Covid warning signs in Pune: All 10 sewage plants show presence of virus, indicating community spread

Time of India

2 days ago

Gradual rise mirrors previous trends
Retrospective analysis prompted by global reports
Live Events
Sewage testing offers early warning
Variant identification remains difficult
Shared with health authorities for preparedness
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The CSIR-National Chemical Laboratory (NCL) in Pune has confirmed the presence of SARS-CoV-2 genetic material in wastewater samples collected from all 10 sewage treatment plants (STPs) in the city. The first positive sample was detected on April 22, with all plants testing positive from May 6. Dr Mahesh S. Dharne, scientist and microbiologist at NCL, told, 'The first sample turned positive on April 22 from one of the STPs. From May 6 onwards, all STPs are showing positive results for SARS-CoV-2 via RT-PCR.'Dr Dharne said the recent rise in viral presence appears gradual, but it resembles patterns observed before earlier Covid-19 waves. 'What we are observing now is that the viral load patterns are similar to those threshold levels we have seen before surges picked up momentum. This gives us a better opportunity to track trends as they develop,' he said.He added, 'The positive samples from April 22 onwards confirmed the virus's presence, though heavy rainfall last month may have diluted the viral load, making it challenging to assess the true extent of the rise. The rain likely affected our samples. But with clearer weather now, this week's data, expected by Friday or Saturday, will provide a clearer picture.'The current findings came after a retrospective analysis was triggered by reports of rising Covid-19 cases in Singapore and other countries. 'We were collecting samples and storing them. But when we saw news from Singapore, we decided to analyse what the scenario was in Pune,' Dr Dharne said.Out of approximately 60 weekly samples tested from the 10 STPs, about 40 have returned positive results.Wastewater surveillance is being used as an early indicator of community spread. It detects viral material shed by infected individuals, including those who do not show symptoms or have not been tested. Unlike clinical testing, it captures the viral presence of entire populations connected to a sewage system.NCL is the only institute systematically monitoring all 10 sewage plants in Pune. It has previously helped track surges related to Omicron and its sub-lineages.While the presence of the virus can be detected through RT-PCR, identifying specific variants remains a challenge. 'RT-PCR helps us detect viral presence and estimate load, but pinpointing the exact variant is difficult,' Dr Dharne said.NCL shares the wastewater surveillance data weekly with the Integrated Disease Surveillance Programme (IDSP), the Maharashtra state Covid task force, and the National Centre for Disease Control (NCDC), New Delhi.This surveillance work is part of the Four City Surveillance Programme, supported by the Rockefeller Foundation since August 2021. The programme also covers Hyderabad, Bengaluru, and Sonipat. Partner institutions include CSIR-Centre for Cellular and Molecular Biology (CCMB), Tata Institute for Genetics and Society's National Centre for Biological Sciences (TIGS-NCBS), Ashoka University, and Pune Knowledge Cluster.The programme is mentored by Dr Rakesh Mishra (TIGS), Dr L.S. Shashidhara (NCBS), and Dr Vinay Nandikoori (CCMB).