Collaborative surveillance team detects SARS-CoV-2 virus in Saskatchewan white-tailed deer

The team, whose members are from the University of Saskatchewan (USask), Environment and Climate Change Canada (ECCC), Saskatchewan Ministry of Environment, and Canadian Wildlife Health Cooperative (CWHC), found positive results in viral RNA swabs taken from four white-tailed deer harvested in 2021.

The National Centre for Foreign Animal Disease (NCFAD) confirmed the results, which represent two per cent of 227 white-tailed deer tested in Saskatchewan. Ten per cent of 62 white-tailed deer tested also had SARS-CoV-2 antibodies—indicating previous exposure or active infection.

While white-tailed deer in Ohio and multiple Canadian provinces have tested positive for SARS-CoV-2 virus, the team’s results represent the first detections among Saskatchewan deer.

“For some reason, deer are susceptible to infection, and not only that, when the virus gets into deer it spreads through the population very rapidly,” said Dr. Vikram Misra (PhD), a USask virologist at the Western College of Veterinary Medicine (WCVM).

SARS-CoV-2, the coronavirus that causes COVID-19, is transmissible between people and animals. Once it became widespread in 2020, scientists suspected the virus could inevitably spill over from humans to susceptible animal species. 

“The concern is if it gets into a wildlife reservoir, then the virus will obviously change in very, very unpredictable ways. And then there’s always the possibility of it going back into people from this reservoir,” said Misra.

He describes the project as a “perfect One Health problem,” intersecting animal, human and environmental health and bringing together experts in wildlife health, virology, molecular microbiology, pathology, parasitology, zoonoses and public health.

Dr. Emily Jenkins (DVM, PhD) is a WCVM researcher who conducts wildlife and public health research studies in the North. Early in the pandemic, she received questions from Indigenous people who rely on wildlife for food and their livelihoods.

“We initiated this surveillance to reassure people about the wildlife that they’re handling and consuming,” said Jenkins, adding that SARS-CoV-2 isn’t foodborne and the risk of contracting the virus from harvested wildlife is minimal.

Jenkins and Misra worked with Drs. Darryl Falzarano (PhD), Christy Morrissey (PhD) and Trent Bollinger (DVSc) of USask as well as Dr. Catherine Soos (DVM, PhD) and researcher Bruce Pauli of ECCC to obtain grants from the Natural Sciences and Engineering Research Council of Canada (NSERC) Alliance, ECCC and the Public Health Agency of Canada.

With support secured, Jenkins’s WCVM lab and the Wildlife Health Lab (managed by Soos) at the ECCC Prairie and Northern Wildlife Research Centre in Saskatoon became RNA viral testing sites.

Misra and his lab developed a test for identifying SARS-CoV-2 antibodies in blood from various animal species. Most tests for people and animals only detect antibodies against the virus’s spike protein, but this new test also detects a couple of other proteins.

“It’s pretty unique because it takes into account the changes that the virus may undergo in a different species,” said Misra.

Soos, an ECCC wildlife health specialist and an adjunct professor at the WCVM, leads Canada’s efforts to conduct surveillance for SARS-CoV-2 and other coronaviruses in wildlife. That role put Soos in contact with partners who could tap into existing surveillance or research programs for samples.

“A positive outcome … is that co-ordinating, communicating and working closely with all the other relevant agencies and partners across the country has really strengthened Canada’s network and ability to tackle emerging One Health issues,” said Soos.

Dr. Iga Stasiak (DVM) is a wildlife health specialist with Saskatchewan’s Ministry of Environment. She helped the team partner with the province’s chronic wasting disease (CWD) surveillance program, which also involves the CWHC in Saskatoon, Sask.

“Every year, we have hunters from across Saskatchewan who submit deer heads for CWD testing—we felt that was a great opportunity to collect samples for coronavirus testing,” said Stasiak. “Given that white-tailed deer are susceptible to the virus, we wanted to definitely look for it here in Saskatchewan to see if it was also the case.”

In 2021, technicians collected oral and nasal swabs and blood samples from over 300 deer heads at a Regina processing lab. CWHC (Western/Northern Region) also collected samples from submitted deer and other cervids.

Saskatchewan’s SARS-CoV-2 surveillance team analyzes samples from ECCC, Parks Canada, B.C., Alberta, Saskatchewan, Manitoba, the Maritimes and northern territories. Toronto’s Sunnybrook Research Institute tests samples from Ontario and Quebec. NCFAD conducts final confirmatory testing for all positive samples in Canada. 

Canadian labs have tested over 1,400 samples from cervids with positive results detected in Quebec, Ontario, Manitoba and B.C., reported Soos. Canadian labs have also tested over 1,600 samples (all testing negative) from other wildlife species.

“We are receiving samples from every province and territory, a truly national surveillance effort … and actually contributing to understanding how this virus is moving around and mutating in wildlife,” said Jenkins.