Chronic Wasting Disease (CWD) is a serious, fatal neurological illness affecting cervids, which include deer, elk, and moose. Hunters and consumers are concerned about the safety and appearance of venison harvested in areas where the disease is present. Visual inspection alone is not a reliable method for determining if an animal is infected, but certain post-mortem signs can raise suspicion. Understanding the disease and how to safely handle a carcass is the primary defense against potential exposure.
The Nature of Chronic Wasting Disease
Chronic Wasting Disease belongs to a group of illnesses called Transmissible Spongiform Encephalopathies (TSEs), which are caused by infectious proteins known as prions. Prions are misfolded versions of a normal protein found in the brain and nervous tissue. Unlike bacteria or viruses, prions contain no genetic material and are extremely resistant to conventional sterilization methods like heat, radiation, or common disinfectants.
Once an animal is infected, these abnormal prions cause normal proteins to also misfold, leading to a chain reaction that damages the brain and nervous system, eventually resulting in death. CWD is highly transmissible among cervids, spreading through direct contact and indirectly through environmental contamination. Infected animals shed prions in bodily fluids, including saliva, urine, and feces. These prions can contaminate soil and water sources for years, posing a long-term risk to other animals.
Identifying Signs of CWD in Deer Meat and Organs
CWD is a disease of the nervous system, meaning the muscle tissue (meat) can appear completely normal even if the animal is infected. Infected animals can carry the disease for months or years before showing outward clinical signs. Therefore, a healthy-looking deer is not guaranteed to be CWD-free.
When an animal shows clinical signs, the most notable post-mortem observation is severe muscle wasting (emaciation). This extreme lack of body fat and muscle mass makes the ribs, hips, and backbone prominent. Suspicious signs also involve the lymphoid tissues and nervous system structures.
Hunters should look for enlarged or abnormal lymph nodes, especially the retropharyngeal lymph nodes, as prions accumulate heavily in these tissues. While the meat may look fine, severe emaciation, excessive salivation, or a lack of alertness in the live animal should prompt immediate testing and disposal. Definitive diagnosis is only possible through laboratory testing of the brain stem and specific lymph nodes after death.
Assessing Human Health Risks from CWD Consumption
There is no strong evidence that CWD naturally infects humans, and no human cases have been reported. However, CWD belongs to the family of TSEs, which includes Bovine Spongiform Encephalopathy (BSE), or “Mad Cow Disease,” which transmitted to humans. This connection makes CWD a theoretical risk to people.
Health organizations, including the Centers for Disease Control and Prevention (CDC), recommend against consuming meat from CWD-positive animals or any animal that appears sick. This precautionary measure is based on experimental studies showing CWD transmission to non-human primates. The prions that cause CWD are also not destroyed by normal cooking temperatures, unlike most bacteria or viruses.
The CDC advises hunters in CWD-endemic areas to have harvested deer or elk tested before consumption. If a commercial processor is used, request that the animal be processed individually to ensure the meat is not mixed with others. A “no prions detected” result does not guarantee the animal is uninfected, as prions may be at undetectable levels early on, but it significantly reduces the risk of exposure.
Essential Carcass Handling and Disposal Procedures
Safe handling of a carcass harvested in a CWD area centers on minimizing contact with and restricting the movement of high-risk tissues. Prions are most concentrated in the brain, spinal cord, eyes, spleen, and lymph nodes. Hunters should wear rubber or latex gloves when field dressing and should avoid cutting through the spine, brain, or skull.
Field dressing should leave as much high-risk material at the kill site as possible. Many jurisdictions restrict the transportation of whole deer carcasses or parts containing the spine or brain across state or zone lines. Acceptable parts for transport include:
- Deboned meat.
- Clean hides.
- Antlers.
- Skull plates cleaned of all tissue.
Proper disposal of inedible parts is necessary to prevent environmental contamination, as prions can remain infectious in the soil for years. Preferred methods for disposing of high-risk parts include:
- Designated CWD dumpsters.
- Commercial rendering facilities.
- Permitted solid waste landfills.
If an animal is processed at home, remaining carcass parts should be double-bagged and taken to an approved landfill or buried at least two feet deep, according to local regulations, to deter scavengers.