key: cord-0692284-eyf2dogw
authors: La Rosa, Giuseppina; Bonadonna, Lucia; Lucentini, Luca; Kenmoe, Sebastien; Suffredini, Elisabetta
title: Coronavirus in water environments: Occurrence, persistence and concentration methods - A scoping review
date: 2020-04-28
journal: Water Res
DOI: 10.1016/j.watres.2020.115899
sha: 5b6b23d6d9785a64c65390921c4270973d1a4455
doc_id: 692284
cord_uid: eyf2dogw

Abstract Coronaviruses (CoV) are a large family of viruses causing a spectrum of disease ranging from the common cold to more severe diseases as Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV). The recent outbreak of coronavirus disease 2019 (COVID-19) has become a public health emergency worldwide. SARS-CoV-2, the virus responsible for COVID-19, is spread by human-to-human transmission via droplets or direct contact. However, since SARS-CoV-2 (as well as other coronaviruses) has been found in the fecal samples and anal swabs of some patients, the possibility of fecal-oral (including waterborne) transmission need to be investigated and clarified. This scoping review was conducted to summarize research data on CoV in water environments. A literature survey was conducted using the electronic databases PubMed, EMBASE, and Web Science Core Collection. This comprehensive research yielded more than 3000 records, but only 12 met the criteria and were included and discussed in this review. In detail, the review captured relevant studies investigating three main areas: 1) CoV persistence/survival in waters; 2) CoV occurrence in water environments; 3) methods for recovery of CoV from waters. The data available suggest that: i) CoV seems to have a low stability in the environment and is very sensitive to oxidants, like chlorine; ii) CoV appears to be inactivated significantly faster in water than non-enveloped human enteric viruses with known waterborne transmission; iii) temperature is an important factor influencing viral survival (the titer of infectious virus declines more rapidly at 23°C–25 °C than at 4 °C); iv) there is no current evidence that human coronaviruses are present in surface or ground waters or are transmitted through contaminated drinking-water; v) further research is needed to adapt to enveloped viruses the methods commonly used for sampling and concentration of enteric, non enveloped viruses from water environments. The evidence-based knowledge reported in this paper is useful to support risk analysis processes within the drinking and wastewater chain (i.e., water and sanitation safety planning) to protect human health from exposure to coronavirus through water.

Faecal contamination of water supplies has been historically recognised as a risk for human health: Haramoto et al., 2018; La Rosa et al., 2012; Moreira and Bondelind; Rusinol, and Girones, 2017; 58 WHO 2017). Viruses of concern for their potential waterborne transmission belong mainly to the 59 group of enteric viruses, a diverse group of non-enveloped viruses, which can multiply in the 60 gastrointestinal tract of humans. They can be mostly responsible of gastrointestinal illness, but also complex of Amoy Garden in Hong Kong, transmission by aerosolized wastewater was suspected 95 (McKinney et al., 2006) . 96 In late 2019, a new acute respiratory disease known as COVID-19, sustained by a novel 97 coronavirus, SARS-CoV-2 (Gorbalenya et al., 2020) , emerged in Wuhan, China and following Figure 1 shows the virion structure of SARS-CoV/SARS-CoV-2. The 25-32 kb genome of 106 SARS-CoV-2 is organized in two large open reading frames (ORF1a and ORF1b, located at the 5' 107 end) coding for replicase polyproteins, followed, in the terminal one-third of the genome, by a 108 region encoding for the structural proteins (spike, envelope, membrane, and nucleocapsid protein). 109 Figure 2 shows the linear ssRNA(+) genome of SARS-CoV2.

As for other respiratory HCoV, the main vehicle of transmission of SARA-CoV-2 are droplets 111 generated by breathing, sneezing, coughing, etc., and contact (direct contact with an infected subject 112 or indirect contact, trough hand-mediated transfer of the virus from contaminated fomites to the 113 mouth, nose, or eyes). In the rapidly evolving picture of the scientific knowledge on COVID-19 and 114 SARS-CoV-2, some studies have reported the presence fragments of viral RNA in faeces or anal 115 swab of infected patients (Holshue et al., 2020; Xiao et al., 2020) . Transmission of COVID-19 116 through the fecal-oral route, however, has not been demonstrated, nor occurrence of SARS-CoV-2 117 in water environments has been proved to date. Information on the presence, quantitative levels, and 118 survival in water environments of coronaviruses of interest for human health are, indeed, limited, and few studies approached development and optimization of methods to concentrate CoV or other 120 enveloped viruses from wastewater, biosolids, surface waters or other water types (see Table 3 ).

The present review summarizes the current state of knowledge on coronaviruses of interest for 122 human health in water environments, with an emphasis on their occurrence and persistence, and on Table 1 ).

A total of 4382 articles were retrieved by the search and duplicates (n=776) were automatically 137 removed using the EndNote Reference Manager software online. Using the Rayyan Review 138 platform (https://rayyan.qcri.org/welcome), titles and abstracts of the retained 3606 articles were 139 screened and assessed for eligibility by two independent reviewers (GLR and ES) and the 140 disagreements were resolved by discussion between the reviewers and a third referee (LB). Based 141 on the objective of the study 3543 records were eliminated as not relevant. Full text screening was 142 undertaken on the retained 63 articles and further 51 articles were excluded as either i) unrelated to 143 CoV in water environments, ii) records duplicating results retrieved by earlier articles (linked 144 articles), iii) articles related only to inactivation of surrogate viruses other than CoV, iv) reviews not including data relevant to the study, v) non-relevant erratum. For one of the 63 retained records, full 146 text was not available for screening but the article was assessed as relevant based on abstract 147 content.

Finally, 12 articles were included in the study, corresponding to original studies whose main 149 findings are presented in Tables 2-4 (Abd- Elmaksoud et al., 2014; Alexyuk et al., 2017; Bibby et al., 150 2011; Bibby & Peccia, 2013; Blanco et al., 2019; Casanova et al., 2009; Collomb et al., 1986; Gundy 151 et al., 2019; Wang et al., 2005a; Wang et al., 2005b; Wang et al., 2005c; Ye et al., 2016) . The twelve retrieved records were divided according to their content in studies related to the 157 investigation of CoV persistence and survival in water environments (n = 4, Table 2 ), occurrence of 158 CoV, pathogenic or potentially pathogenic to humans, in water environments (n = 5, Table 3 ), and 159 analytical methods for concentration of CoV from water (n = 5, Table 4 ). The flow chart of the 160 systematic literature review is illustrated in Figure 3 . (Wang et al., 2005a; Casanova et al., 2009; Gundy et al., 2009; Ye et al., 2016) . 167 Wang and coworkers studied the persistence of SARS-CoV in water (hospital wastewater, domestic 168 sewage and dechlorinated tap water) and in feces and urine (Wang et al., 2005a) . In the study, the 169 effect of sodium hypochlorite and chlorine dioxide in inactivating SARS-CoV, Escherichia coli and 170 the Enterobacteria phage f2 spiked in wastewater was evaluated.

SARS-CoV was detected in hospital wastewater, domestic sewage, and tap water for 2 days at 20°C 172 and up to 14 days at 4°C, thus demonstrating temperature strongly influences viral persistence.

Indeed, it has been universally demonstrated that higher temperatures are associated with rapid 174 inactivation of enteric viruses, and temperature is recognized as the most influential factor for viral 175 survival in water due to increased denaturation of proteins and activity of extracellular enzymes 176 (Pinon and Vialette, 2018) . 177 Wang and coworkers (Wang et al., 2005a) highlighted that SARS-CoV persists 3 days in stools and 178 17 days in urine stored at 20°C. On the other hand, at a lower temperature (4°C) they persist for 17 179 days. The same study showed that chlorine was more effective than chlorine dioxide in inactivating for drinking-water quality, viruses are generally more resistant to free chlorine than bacteria 187 (specifically, "moderate" resistance for viruses, and "low" for the vast majority of bacteria) (WHO, 188 2017). The viruses considered of concern for water in WHO Guidelines, however, are principally 189 enteric viruses (familes Adenoviridae, Astroviridae, Caliciviridae, Hepeviridae, Picornaviridae, and 190 Reoviridae) which are, as previously reported, non-enveloped viruses. It is well known that these 191 viruses are more resistant to environmental conditions, water treatments and disinfectants than 192 enveloped viruses like coronavirus, as lysis of the viral envelope leads to the loss of functional 193 receptors required for infection of susceptible cells (Wigginton et al., 2015) . According to the 194 results of Wang (2005a) , SARS-CoV resistance to chlorine is lower than for bacteria. It follows that 195 the current water disinfection practices (drinking water, wastewater, water from swimming pool), effective against non-enveloped viruses and bacteria, are expected to be effective also towards 197 enveloped viruses such as coronaviruses.

The study of Casanova et al., 2009 (PV-1, Sabin attenuated strain LSc-2ab). In wastewater, the tested CoV died off quite rapidly, with 220 a T 99.9 of 2.77-3.54 days at 23°C. Significantly, the PV-1 lasted 2 to 3 times longer than CoV did, 221 requiring 10.9 days for a comparable reduction in primary wastewater and 5.7 days in secondary effluents. In tap water, CoV reduction was slower than in wastewaters: at 23 °C, the T 99.9 was 12.1-223 12.5 days for HCoV-229E and FIPV, while at 4°C the same reduction was predicted (by modelling) 224 to be achivable over 100 days. These yields highlight once again that virus survival decreases with 225 increasing temperature. Similarly to the results obtained on wastewater, PV-1 survived six times 226 longer than CoV in both filtered and unfiltered tap water, confirming the observation that non-227 enveloped viruses display higher resistance in water enviroments compared to enveloped viruses.

Another important finding of the study was that CoV inactivation was faster in filtered tap water 229 than unfiltered tap water, suggesting that suspended solids in water can provide protection for 230 viruses adsorbed to these particles.

Finally, a more recent study (Ye et al., 2016) 250 Two reports specifically addressing detection in water environments of CoV of interest for human 251 health and three metagenomic/virome studies were retrieved through literature search (Table 3) . Three metagenomic studies have detected CoV in water matrices: two focused on class B biosolids 268 from wastewater treatment facility (Bibby et al., 2011; Bibby& Peccia, 2013) , and one on different 269 type of water (river, lake, reservoir) (Alexyuk et al., 2017) . The study of Bibby and coworkers (Bibby et al., 2011) . In detail, 10 CoV 274 sequences were identified, nine of which related to HCoV-229E and one to HCoV-HKU1.

Two years later, another paper from the same authors described the diversity of viruses in sewage Five studies (Table 4 ) investigated concentration methods for CoV in waters and the associated 296 recovery efficiency.

The first study investigating CoV recovery from waters was published more than 30 years ago 298 (Collomb et al., 1986) using, for the spiking experiments, a bovine enteric coronavirus, and assessing a concentration procedure based on viral adsorption on glass-powder at acid pH followed 300 by alkaline-pH elution. Since CoV is sensitive to acid (pH 3) and alkaline pH (pH ≥ 10), adsorption 301 was optimal at pH 3.3 and elution at pH 9. Under such conditions, the overall efficiency of the 302 concentration method appeared to be between 24% and 28%. Unfortunately, since it was not 303 possible to retrieve the full text of this publication, no further information, beside those included in 304 the abstract, could be reported. significantly higher (from 33.6% to more than 100%). This method therefore seemed more suitable 315 for the concentration of enveloped viruses, in agreement with the initial study proposing its use, that 316 showed recoveries of enterovirus and hepatitis A virus from tap water ranging from 88.7% to 96.0% 317 (Li et al., 1998) . 318 Ye and colleagues (2016) evaluated three methods for separating and concentrating viruses from the 319 liquid fraction of municipal wastewater: i) PEG precipitation, ii) ultracentrifugation, iii) 320 ultrafiltration with centrifugal devices (Ye et al. 2016) . Wastewater (250 ml for PEG precipitation 321 and ultrafiltration and 60 ml for ultracentrifugation) was spiked with the rodent coronavirus Murine 322 Hepatitis Virus (MHV) and with the non-enveloped phage MS2. Low mean recoveries (~5%) were 323 achieved for both MHV and MS2 with the ultracentrifugation method. This result was suggested to 324 be related to virus inactivation by the high g-force of the ultracentrifugation. Recovery of MHV was low (~5%) also with the PEG precipitation method, whose performance for MS2 concentration was interpretation of these comparative results since the quantity of pathogens used for spiking varied for the different microorganisms, precluding a clear differentiation of the effects on recovery 353 efficiency of seeding quantities and pathogen type. HAV, respectively. Similarly, increasing PEG concentration from 10 to 20% in the secondary 372 concentration, showed a significant improvement of the recovery (51.3% and 47.2% for TGEV and 373 HAV, respectively). Following optimization of the method, the procedure provided a recovery 374 efficiency of 5.1 % for TGEV and 4.5% for HAV in spiked surface water. Overall, the study by non-enveloped viruses need adaptation to yield satisfactory performances on enveloped viruses like 377 CoV.

To summarize, this scoping review has highlighted several aspects of coronavirus research that need 380 to be explored in depth. The evidence-based knowledge here reported can be a key support for risk analysis in natural water 399 resources and integrated water cycle, according to the water and sanitation safety planning approaches, as well as for the management and control of water-related risks during the pandemic 401 COVID-19 caused by Further researches are needed to study the potential presence and fate of coronavirus and other 403 enveloped viruses in municipal wastewater and drinking water and to develop robust methods for 404 water analysis.

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Coronavirus OR "Human Coronavirus" OR "Middle East Respiratory Syndrome Coronavirus" OR "Human Coronavirus NL63" OR "Porcine Respiratory Coronavirus" OR "Human Coronavirus OC43" OR "Human Coronavirus 229E" OR "Coronavirus Infections" OR "Rat Coronavirus" OR "Canine Coronavirus" OR "Bovine Coronavirus" OR "Feline Coronavirus" OR "Turkey Coronavirus" OR "Severe acute respiratory syndrome" OR "SARS Virus" OR "COVID-19" OR HCoV OR 229E OR OC43 OR NL63 OR HKU1 OR SARS OR MERS OR 2019-nCoV OR HCoV-229E OR HCoV-OC43 OR HCoV-NL63 OR HCoV-HKU1 OR SARS-CoV OR SARS-CoV-2 OR MERS-CoV #2 Water environments Water OR "Waste Water" OR Sewage OR Wastewater OR River OR "Surface water" OR Groundwater OR "brackish water" OR Seawater OR "sea water" OR "wastewater treatment plant" OR influent OR effluent OR "drinking water" OR "tap water" OR "potable water" OR lake OR "fresh water" OR freshwater OR "marine water" #3 #1 AND #2 • Reagent-grade water • Lake water • Pasteurized settled human sewage• In reagent-grade water at 25 °C, TGEV and MHV were reduced by 99.9% after 33 days and 26 days, respectively (decline of ~0.6 log 10 /week for TGEV and ~0.8 log 10 /week for MHV) • In reagent-grade water at 4 °C, neither TGEV or MHV were significant reduced after 49 days • In lake water at 25 °C, TGEV and MHV were reduced by 99.9% after 13 days and 10 days, respectively • In lake water at 4 °C, TGEV declined by ~1 log 10 in 14 days and MHV did not decline significantly in the same time • In pasteurized sewage at 25 °C, TGEV and MHV were reduced by 99.9% after 14 days and 10 days, respectively (decline of ~1.5 log 10 /week for TGEV and ~2 log 10 /week for MHV) • In pasteurized sewage at 4 °C, a 99.9% reduction was predicted after 73 days and 105 days for TGEV and MHV, respectively (decline of ~0.3 log 10 /week for TGEV and ~0.2 log 10 /week for MHV) Gundy et al., 2009 • Note: For comparison purposes, other microorganisms detected in the studies were reported under 'benchmark' * Metagenomic study ** Solid residuals by primary sedimentation and secondary activated sludge clarification, treated by mesophilic anaerobic digestion, and partially dewatered by belt pressing *** Influent and effluent sludge from mesophilic anaerobic digesters from domestic wastewater treatment plants. Influent samples were mixtures of primary and secondary sludge; effluent samples were of a class B product, prior to dewatering Adsorption-elution-PEG precipitation: adsorption on positive charged filter media particle (silica gel plus Al(OH) 3 ), elution with neutral buffer, PEG precipitation 100 ml • SARS-CoV recovery was 0% and 1.0% in two samples of (sewage from a housing estate) • SARS-CoV recovery was 21.4% in a sample of (sewage from the hospital • SARS-CoV average recovery was 1.02%.

Enterobacteria phage f2 (non-enveloped)• Phage f2 recovery ranged from 33.6 to more than 100% • TGEV recoveries from 5 L of water and elution with glycine/beef extract buffer at: -pH 9.5, 10 min of contact: 2.6% -pH 11.0, 10 min of contact: 28.8% -pH 11.0, overnight: 37.4% -pH 11.0 + Tween 80 0.3%, overnight: 100%• TGEV recoveries from 50 L of water and elution with glycine/beef extract buffer at pH 11.0: -Overnight: 2.9% -Tween 80, overnight: 0.4% -Agitation, overnight: 10.4% -Recirculation, 20 min: 18.0% -Recirculation, 20 min + precipitation with 20% PEG: 51.3%• TGEV recovery from 50 L of water with the optimized protocol: 5.1 ± 1.4%

Hepatitis A virus, strain HM175 43c• HAV recovery from 50 L of water with the optimized protocol: 4.5 ± 1.5%Note: For comparison purposes, other microorganisms used in the experimental plans were reported under 'benchmark' *the full text of this paper was not recovered, therefore information was retrieved from the abstract

• SARS Coronavirus has been detected in wastewater but not as infectious particles • Temperature is an important environmental factor affecting CoV survival in water • CoV show limited environmental stability and sensitivity to oxidants as chlorine • There is no evidence of CoV transmission through contaminated water • Methods for CoV concentration from waters should be optimized

☒ 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:Giuseppina La Rosa