Coronavirus: Singapore is now checking waste water with people’s poo for virus
Singapore wants to test raw sewage for traces of COVID-19 to monitor community transmission especially among people who are infected but do not yet know it.
After implementing several methods to stem the spread of the novel coronavirus, ranging from mass testing thousands of its migrant workers to using serological tests to uncover links between its coronavirus clusters, Singapore is now testing sewage for traces of COVID-19.
This comes as the city state, with 38,965 infections and 25 deaths, last week lifted parts of its partial lockdown but the authorities say that the easing of its measures would be gradual amid fears of a second wave of infections.
The city state is now testing waste water extracted from manholes for viral fragments, said National Development Minister Lawrence Wong, who co-heads a multi-ministerial task force that deals with the virus.
“This provides an additional indicator to tell us if a specific group, such as those living in a dormitory, has infected people among them,” he said during a national address.
Officials in Singapore have attributed the dramatic rise in coronavirus cases to the aggressive testing of low-wage migrant workers in cramped dormitories, who now make up more than 93 per cent of its total infections. Many Indians live in dormitories for foreign workers.
Leong Hoe Nam, an infectious diseases expert in Singapore, was cited by the South China Morning Post as saying that waste testing made use of a “peculiar habit” of the coronavirus, which is that it is shed in stools.
“The value of it is that it identifies groups of people infected but not yet presented to the emergency department meaning you could potentially predict new clusters,” he added.
But the expert says that there are restrictions to the method. For example, if faecal matter extracted from a particular sewer tested positive for the virus, this could mean that hundreds of residents living in that area could have the virus.
“We can notify doctors and hospitals to be on alert and send reminders. But ultimately, finding that individual is like finding a needle in a haystack,” said Leong.
This testing of raw sewage has been done earlier too. Australia in May said it intended to roll out a vast programme of raw sewage testing for virus traces in waste water and excrement, so it could focus testing and tracing on problem neighbourhoods.