Quirks & Quarks

The key to early detection of COVID-19 outbreaks might be in sewage

'We may actually start seeing genetic signals of the virus up to a week prior to its manifestation within the community.'

Testing sewage water could give public health officials a week's advance notice of potential outbreaks

Scientists think they can use sewage water to get an early indication of COVID-19 spread.  (Shutterstock / Bangkoker)
Listen7:22

One of the things standing in our way of getting a handle on COVID-19 is our inability to track the virus' spread in real time. 

If you become infected, it takes about four or five days before your symptoms appear, by which time you're already infectious and can spread the virus to any number of people before you even get an inkling you're sick. So by the time you get tested and get your results back, we're losing valuable time in our efforts to track, trace and contain the viral spread.

This is why scientists from around the world, including right here in Canada, are so keen about the potential for using sewage water as an early indicator for emerging community outbreaks.

"We may actually start seeing genetic signals of the virus up to a week prior to its manifestation within the community," said Mike Mckay, the executive director of the Great Lakes Institute for Environmental Research at the University of Windsor.

He is running a pilot project, one of many being rolled out across the country, to test how effective sewage water surveillance can be as an early biomonitoring tool. 

Mckay told Quirks & Quarks host Bob McDonald that previous research had shown that this way of monitoring COVID-19 in the community could detect "as few as one infected person in a population of 100,000,"  so it's very sensitive.  But at the moment it can only really be used to show whether the virus is present or absent. This means this type of surveillance would be best to use to keep an eye on broad trends - a way to test whole communities for the virus, rather than individuals.

"I think right now, the scientists who are involved in this research are looking at it more — not in terms of extrapolating to determine how many people in the community are infected, but to use this approach to sense or provide early warning of re-emergence or changes in trends of infection the community."

If the pilot research projects being coordinated by the Canadian Water Network prove helpful in our efforts to contain the early spread of COVID-19, Mckay said he hopes different levels of government recognize the potential benefit of such a surveillance network.

"We would love to see this being picked up by our provincial governments or the federal government as a provincial or national public health strategy," added Mckay.

Written and produced by Sonya Buyting

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