What is chronic wasting disease (CWD)?
Chronic wasting disease (CWD) is a nervous system disease that affects animals in the deer family (cervids). It causes death in these animals, but infected animals may not show any symptoms for months or years after being infected. CWD is much more common in deer, but it is also found in moose and elk.
CWD is part of a group of diseases that includes:
CWD occurs in some parts of Alberta, from Cold Lake south to the United States border. See the map of locations where CWD has been found in Alberta. It has also been found in wild game (cervids) in Saskatchewan, the United States, Norway, and South Korea.
Does CWD infect people?
There is no direct evidence that CWD has ever been transmitted to humans like mad cow disease (the human form of mad cow disease is vCJD). However, some research shows that CWD can be transmitted to monkeys closely related to humans by feeding them meat or brain tissue from deer and elk infected with CWD. Because of this, you should use the information below to lower your risk when eating or handling deer, elk, caribou, and moose meat.
What causes CWD and how does it spread?
Diseases like CWD and mad cow disease are caused by infectious proteins called prions (say “PREE-ons”). In CWD, these proteins are found in the brain, spinal cord, lymph nodes, spleen, and muscle tissue. Prions cause small holes to appear in the affected areas of the brain, causing the animal’s brain function to slowly get worse over time. The holes caused by prions can make affected brains look like sponges.
CWD is thought to spread between animals by:
- direct animal-to-animal contact
- contact with saliva, urine, carcass parts, or feces from infected animals
- soil that has been contaminated with infected tissues or fluids
How can I lower the risk of CWD?
Alberta Health recommends that any animals from the deer family that are harvested from areas where CWD has been
found should be tested before you eat any parts of the animal, as infected animals may not show any symptoms for months or years after being infected. A negative test result does not guarantee that the animal is not infected with CWD, but does make it less likely. Find out more about testing services for CWD.
A number of health organizations continue to gather evidence and check for any potential human health risk of CWD.
Other ways to lower your risk:
- Do not handle or eat meat from any animal that appears sick.
- Do not handle or eat meat from any animal that has died from unknown causes or has tested positive for CWD.
- Avoid eating the brain, spinal cord, spleen, and lymph nodes of any harvested animal. If the animal is infected, these parts may have high concentrations of prion. Cooking temperatures do not destroy prions.
- Follow best practices for handling game animals:
- wear protective gloves
- handle organs and nervous tissue as little as possible (leave high-risk body parts at the kill site)
- wash your hands with soap and water
- disinfect instruments after handling carcasses
If you want to keep the skull or antlers after harvesting, remove all the brain tissue from the skull and connecting bone plate, then disinfect the bones with a 10% bleach solution. A 10% bleach solution means mixing 1 part bleach with 9 parts water, like mixing 100 mL of bleach with 900 mL of water.
If you want to tan a hide or have a hide tanned after harvesting, remove all tissue, seal the hide in plastic or a sealed container, freeze it, and start tanning as soon as possible.
- If someone gives you deer meat, ask where it was harvested. If it was harvested in an area where CWD is found, ask if it was tested. See the map of locations where CWD has been found in Alberta.
- If you have your wild game commercially processed, ask that your animal be processed on its own, without meat from other animals added to it.
Restaurants that sell venison (like deer or elk meat) or other game meat get their meat from a farm. All of these animals are tested and must be shown to be negative for CWD before they are sold. The risk of eating infected meat in a restaurant is therefore considered to be very low.
Where can I find the latest information about CWD?
These organizations are tracking and studying CWD. Their websites have the most up-to-date information about this disease.
