Photo: Reuters/Eric Seals
The science of sewage surveillance could be deployed in countries across the world to help monitor the spread of national epidemics of COVID-19 while reducing the need for mass testing, scientists say.
Experts in the field - known as wastewater epidemiology - say that as countries begin to ease pandemic lockdown restrictions, searching sewage for signs of the SARS-CoV-2 coronavirus could help them monitor and respond to flare-ups.
Small early studies conducted by scientific teams in The Netherlands, France, Australia and elsewhere have found signs that the COVID-19-causing virus can be detected in sewage.
“Most people know that you emit lots of this virus through respiratory particles in droplets from the lungs, but what’s less well known is that you actually emit more small virus particles in faeces,” said Davey Jones, a professor of environmental science at Britain’s Bangor University.
This suggests that on a wider scale, sewage sampling would be able to estimate the approximate number of people infected in a geographic area without having to test every person.
“Every time a person becomes infected with COVID-19, they start shedding virus into the sewer system,” Jones said. “We’re using that (knowledge) and tracking people’s toilet movements.”
The practice has been used to monitor health threats and viral diseases before.
It’s a crucial tool in the global fight to eradicate polio, and scientists in Britain and elsewhere also use it to monitor antibiotic resistance genes from livestock farming.
“Wastewater epidemiology has been part of monitoring of polio infection across the world, so it’s not completely new,” said Alex Corbishley, a veterinary scientist at the Roslin Institute in Edinburgh who is running a three-month pilot project to track SARS-CoV-2 in wastewater in Scotland. “But it’s never really been applied to an outbreak in this way.”
“The idea here is that you could potentially use this as a relatively cheap, but much more importantly, scaleable, way of saying ‘there’s X amount of transmission’ in a community.”