Ontario’s Ministry of Natural Resources and Forestry has proposed new measures to prevent a fatal deer disease from entering the province.
Chronic Wasting Disease, an untreatable brain disorder, is fatal to members of the cervid family, such as deer, elk, moose, and caribou, and is caused by infectious abnormal proteins known as prions. At this time there is no direct scientific evidence to suggest that CWD may be transmitted to humans.
“Chronic wasting disease is very different from other diseases we’re used to dealing with and that’s because of the nature of the infectious agent,” says Keith Munro, a wildlife biologist with Ontario’s Federation of Anglers and Hunters.
“It’s not a bacteria; it’s not a virus; it’s not a parasite. It’s really just a misfolded protein.”
The protein is spread through the saliva, urine, feces, and blood of infected animals, and can live on plants and in the soil for years. Once infected, the disease bores holes in the animal’s brain, causing it to behave in a trance-like manner, stumbling with its head and ears drooped, salivating excessively, losing its fear of humans, and, as the name indicates, wasting away. “It’s a very terrible death,” Munro says.
The symptoms, however, can take up to two years to surface, appearing right before the animal dies. This makes it nearly impossible to detect the disease in its early stages.
“If we wait for people to see sick deer, that’s going to mean there are a whole lot of deer that are infected but not showing symptoms,” Munro says.
Prior to exhibiting symptoms, the disease can only be detected by extracting samples from a dead deer’s brain and lymph nodes (the areas where CWD tends to concentrate).
This is where hunters play an imperative role. By submitting harvested deer samples to either the MNRF or the Canadian Wildlife Health Cooperative, based out of the University of Guelph, hunters can help detect CWD in its early stages. “If you don’t have hunting, you don’t have surveillance,” he said.
The disease is typically found in mature, adult males and females because of the way they move and interact with the landscape. By infecting this demographic, the disease can cause wildlife populations to stall and even decrease. “Basically, you’ve removed the real reproductively productive members of the population,” Munro says.
CWD has yet to be detected in Ontario despite being identified in 26 U.S. states—including neighbouring states, such as Michigan—and three Canadian provinces: Alberta, Saskatchewan, and Quebec. According to the Canadian Food Inspection Agency, the disease was first detected in Canada on a Saskatchewan elk farm in 1996. “Saskatchewan has it to a level where they’ll never be able to get rid of it,” Munro says.
Once the disease has set root in an area, it is notoriously difficult to manage. New York State is the only jurisdiction to successfully rid itself of CWD. Ontario is hoping to imitate that success by modelling its new preventative measures after New York.
This includes restricting the exportation of live animals from areas where CWD has been detected, creating response zones with special rules for disease testing, and authorizing hunters to dispatch of symptomatic animals in specific areas.
While Munro applauds these new preventative measures, he says more steps are needed. “We are asking the government to go even further and get rid of deer farms.”
According to Munro, deer farms are the primary catalyst for spreading CWD. Due to it being impossible to test live animals for the disease, farmers have no way of knowing if their animals are infected when transporting them.
Good news: “zombie deer” disease (probably) can’t be transmitted to humans
If the disease jumps from the farmed animals to the wild, Munro says the only way to stop the spread of CWD would be to kill the local deer population. “It’s a pretty drastic response, I’ll be honest, but it’s necessary,” he says. “If you don’t do it, you’ll always have CWD.”
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