A critical review on SARS-CoV-2 infectivity in water and wastewater. What do we know?

Abstract

The COVID-19 outbreak circulating the world is far from being controlled, and possible contamination routes are still being studied. There are no confirmed cases yet, but little is known about the infection possibility via contact with sewage or contaminated water as well as with aerosols generated during the pumping and treatment of these aqueous matrices. Therefore, this article presents a literature review on the detection of SARS-CoV-2 in human excreta and its pathways through the sewer system and wastewater treatment plants until it reaches the water bodies, highlighting their occurrence and infectivity in sewage and natural water. Research lines are still indicated, which we believe are important for improving the detection, quantification, and mainly the infectivity analyzes of SARS-CoV-2 and other enveloped viruses in sewage and natural water. In fact, up till now, no case of transmission via contact with sewage or contaminated water has been reported and the few studies conducted with these aqueous matrices have not detected infectious viruses. On the other hand, studies are showing that SARS-CoV-2 can remain viable, i.e., infectious, for up to 4.3 and 6 days in sewage and water, respectively, and that other species of coronavirus may remain viable in these aqueous matrices for more than one year, depending on the sample conditions. These are strong pieces of evidence that the contamination mediated by contact with sewage or contaminated water cannot be ruled out, even because other more resistant and infectious mutations of SARS-CoV-2 may appear.

SARS-CoV-2 exposure in wild white-tailed deer (Odocoileus virginianus)

“…Multiple activities could bring deer into contact with people, including captive cervid operations, field research, conservation work, wildlife tourism, wildlife rehabilitation, supplemental feeding, and hunting (10). Wildlife contact with contaminated water sources has also been offered as a potential transmission route (11), although transmissibility of SARS-CoV-2 from wastewater has yet to be conclusively demonstrated (26). Transmission from fomites or other infected animal species cannot be discounted.…”

Wastewater-Based Epidemiology for Community Monitoring of SARS-CoV-2: Progress and Challenges

“…To date, at least 21 countries have reported the presence of the SARS-CoV-2 RNA in wastewater systems including untreated wastewater, treated wastewater, and sludge ( Table S1 ), but no infectious SARS-CoV-2 has been detected in wastewater and no case of SARS-CoV-2 transmission via contact with sewage or sewage-contaminated water has been reported. 25 , 26 In addition, it has been reported that conventional disinfection of water ensures inactivation of SARS-CoV-2. 27 Several WBE studies have reported the occurrence of local community transmission of SARS-CoV-2 before the first notified clinical SARS-CoV-2 case.…”

Wastewater monitoring as a supplementary surveillance tool for capturing SARS-COV-2 community spread. A case study in two Greek municipalities

“…Our analysis was focused on the relationship between SARS-CoV-2 RNA concentrations and 7-day cumulative cases, although a larger time window would also reflect a plausible scenario. SARS-CoV-2 RNA can enter the sewage system through wastewater discharged from households and other establishments frequently inhabited by active carriers, but also from hospitals and isolation facilities ( Giacobbo et al, 2021 ) and may occur in several forms in wastewater which include at least i) infectious protected, ii) non-infectious protected and iii) non-protected forms ( Wurtzer et al, 2021 ). It has been shown that infected persons have been found to excrete the virus for prolonged periods ( Cevik et al, 2021 , Zhang et al, 2020 ).…”