Chronic wasting disease: what hunters should know

If you hunt, handle or eat 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 among 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.

As a precaution, the Government of Canada recommends that people not consume any part of an animal that has tested positive for CWD.

In Canada, CWD has been predominantly found in wild and farmed deer and elk populations in Saskatchewan and Alberta. 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. It has not been detected in wild caribou anywhere in North America.

There are a number of actions people can take when hunting to reduce their potential risk of exposure to CWD when handling animals in the deer family.

How to protect yourself

• Before you hunt, check with your provincial or territorial wildlife management office to see whether CWD has been found in the area, and whether testing is available or required for CWD
• People in the area of Alberta, Saskatchewan or Quebec where CWD has been found, should have their animal tested for CWD before eating the meat, preparing trophies or harvesting hides
• Pay attention to the appearance and behaviour of the animals you are hunting
• Do not harvest an animal that appears to be sick and report sick or dead animals to your provincial or territorial wildlife authority
• Avoid handling or eating an animal or parts of an animal that has died from unknown causes or has tested positive for CWD
• When handling carcasses, wear latex or rubber gloves and avoid handling or eating the animal's brain, spinal cord, eyes, spleen, tonsils or lymph nodes. If you use parts of the carcass to tan the hide, minimize handling of the animal's head and brain
• Wash hands and tools thoroughly with soap and water after field dressing is completed. Tools should then be disinfected with bleach, as this substance can decontaminate surfaces contaminated with CWD prions
• Appropriate disposal is also important to reduce the risk of spread of CWD. Contact your provincial wildlife management office for information
• If you have the animal commercially processed, ask that your animal be processed individually, without meat from other cervids being added

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 of testing

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 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

Related links

• Canada.ca: Chronic Wasting Disease
• CFIA: Chronic wasting disease (CWD) of deer and elk
• Tips on food safety when hunting