Systematic assessment of SARS-CoV-2 virus in wastewater, rivers and drinking water – A catchment-wide appraisal

Abstract

Human coronaviruses (HCoVs) attracted attention in 2002 with the severe acute respiratory syndrome (SARS) outbreak, caused by the SARS-CoV virus (mortality rate 9.6%) and gained further notoriety in 2012 with the Middle East respiratory syndrome (MERS) (mortality rate 34.3%). Currently, the world is experiencing an unprecedented crisis due to the COVID-19 global pandemic, caused by the SARS-CoV-2 virus in 2019 (estimated mortality rate 10%). The virus can pass to the faeces of some patients, as was the case of SARS-CoV and MERS-CoV viruses. This suggests that apart from the airborne (droplets and aerosols) and person-to-person (including fomites) transmission, the faecal–oral route of transmission could also be possible for HCoVs. In this eventuality, natural water bodies could act as a virus reservoir of infection. Here, the temporospatial migration and attenuation of the SARS-CoV-2 virus in municipal wastewater, the receiving environment, and drinking water, is evaluated, using the polymerase chain reaction (PCR), in the South African setting. SARS-CoV-2 viral RNA was identified in raw wastewater influent but was below the detection limit in the latter treatment stages. This suggests that the virus decays from as early as primary treatment and this could be attributed to wastewater's hydraulic retention time (2–4 h), composition, and more importantly temperature (>25 °C). Therefore, the probability of SARS-CoV-2 virus transportation in water catchments, in the eventuality that the virus remains infective in wastewater, appears to be low in the South African setting. Finally, catchment-wide monitoring offers a snapshot of the status of the catchment in relation to contagious viruses and can play a pivotal role in informing the custodians and downstream water users of potential risks embedded in water bodies.

Utilization of SARS-CoV-2 Wastewater Surveillance in Africa—A Rapid Review

“…These articles were imported into Convidence and nine duplicates were removed, leaving 35 articles included in the abstract screening. A total of 23 studies were excluded following abstract screening, leaving 12 articles [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ] for full-text screening. Four articles [ 27 , 28 , 30 , 34 ] were excluded after full-article screening, leaving eight articles for data extraction ( Supplementary Table S1 ).…”

“…Of the eight articles included in the study, four were from South Africa [ 29 , 31 , 33 , 38 ], two from Morocco [ 35 , 36 ], and one each from Cameroon [ 32 ] and Tunisia [ 37 ]. Three were cross-sectional studies [ 29 , 33 , 37 ], four were reviews [ 32 , 35 , 36 , 38 ], and one was a short communication/proof-of-concept piece [ 31 ]. More details are presented in Supplementary Table S1 .…”

“…Of the four studies that collected and analyzed wastewater, three were conducted in South Africa [ 29 , 31 , 33 ] and one in Tunisia [ 37 ]. In all four studies, SARS-CoV-2 was extracted from municipal wastewater.…”

“…In all four studies, SARS-CoV-2 was extracted from municipal wastewater. A study conducted to evaluate the temporospatial migration and attenuation of the SARS-CoV-2 virus using the polymerase chain reaction (PCR) in municipal wastewater in South Africa [ 29 ] utilized the 2019-nCoV genesig ® Advanced Kit (Primerdesign Ltd., Plymouth Meeting, PA, USA). Two other studies conducted in South Africa [ 31 , 33 ] utilized the RT-PCR (Whitehead Scientific, Integrated DNA Technologies, AI, USA) extraction methodology.…”

“…In Tunisia, Jmii et al [ 37 ] used the Allplex 2019-nCoV kit (Seegene, Seoul, Korea) and the QuantiTect virus Kit (Qiagen, Hilden, Germany) for extraction. Of the three cross-sectional studies, two targeted the RNA-dependent RNA polymerase (RdRp) gene [ 29 , 37 ].…”