SARS-CoV-2 Detection in Sewage in Santiago, Chile - Preliminary results

Abstract

<jats:p>The detection of viruses in sewage is a method of environmental surveillance, which allows evaluating the circulation of different viruses in a community. This study presents the first results of sewage surveillance to detect the circulation of SARS-CoV-2 virus in Santiago, Chile. Using ultracentrifugation associated with RT-qPCR, we detected SARS-CoV-2 in untreated and treated wastewater samples obtained two treatment plants, which together process around 85% of the wastewater from the city. This is the first report of detection of SARS-CoV-2 in sewage in Chile and indicates that wastewater surveillance could be a sensitive tool useful as a predictive marker of the circulation of the virus in a population and therefore, be used as an early warning tool.</jats:p>

A review on presence, survival, disinfection/removal methods of coronavirus in wastewater and progress of wastewater-based epidemiology

“…Although there is a lack of studies on the presence of SARS-CoV-2 in wastewater, the detection of viral RNA (ribonucleic acid) in wastewater samples has gained considerable attention based on the idea of wastewater-based surveillance to detect community spread. As per the aim and scope of the present study, 34 works (eight research articles ( Table 1 ) and 26 pre-print articles [ [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] ]) are included to understand the applicability of wastewater-based surveillance.…”

“…They also observed that quantified RNA concentration was correlated (when adjusted for time lag) with the epidemiological curve (R 2 value of 0.99) and the number of admissions in local hospital (R 2 values of 0.99). Ampuero et al [ 20 ] attempted to detect the circulation of SARS-CoV-2 by sewage surveillance of two WWTPs serving 85 % of the wastewater generated in Santiago, Chile. When the cases of COVID-19 were low, SARS-CoV-2 RNA was not detected in wastewater.…”

“…The studies related to coronavirus in wastewater and application of WBE for detection of infection, if any and also scale of infection within a community have highlighted several issues which requires special attention for successful implementation of WBE. The issues are explained point wise as (a) the several methods currently being used for SARS-CoV-2 detection produce inconsistent results (for example, positive result by one method and negative by another) [ 13 ], (b) variability in results were observed when grab and composite samples were compared, two investigations [ 31 , 38 ] suggested composite sampling technique to provide more reliable data, (c) although wastewater samples are collected in majority of the WBE related investigations, the study conducted by Balboa et al [ 37 ] suggested WWTP sludge as more suitable due to the affinity of enveloped viruses towards solids, (d) the finding of no detection of SARS-CoV-2 due to low number of COVID-19 cases [ 20 ] expresses the necessity of research for finding detection limit and factors affecting detection limit, study conducted by Hata et al [ 36 ] can provide some light in this regard, (e) although several investigations reported correlation being observed between SARS-CoV-2 in wastewater/sludge with confirmed COVID-19 cases, few reported lack of correlation [ 24 , 26 ]. Above all, WBE has the potential to detect infection within a community ahead of the onset of symptoms in COVID-19 positive individuals and even in case of asymptomatic individuals.…”

Where do we stand to oversee the coronaviruses in aqueous and aerosol environment? Characteristics of transmission and possible curb strategies

“…The conventional wastewater treatment process (normally the activated sludge process) should be good enough to inactivate SARS-CoV-2. In contrast, some studies reported that the positive results for viral RNA in effluent could still be discovered even after WWTP treatment [25] , [44] . The possible reasons to explain these contradictory results are the lack of a standardized procedure of SARS-CoV-2 RNA detection in wastewater, and the various treatment techniques adopted in different WWTPs at reality environmental conditions.…”

“…Recently, large numbers of investigations have reported that the RNA of SARS-CoV-2 has been detected in raw sewage, secondary treated wastewater (normally biological wastewater treatment process being applied), and even the non-potable water used for urban irrigation ( Fig. 2 ) [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] . More importantly, the infectious virus has also been detected in feces and urine of patients [45] , [46] , [47] , which triggered the public’s high concern about fecal-oral transmission and/or wastewater transmission.…”