COVID-19's so-called "poop signal" alerts health officials through sewage surveillance

CTVnews.ca
June 28, 2021

After nasal testing, the number two source of data in the COVID-19 outbreak -- testing wastewater -- is showing some movement, with more people in Ontario getting access to the raw data for the first time.

York Region has joined a growing number of regions posting the results of a sewage surveillance network -- as some scientists call, a “poop signal” -- that boasts it can warn public health officials of an outbreak before people even get sick.

“Everybody poops. Everybody makes a contribution every day,” Dr. Mark Servos, a biologist at the University of Waterloo, whose lab examines samples that go down the drains in York Region and elsewhere, said.

“There’s a tremendous amount of information in that wastewater.”

Servos’ team reports back its results and usually finds that they correspond to the highs and lows of the parallel patient testing numbers.

With one notable advantage: his information doesn’t depend on who’s getting tested -- a concern about blind spots as some communities find themselves reflected more heavily in the data.

“It doesn’t depend on whether they’re asymptomatic, or vaccinated, or rich or poor or whatever,” Servos said.

What is in the sewer stream has now gone mainstream: Ontario’s government has put $12 million into creating a sewer surveillance network that includes Ottawa, the GTA, Hamilton, London and Windsor. It’s also focused on expanding testing to some First Nations communities and long-term care homes.

At the University of Windsor, Dr. Mike McKay pivoted to testing fecal matter when he realized its potential.

“Everyone who is infected sheds the virus, and we can pick that up in the wastewater stream,” McKay told CTV News.

In late March, his staff found a positive test in the pipes under a residence and called public health right away.

“We had a mobile testing unit on campus the next day that tested students living in the residence hall and detected, and likely averted, a larger outbreak on campus,” McKay said.

He said the network has potential to go beyond COVID-19, by testing for other diseases.

York Region is the first in the Greater Toronto Area to put that testing data online. The City of Toronto says it’s paying attention to the information that scientists are sending, but said it’s not putting it online yet.

“We do have data and I am paying attention to it,” said Dr. Eileen De Villa at a news conference.

“I get regular reports from the team.”

York Region’s figures confirm COVID-19 rates are showing some movement downwards.

Soon, other regions may sign onto the provincial network. After all, all that raw sewage may be a terrible thing to waste.