectives of Wastewater-Based Epidemiology: 317 Monitoring Infectious Disease Spread and Resistance to the Community Level Wastewater-Based Epidemiology for Early Detection of Viral 320 Women in Water Quality Geographical tracking and mapping of coronavirus disease 323 COVID-19/severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic and 324 associated events around the world: how 21st century GIS technologies are supporting the 325 global fight against outbr (Ahmed et al., 2020) Centricon (Merck) ultrafiltration of centrifugated supernatant N_Sarbecco: 1/9 NIID_2019-nCOV_N: 0/9 ☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.☐The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: