Canada to test wastewater for polio

Canada plans to start testing sewage in several cities for poliovirus following new reports of cases abroad, the Public Health Agency of Canada confirmed on Friday.

Although Canada has been polio-free since 1994, thanks to the acceptance of the polio vaccine, PHAC warns that it could make a comeback, as it is still circulating in other countries.

New York state confirmed a single case of polio on July 21, and the Associated Press reported Friday that the virus that causes the highly transmissible paralytic disease was detected in New York City sewage.

In a statement emailed to on Friday, the Public Health Agency of Canada said it is aware of the confirmed case in New York and plans to launch a sewage testing initiative in Canada “as soon as possible.” . So far, no recent cases of polio have been detected in Canada.

“PHAC has been reaching out to national and international partners who are experts in this field to finalize a wastewater testing strategy,” the agency wrote, adding that it will also begin testing wastewater samples collected earlier this year from key high-risk communities to determine if polio was present in Canada prior to reported international cases.

“PHAC will also submit samples to the US Centers for Disease Control and Prevention for further confirmation,” the agency wrote. He did not say when or where the tests will take place.


Poliomyelitis is usually asymptomatic, but in some cases, the viral infection can cause paralysis or death.

Since sewage testing can detect the presence of viruses in a community where asymptomatic cases might evade clinical detection, environmental scientist Mike McKay said it could be a valuable tool for public health agencies watching to see if the virus returns. to Canada.

McKay is executive director of the Great Lakes Environmental Research Institute at the University of Windsor. He leads a team that has analyzed wastewater samples from Windsor, Leamington, Amherstburg, Lakeshore, London, Sault Ste. Marie, North Bay and Thunder Bay during the pandemic. While wastewater testing was used to monitor drug use in Canada before the pandemic, it was only with the advent of COVID-19 that scientists like McKay began using it to track the spread of viruses.

“Wastewater has been underutilized, overlooked for so long, and it’s exciting to realize what a potential resource it can be in helping us understand disease transmission through communities,” McKay told in an interview on Friday.

Following the successful use of wastewater tests to track COVID-19, McKay said some of his colleagues at other institutions across Ontario have already started using them to monitor for diseases such as influenza and monkeypox.

“Recognizing its broader application to public health is really exciting, and we’re happy to be able to get involved and help public health units respond to COVID-19 and hopefully future outbreaks,” he said.

However, PHAC cautioned that accurately testing wastewater for poliovirus is an imperfect and developing science. For example, sewage detections can be affected by extreme precipitation events, such as flooding in a community.

The agency said it’s important for children to be fully vaccinated and up to date on their boosters, since countries where the virus isn’t normally found, such as the UK, Israel and USA – report new cases.

“While the overall risk of polio to the Canadian public remains low, these international cases are a good reminder to stay current on vaccinations, including for rare vaccine-preventable diseases,” the agency wrote.

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