Sewage surveillance for the presence of SARS-CoV-2 genome as a useful wastewater based epidemiology (WBE) tracking tool in India

Abstract

The infection with SARS-CoV-2 is reported to be accompanied by the shedding of the virus in stool samples of infected patients. Earlier reports have suggested that COVID-19 agents can be present in the fecal and sewage samples and thus it can be a good indication of the pandemic extent in a community. However, no such studies have been reported in the Indian context so far. Since, several factors like local population physiology, the climatic conditions, sewage composition, and processing of samples could possibly affect the detection of the viral genome, it becomes absolutely necessary to check for the presence of the SARS-CoV-2 in the wastewater samples from wastewater treatment plants (WWTPs) serving different localities of Jaipur city, which has been under red zone (pandemic hotspots) since early April 2020. Samples from different local municipal WWTPs and hospital wastewater samples were collected and wastewater based epidemiology (WBE) studies for the presence of SARS-CoV-2 were carried out using the RT-PCR technique to confirm the presence of different COVID-19 target genes namely S gene, E gene, ORF1ab gene, RdRp gene and N gene in the viral load of wastewater samples. In the present study, the untreated wastewater samples from the municipal WWTPs and hospital wastewater samples showed the presence of SARS-CoV-2 viral genome, which was correlated with the increased number of COVID-19 positive patients from the concerned areas, as per reported in the publically available health data. This is the first study that investigated the presence of SARS-CoV-2 viral genome in wastewater, at higher ambient temperature (above 40°C), further validating WBE as a potential tool in predicting and mitigating outbreaks.