Photo credit: Hamilton Greenwood
I stare at the carefully folded package on the kitchen table. Neat straight edges in the paper wrapping protect the contents inside. Every year, my partner’s father gifts us this way with deer sausage. He has been involved in all stages of its preparation; from hunting the animal, to smoking the meat in his backyard, to shipping the products of his work across three provinces for us to ration until the arrival of our next treasure. But this year I am hesitant to open the package, and I stand here wondering – are these safe for me to eat?
Chronic wasting disease (CWD) is challenging our confidence that the wild game we consume in Canada are healthy. Named for its degenerative effects on the brains of “cervids” such as deer, elk and moose, this devastating infectious disease is a death sentence. Since 1996, CWD has spread throughout western Canada, transmitted among animals in their urine, feces, and saliva.
And while CWD threatens the conservation of cervid species, it also challenges our perceptions of the types of organisms that cause disease. If you were to assemble a line-up of the “usual disease suspects”, you would see viruses, bacteria and parasites — all of them awkwardly avoiding eye contact, trying to appear innocent. What you wouldn’t see is the true culprit behind CWD: A protein that looks very like a normal part of the animal’s biology. The only difference is that this protein is misfolded — bent into a shape that turns a productive member of society into a killer.
Prions, as these misfolded proteins are called, belong to a group of disease-causing agents called “Transmissible Spongiform Encephalopathies”. Among its relatives is the particle that causes “mad cow disease”, a pathogen of cattle that is transmissible to people through the consumption of infected meat. Unlike mad cow disease, there has not yet been a case of CWD in people. However, the potential for transmission to humans is concerning. Recent research led by Dr. Stefanie Czub demonstrated that CWD can be transmitted to non-human primates through the consumption of infected meat. These risks are complicated by the reality that clinical signs of prion-associated diseases often remain undetected for decades. The uncertainty around cross-species transmission has led both the World Health Organization and Health Canada to recommend that CWD-positive animals not be consumed by people.
Once in the environment, CWD is nearly impossible to eradicate. These pesky prions are incredibly persistent in the environment, binding to the soil and to plants until they are consumed by an unsuspecting deer. This is why the best defense against CWD is preventing it from getting a foothold. Prevention has been the focus in British Columbia, where since 2002, the province has tested cervids for CWD as part of its Wildlife Health Program. While there has yet to be a case of CWD in BC, in February 2019 the disease was detected for the first time west of the Rocky Mountains in Libby, Montana, just 50 km south of BC’s border. According to Cait Nelson, a wildlife health biologist with the Government of British Columbia “the detections there have significantly increased the risk to BC”.
To address the potential threat advancing on its southern border, the BC government is calling on hunters to assist in the fight against CWD. Beginning in the fall of 2019, a change to the Animal Health Act will require hunters along the BC/Montana border to submit the heads of any harvested mule deer or white-tailed deer for testing. By submitting the heads from harvested deer, the province will be better able to detect CWD and prevent its spread to other animals, which will in turn improve the government’s ability to conserve wild cervids for future generations of hunters. In return, hunters will be provided with testing information to ensure before they eat their game that the harvested animals are CWD-negative. Hunters can find information about where to deposit their harvested animals on the Government of British Columbia’s website.
I think about this call to action for hunters as I consider my breakfast. I know that my partners’ father has not had this deer tested. And, whether or not CWD is transmissible to people, it presents an unknown risk with potentially severe consequences. This is why confidence in a healthy wildlife population is so important. Without it, it inhibits our ability to make informed choices about the food that we eat and impacts our relationship with hunting more broadly. I tangle with the word “uncertainty” for what feels like an hour. In the end, I decide I would rather be certain, and the deer sausage goes back in the freezer.