Across the world, researchers and scientists are devising methods to test as many people as possible, even the asymptomatic ones at this point since many countries are exhibiting community spread of the coronavirus. And while protocols such as surveillance (like in China, Singapore or India) or aggressive testing (like that in South Korea) have brought in some positive results, there’s another method that some experts are opening up to as a potential way to track the virus. Sewage surveillance, or essentially testing poop and wastewater to detect the virus, is a protocol that countries like the United States, the Netherlands and Sweden have tried during the outbreak. And now, a group of multi-disciplinary experts in India are developing protocols to test it out in select urban pockets in India.
Sewage surveillance is being seen as one of the methods to detect early warning signs of the pneumonia-causing virus, especially because previous studies have shown viral shedding in fecal samples from coronavirus patients, some even within three days of the infection that takes up to two weeks to get severe. In the past, wastewater testing has been used to detect viruses such as polio and measles, along with illicit drugs, tobacco and alcohol.
And even though infection-control measures such as social distancing and lockdowns are more popular, studies say that the virus could return once such protocols are lifted, or even despite them. So while the sewage is an unlikely route of transmission of the virus, its monitoring can allow experts to detect mild to no symptoms on those not tested yet.
The initiative, called COVID Action Collab (CAC), launched by Indian social enterprise Catalyst Group, has brought together around 150 individuals and organisations from across the country to tackle the pandemic, and includes microbiologists, virologists, sanitation workers, public health communities and organisations like National Urban Affairs. Even as the group works on developing a method to collect and test samples in India in a way that helps identify traces in localities, the surveillance method will be adapted from countries like Europe, the US and Australia where such testing has taken place and yielded positive results.
In fact, in India, experts are looking at it with much promise considering the densely populated pockets make it challenging for large-scale testing—especially in the light of insufficient testing kits. This “non-invasive” early-warning tool, says the group, could also be used to test factory clusters in neighbourhoods, especially since the Indian government is currently mulling over reopening the economy (which includes factories among other infrastructure) to restore India’s broken supply chain.
“By mapping collection areas, it will be possible to narrow down where people infected with the virus live and follow it up with identification through clinical tests, quarantine and treatment measures,” said Dr Angela Chaudhuri, a health strategy partner with the Catalyst Group who has worked in public health sector for over 19 years, in a press statement. Tracking virus strains in wastewater will also give a head start to public health officials on what kind of measures they have to introduce to contain the spread of the virus.
At the moment, the CAC is working on developing a testing method for urban residential areas and factory clusters in Kolkata and Bengaluru. “COVID-19 isn't going away anytime soon,” said Chaudhuri. “Before we move into another lockdown, it is imperative that we continue community monitoring, especially in densely populated areas, to serve as an early warning system.”
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