Alberta can now track the prevalence of COVID-19 infections in nearly 75 per cent of the population thanks to the new Pan-Alberta Network for Wastewater-based SARS-CoV-2 Monitoring announced today.
When someone is infected with COVID-19 — whether they know it or not — traces of the virus are shed through the bowel and end up getting flushed down the toilet.
A team of researchers from the University of Calgary will monitor eight sewage treatment plants and pump stations covering 10 cities and towns including Fort McMurray, Airdrie, Canmore, Calgary, and Okotoks. The University of Alberta’s team from the Faculty of Medicine & Dentistry will track at nine locations covering 15 municipalities including Grande Prairie, Cold Lake, Fort Saskatchewan, Edmonton, Red Deer, Banff, High River, Medicine Hat and Lethbridge. It is hoped more municipalities will join as the project expands.
Samples will be taken three times a week and the results shared on a public website.
‘We already have 17 months of data to show how the wastewater testing correlated with community infection, so it is a useful surveillance tool,” said U of A co-lead Xiaoli Lilly Pang, a professor of laboratory medicine and pathology who received a Canadian Institutes of Health Research COVID-19 rapid research grant for Alberta municipal wastewater testing in June 2020.
“By merging the two teams (from U of C and U of A) we will enhance our understanding of the whole province.”
“Our wastewater surveillance data has been used by the Medical Office of Health to make decisions about investigations for COVID in long-term care, so it has been directly linked to public health action.”
Sewage testing is useful to track — and might even predict — activity of COVID-19 within a geographic region because it is not reliant on self-reporting of infection, said Bonita Lee, co-lead of the U of A team and associate professor of pediatric infectious diseases.
“It’s non-discriminatory,” Lee said. “Anyone who contributes to the sewage and is shedding COVID virus will be captured, whether or not they have sought testing or treatment.”
Data will support public health policies
Lee and Pang have also teamed up with EPCOR, Edmonton’s water utility, to test sewage from individual long-term care facilities because it is sensitive enough to pick up even one case and serve as an early warning system for outbreaks within a specific, vulnerable population.
“Our wastewater surveillance data has been used by the Medical Office of Health to make decisions about investigations for COVID in long-term care, so it has been directly linked to public health action,” Pang said.
The wastewater treatment plant data will be most useful to track changes in each municipality’s COVID-19 burden over time, she noted, because the Edmonton and Calgary teams use different methods.
Also, results can be affected by a range of local factors including industrial discharge, stormwater runoff from rain or snow melt, and visits by non-residents to tourist areas.
“The sensitivity is different depending on the population served by the wastewater treatment plant,” Lee said.
Wastewater viral monitoring is not meant to replace individual COVID testing because it doesn’t diagnose individual cases, nor does it indicate the age of those infected — a key factor in predicting how severe their illness could be and how much strain those patients might put on the health-care system.
This wastewater viral monitoring system could also be used in the future to monitor for other enteric viruses that affect the digestive system. Norovirus, a highly contagious virus that causes gastrointestinal illness, is of particular concern according to Pang, who is also a program leader for Alberta’s Public Health Laboratory and runs the only lab in the country that can culture enteric viruses to evaluate infectious viral levels. Influenza could not be tracked using this method because it sheds mainly through the respiratory tract rather than the gut.
The Pan-Alberta Network for Wastewater-based SARS-CoV-2 Monitoring is a partnership between the two universities, Alberta Health, Alberta Health Services and the participating municipalities. The Government of Alberta has provided $3.4 million to fund the project.