The paper, ‘The Spectre of SARS-CoV-2 in the Ambient Urban Natural Water in Ahmedabad and Guwahati: A Tale of Two Cities’, is currently in preprint. It is authored by experts from IIT-Gandhinagar (IIT-Gn), IIT-Guwahati, GBRC, and JNU with Prof Manish Kumar of IIT-Gn as lead author.
The researchers said that 26% of the samples (eight of the 31) were found to be positive (showing virus presence). “A higher SARS-CoV-2 genome concentration was observed in Sabarmati River (492 copies/lakh litres of water), followed by Kankaria (318 copies/L) and Chandola (75 copies/L),” the paper said. “The number of active Covid-19 cases in Ahmedabad on the day of sampling matched the gene amplification and detection patterns (viral genetic load) in surface water rather well.”
Prof Kumar said that they had earlier showed the presence of Covid-19 in wastewater as an efficient way of surveillance. “We started with a question — can the places where wastewater treatment is not happening be included in surveillance,” he said. “Thus, we chose surface water. It can add another layer of surveillance.”
Prof Kumar added that the viruses found from the samples are not ‘live’. “We checked for traces of the virus in a given sample through RNA or genes,” he said. “So far, we have not seen any definitive proof that the virus spreads through water. Thus, citizens need not fear about virus in the water.”
Experts have long stressed on water surveillance as an effective method to predict a spike in cases. One researcher said that even in these lakes, the source largely remains treated water. Thus, the presence can also indicate the way the water is treated.
