On the front lines of the fight against 'zombie deer' disease in Manitoba

A decades-long fear came true for hunter and veterinarian Erika Anseeuw in November of last year: chronic wasting disease had been detected in Manitoba for the first time.

The devastating disease was first detected in Canada in the mid-1990s, around the time she graduated from veterinary school with a master's degree in medical microbiology, and she's been following it since.

"Fortunately, in Manitoba, we only had our first case last year. I was very angry when it happened," said Anseeuw, who lives in Grosse Isle, Man., and works in Winnipeg.

The disease was first found in Manitoba in a mule deer in October 2021, near the Saskatchewan border. Another case was announced a few weeks later.

As a result, the province ordered a deer cull to control the spread of the disease last December.

As of late August, the disease had been confirmed in a total of five mule deer in western Manitoba, according to a provincial news release.

Chronic wasting disease can affect the brain and nervous system of members of the cervid, or deer, family, including white-tailed deer, mule deer, moose and elk.

The disease, which is always fatal to those animals, spreads easily through saliva, urine, feces, tissue and even through plants and soil. An animal can be infected with CWD for up to three years before showing signs of disease.

Late-stage symptoms include excessive drooling, salivating and urinating, and leave the animals unable to hold their heads up, giving them an almost zombie-like appearance — which has led to CWD sometimes being referred to as "zombie deer" disease.

Since it was first detected in Canada in 1996 on an elk farm in Saskatchewan, it has spread among wild deer populations in Alberta and now Manitoba, which signals to Anseeuw that the province could be on the brink of a serious problem.

"It's something that we need to pay a lot of attention to," she said.

The disease belongs to the transmissible spongiform encephalopathy, or TSE, family and is similar to mad cow disease.

Anseeuw was the president of the Manitoba Veterinary Medical Association during the mad cow disease crisis in 2003.

"We were lucky we nipped that in the bud when we did," she said.

Transmissibility to humans?

Although there is no evidence of transmission of the disease to humans, Health Canada recommends not eating meat from an infected animal. 

However, some researchers believe the disease — like mad cow disease — could be spread to humans, Manitoba government wildlife biologist Richard Davis said.

He recalls a research project conducted by the Canadian Food Inspection Agency, which involved macaques — "the closest to the human species that we can use for research," Davis said.

The monkeys were fed small portions of meat — the equivalent of one burger a week — from a white-tailed deer infected with CWD. They developed the disease and died.

But even if the disease doesn't infect humans, the stakes are high. For people who hunt for sustenance, a dwindling deer population could create food insecurity.

"Young animals get infected, [and] they die just when they're in their prime breeding [age]," said Davis. "They're no longer able to reproduce."

Manitoba has had a prevention and surveillance program in place for chronic wasting disease since 1997, the province says. For years, hunters have been required to submit samples of white-tailed deer and elk killed in specific zones, including most of the stretch along Manitoba's border with Saskatchewan.

That's a popular hunting area, with many outfitters located in the areas around Duck Mountain Provincial Park and Riding Mountain National Park.

Davis — who works at a provincial lab in the western Manitoba city of Dauphin, where samples of animals killed by hunters are tested for chronic wasting disease — estimates that 80 per cent of the animals killed in the area are being tested.

"Hunters are concerned about it. Overall, hunters are pretty law-abiding people," he said.

Months to get lab results

But experts are divided over the effectiveness of the monitoring program, because the samples submitted are not from mule deer — the species most likely to spread the disease.

All five detected cases in Manitoba to date have been in male mule deer. This past fall, the province allowed a mule deer hunting season — something that wasn't allowed before, since mule deer were listed as a threatened species under provincial legislation.

It also takes months to get test results back from the lab, and very few hunters will wait that long before eating their catch.

Davis estimates the province analyzes around 1,000 samples a year.

Between 32,000 and 39,000 hunting licences are issued every year. But those numbers don't include Indigenous hunters who do not require a licence, so the province has no clear picture of how many deer are killed every year.

Maria Arlt, acting director of the Wildlife and Fisheries Branch of the provincial department of Natural Resources and Northern Development, believes only a small number of people submit samples of the animals they kill.

That worries her, since the goal is to keep chronic wasting disease from becoming endemic and spreading to other cervids.

"I'm not sure why the public doesn't want to submit samples," she said in an interview with Radio-Canada.

Testing is "a benefit to us as well as a benefit to the public," since it gives hunters confidence "that they're ingesting meat and handling animals that … do not have CWD," said Arlt.

The province is working to increase the number of drop-off sites to make it easier for hunters to submit samples, and also wants to educate hunters, she said.

"We don't want to take anything from them. We're just trying to collect additional information.… We don't anticipate that there is extensive CWD, but we'd obviously like to confirm that."

Now that the disease is in Manitoba, Anseeuw is doing everything she can as a hunter and veterinarian to slow the spread and hopefully prevent it from escalating to the level of the mad cow crisis.

"When we had mad cow disease in Canada — like three cases — it shut down out borders for years."