Chronic Wasting Disease Transmission to Humans
No confirmed cases of humans contracting Chronic Wasting Disease (CWD) from deer have been documented, but caution is warranted as prion infectivity has been found in deer skeletal muscle, posing a potential risk to humans who consume or handle meat from CWD-infected deer. 1
Understanding Chronic Wasting Disease
Chronic Wasting Disease is a prion disease affecting members of the cervid family, including deer, elk, reindeer, and moose. It is characterized by:
- Progressive weight loss
- Abnormal behavior
- Excessive salivation
- Neurological deterioration
The disease has been expanding geographically from North America to new areas, including South Korea and Norway 2.
Transmission Risk to Humans
Current Evidence
- No strong evidence exists for a causal link between venison consumption and CWD transmission to humans 3
- A 2001 investigation of three unusually young CJD patients who consumed venison found no conclusive evidence of CWD transmission 3
- However, more recent research (2006) demonstrated that skeletal muscles of CWD-infected deer contain infectious prions 1
Risk Factors
The potential for human exposure exists through:
- Consumption of infected meat
- Handling of infected animals or carcasses
- Contact with contaminated environments
Environmental Persistence and Transmission
CWD has concerning transmission characteristics:
- Can be transmitted indirectly through environments contaminated by excreta or decomposed carcasses 4
- Prions can persist in the environment for years (at least 2.2 years documented) 4
- Transmission occurs horizontally via saliva, feces, and urine 5
- Environmental reservoirs exist in soil and water 5
Recommendations for Risk Reduction
While no specific guidelines address CWD transmission to humans directly, we can apply principles from guidelines on animal-human disease transmission:
Avoid contact with high-risk animals:
- Similar to recommendations against contact with rabies-reservoir species, avoid handling deer showing signs of CWD 6
Practice proper hygiene:
- Thorough hand washing after any potential exposure to deer or their environment 6
Take special precautions for high-risk populations:
- Immunocompromised individuals, pregnant women, older adults, and young children should take heightened precautions 6
Consider avoiding consumption of venison from areas with known CWD:
- While not explicitly stated in guidelines, this follows the precautionary principle given the detection of prions in skeletal muscle 1
Conclusion
While the zoonotic potential of CWD remains uncertain, the presence of infectious prions in deer skeletal muscle suggests that humans consuming or handling meat from CWD-infected deer are at potential risk of prion exposure. Until more definitive evidence emerges, precautionary measures are warranted, especially for those who frequently handle or consume deer meat from areas where CWD is prevalent.