Chennai Metrowater has detected the presence of COVID-19 RNA in sewage samples collected in Chennai as part of a preliminary study.
For the study, sewage samples were randomly collected from five sewage pumping stations across the city and were analysed for the presence of the COVID-19 viral RNA. The samples were tested through the RT-PCR technique at two accredited labs.
According to sources, the presence of the COVID-19 viral RNA was detected in two samples and a correlation of confirmed cases was also established in the locations from where samples were lifted.
“However, studies across the world show that detection of virus in sewage is not an indication that the virus may be infectious. COVID-19 transmission does not occur through sewage. The process of sewage treatment, including chlorination, kills the virus,” according to a source. Metrowater partnered with World Health Organisation India to devise a study and evolve guidelines for control of COVID-19 through wastewater surveillance. Sources said it could probably be the first time in the country where COVID-19 RNA has been successfully detected in sewage.
In case of asymptomatic infections, it would come in handy to identify COVID-19 carriers in an area and help step up screening and other intervention measures.
Citing studies in many countries, including Netherlands, sources said the disease could be identified in faeces within three days of infection. The wastewater-based epidemiology approach would help alert a population cluster that is covered by a specific sewage treatment plant. Regular monitoring of wastewater even after the disease subsides would serve as an indicator to determine whether the pandemic has been brought under control.
