Chronic wasting disease: what you need to know
If you consume products derived from deer, elk, caribou or moose, you should know about Chronic Wasting Disease (CWD).
CWD is a progressive, fatal nervous system disease that affects these animals, which are all part of the deer family known as cervids. It is a transmissible spongiform encephalopathy, or prion disease. It is contagious amongst cervids, like scrapie in sheep. There has been no known transmission of CWD to humans, however, bovine spongiform encephalopathy (also known as mad cow disease) in cattle has been known to cause Creutzfeldt-Jakob disease in humans.
In Canada, CWD has been predominantly found in the wild and farmed deer and elk populations in Saskatchewan and Alberta and there have been 3 confirmed cases in wild moose. The disease has also been found in farmed red deer in Quebec and in a wild deer in Manitoba. It has not been detected in wild cervids in other provinces or territories in Canada, and has not been detected in wild caribou anywhere in North America.
There is no known transmission of CWD to humans. However, as a precaution, the Government of Canada recommends that people not consume any part of an animal that has tested positive for CWD.
How to protect yourself
- Buy your meat through a retailer so you can be sure that the meat comes from an establishment licensed by the federal or provincial government. Animals and related products harvested from animals known to be infected with CWD are prohibited from entering Canada's food supply
- If you are given hunted deer meat, ask whether the animal was hunted in an area where CWD has been found and whether it was tested. Do not consume meat from a known CWD-infected animal or untested meat from cervids in areas where CWD has been found
Material from known CWD-infected cervids is not permissible for use in natural health products (NHPs). Consumers are encouraged to use all the available label information when selecting health products to meet their needs. Canadians may wish to avoid consuming NHPs that contain materials from cervids, since the existence of a potential risk cannot be definitively excluded. To date, Health Canada is not aware of any documented cases of CWD infection in humans.
How is CWD diagnosed and what are the limitations
Although animals infected with CWD sometimes show symptoms, CWD can only be confirmed by testing specific tissues from an affected animal after it is dead. While a negative test result still does not guarantee that an individual animal is not infected with CWD, it is considerably less likely and may reduce your potential risk of exposure to CWD.
Currently, CWD tests officially approved by the Canadian Food Inspection Agency (CFIA) are designed for surveillance purposes and are not reliable enough to detect the disease in animals under 12 months of age. CFIA's surveillance testing aims to identify farmed animals over 12 months of age (who are more likely to be infected with CWD), in order to prevent contaminated meat or other consumable products from entering the market. There is currently no test available to certify that food or other consumable products are free from the CWD prion.
What we know about CWD and human health
There has been no known transmission of CWD to humans. Extensive surveillance of human prion diseases in Canada and elsewhere has not provided any direct evidence that CWD has infected humans. However, experts continue to study CWD and whether it has the potential to infect other animals and humans. As a precaution, measures are in place to prevent known infected animals from entering the food chain, including:
- mandatory testing of all cervids sent for slaughter (over the age of 12 months) at all abattoirs in Saskatchewan, Alberta, Manitoba, Yukon and Quebec
- not allowing animals known to be positive for CWD to enter the commercial food chain
- reporting immediately to the CFIA all suspected cases, as CWD is a reportable disease under the Health of Animals Act
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