Chronic wasting disease, an illness that lethally infects the brains of animals like deer, continues to expand in Canada and has been identified for the first time in a new province. The B.C. government revealed on Thursday that two cases of the disease were found in deer south of Cranbrook. Previously, scientists had already observed it in 34 U.S. states and four other provinces. The disease, highly contagious and affecting members of the cervid family such as moose and elk, infects their brains. Symptoms include severe weight loss, paralysis, and pneumonia, leading to the isolation of the affected animals from the rest of the herd. It is always fatal with no available vaccine or treatment. University of Calgary veterinary professor Sabine Gilch commented, “The discovery in B.C. is very concerning because usually if there are two animals that are detected, then there will be more.”
Researchers have highlighted that the spread of the disease is worrying as it poses a threat to deer and elk populations. Moreover, the wider the spread, the greater the chances of transmission to other animals. Although research suggests that it is unlikely for chronic wasting disease to jump to humans, the absence of vaccines or treatments makes the possibility of human infection unsettling.
Chronic wasting disease is caused by prions – a misshapen version of naturally occurring proteins in the brain. This poses a challenge as the body does not recognize the prions as foreign proteins, unlike viruses or bacteria, leading to no immune response. Creutzfeldt-Jakob disease and bovine spongiform encephalopathy (BSE), which causes mad cow disease, are also attributed to prions. Another concern is that chronic wasting disease causes increased drooling and urination, and infected animals excrete prions through saliva and urine. Prions can bind to soil, potentially allowing another creature to ingest them when consuming vegetation, leading to disease transmission, even years later.
The prevalence of chronic wasting disease in many areas has posed additional challenges due to high contamination levels in the environment. University of Alberta researcher Debbie McKenzie emphasized the issue, stating that some areas have over 50 percent of male deer being positive for the disease. Infected animals may appear healthy, but this limits their breeding seasons and results in smaller populations within herds. It is predicted that the disease will continue to cause fatalities and decrease animal populations.
There is also concern that chronic wasting disease could jump to caribou, which are already endangered. Unlike mad cow disease, sick deer cannot be culled as they are not domesticated and exist in uncontrollable wilderness environments. Although current studies suggest that the disease is not highly likely to cross into human and livestock that are commonly consumed, its widespread presence in Western Canada is raising concerns.
To minimize the risk, hunters are urged to test all deer and elk before consumption. Canadian law mandates the reporting of all infected animals or those with suspected infections to a regional Canadian Food Inspection Agency veterinarian. Additionally, the law requires chronic wasting disease testing for all farmed cervids older than one year slaughtered in certain Canadian provinces. Despite being discovered in 1967 in the U.S., efforts to contain the disease have failed to halt its spread. It is essential for British Columbia to conduct extensive surveillance to understand the disease’s spread and provide support to hunters for deer testing. Even without demonstrated transmission to humans, there is still concern about chronic wasting disease.
