The country's premier scientific body, Council of Scientific and Industrial Research (CSIR), has recommended setting up sewage and air surveillance systems in Parliament to detect the prevalence of Covid-19 to estimate the number of people infected in a population to be used to understand the progression of infection even when mass scale tests for individuals are not possible.
A presentation in this regard was made on Tuesday before Vice President M Venkaiah Naidu who, being the chairperson of Rajya Sabha, said he would discuss the issue with Lok Sabha Speaker Om Birla and the government.
Elaborating on the relevance of sewage surveillance in his presentation, Director General of CSIR Shekhar C Mande said, "Covid-19 patients shed SAR-CoV-2 in stools. Apart from symptomatic individuals, asymptomatic people also shed the virus in their stools."
Sewage surveillance provides a qualitative as well as a quantitative estimate of the number of people infected in a population and could be used to understand the progression of Covid-19 even when mass scale tests for individuals are not possible, an official statement said quoting the CSIR chief.
It is a measure to comprehensively monitor the prevalence of the disease in communities in real time, Mande said.
Presenting data of sewage surveillance carried out to find the trend of infection in Hyderabad, Allahabad, Delhi, Kolkata, Mumbai, Nagpur, Puducherry and Chennai, he said it provides an unbiased estimate of numbers since the sampling is not done at the individual level.
Mande said that sewage surveillance of Covid-19 would not only help understand the present epidemiology of the disease but would be an indispensable tool for early and easier detection of future coronavirus outbreaks.
However, the Central Pollution Control Board (CPCB) has already asked sewage water treatment plants to ensure adopting all covid-19 precautions for its workers to protect them from SARS CoV2 infection as virus found in sewage water may be a source of transmission of disease.
“We are already conducting surveillance of SARS CoV2 virus in biomedical waste and wastewater. We have recently observed that viral RNA is found in sewage water and there is a high possibility in biomedical waste too.
“However, currently there is no evidence that virus transmission occurs through sewage, but if that is, which we still may not know, the workers in the sewage treatment plants may be highly susceptible to the infection," said T K Joshi, member, Central Pollution Control Board (CPCB) task force on air pollution and health.
, we have asked the sewage treatment plants to provide all preventive gear to the workers ranging from Personal Protective Equipment (PPE) kits, coveralls, gloves and face shields to protect them from covid-19," said T K Joshi, member, Central Pollution Control Board (CPCB) task force on air pollution and health.
At the global level too, there has been various research in this regard. For instance, researchers from the University of California San Diego have carried out a study to describe a mostly automated early alert system that helps in identifying buildings where new Covid-19 cases have emerged--even before infected people develop symptoms.
The research was published in the mSystems, an open-access Journal of the American Society for Microbiology, “This approach is fast, cost-effective, and sensitive enough to detect a single case of COVID-19 in a building that houses nearly 500 people,” said UC San Diego environmental engineer and first author Smruthi Karthikeyan.
"It really lets us get a handle on new outbreaks before they get worse," she said.
Earlier studies have also demonstrated that analysing viral concentrations in sewage can accurately predict trends in clinical diagnoses up to a week in advance.
