Is Zombie Deer Disease a Threat to Humans?

Chronic Wasting Disease (CWD), commonly referred to as “Zombie Deer Disease,” is spreading among wildlife, particularly deer, moose, and elk. Although the disease primarily affects animals, concerns have been raised about the possibility of it transmitting to humans. Recent reports of sporadic Creutzfeldt-Jakob disease (CJD) in humans, especially among hunters who consumed meat from infected animals, have sparked alarms. However, there is no definitive evidence proving that CWD can be transmitted to humans, and further research is needed to assess the actual risks.

Key Points

What is Zombie Deer Disease (CWD)?
CWD is a neurodegenerative prion disease that affects cervids (hoofed mammals) such as deer, elk, and moose. The disease is caused by misfolded prion proteins, leading to brain cell death and symptoms in animals, including:

• Weight loss
• Excessive thirst and urination
• Poor coordination and balance
• Drooping ears
• Difficulty swallowing, leading to drooling, pneumonia, and eventual death

CWD spreads through direct contact with bodily fluids and waste or indirect contact with contaminated environments like soil, water, and food.

Human Risks
There is currently no conclusive evidence that CWD can infect humans. Although CJD is a prion disease in humans, no direct link between CWD and CJD has been established. Some hunters who ate infected deer meat developed CJD, but researchers have not been able to confirm that CWD was the cause.

Prior Disease and CJD
CJD can occur sporadically, be inherited, or be caused by medical interventions. Variant Creutzfeldt-Jakob disease (vCJD), which is caused by Bovine Spongiform Encephalopathy (mad cow disease), serves as an example of an animal-to-human prion disease. However, the structural differences between BSE and CWD prions make it unclear whether CWD could spread to humans in the same way.

Experimental Studies and Evidence
Laboratory studies using macaques and humanized mice have not conclusively shown that CWD can infect humans. Mixed results have been observed in studies on CWD transmission to different species. New research is raising concerns that CWD might potentially infect humans in an atypical form, complicating diagnosis.

Ongoing Surveillance and Research
Organizations like the CDC are continuing to monitor the spread of CWD and investigate its potential risks to humans. Researchers are developing live tests for CWD and studying potential mutations in prions that might increase the likelihood of animal-to-human transmission. The growing deer population due to climate change could lead to greater exposure to CWD.