January 09 2021 at 03:49 PM by Samikshya Joshi
Easiest method to monitor Covid-19
Researchers have come up with a plan to monitor the viral load at the sewage treatment plants every week as an early warning system to detect any second wave of Covid-19 infections. This, in the light of a new strain of the virus emerging, can help authorities conduct focused testing and isolation based on where the viral load is detected instead of quarantining the entire city, they said in a study. The viral load in sewage can help researchers calculate the number of Covid cases and identify hotspots. "The viral load was negative in samples from outlets at the plants indicating that a treatment process which includes chlorination can completely remove SARS-CoV-2 in treated water," said Paromita Chakraborty, project leader and associate professor from SRM Institute of Science and Technology. This proved the city residents were being supplied clean treated water, she said. A semi-quantitative analysis of the viral load in each catchment area can help estimate the predicted number of infected people in a particular area. "This is a cost-effective method that can help predict the number of Covid-19 cases in a catchment without testing a large population. If the catchment area population is five lakh for the treatment plant, we can calculate the number of positive cases if we know the number of RNA copies (viral particles) in sewage by using a mathematical calculation. Australia, France and Spain monitor sewage to know the spread of the virus, but there is no such surveillance in countries like India, she said. Ten-fold higher RNA copies were observed in Cooum over Adyar. It may be due to poor sanitation conditions." The study found that Perungudi, with a population of about 30 lakh, had one-fourth of SARS-CoV2 predicted cases compared to Koyambedu and Kodungaiyur as the RNA copies were fewer in comparison.