Chronic Wasting Disease (CWD), often referred to as "zombie deer disease," is posing a significant threat to wildlife across the United States and beyond. This neurodegenerative disorder, which affects the cervid family including deer, elk, moose, and reindeer, was first identified in free-ranging deer in Colorado and Wyoming back in 1981. Today, CWD has spread to 36 U.S. states, parts of Canada, Scandinavia, and even South Korea, raising global concerns about its potential to become an international crisis.
The disease is caused by prions, which are abnormal and transmissible pathogenic agents. Unlike bacteria or viruses, prions are notoriously difficult to destroy and have demonstrated an ability to remain active in soils for years. This persistence poses a significant risk as animals coming into contact with contaminated areas can become infected. The symptoms of CWD are alarming, featuring drooling, emaciation, disorientation, a vacant gaze, and a lack of fear of humans—characteristics that have led to its nickname. However, the term "zombie deer disease" has been criticized by experts who emphasize the real and serious nature of this disease.
“It leaves readers with the false impression that this is nothing more than some strange fictional menace you’d find in the plot of a sci-fi film. Animals that get infected with CWD do not come back from the dead. CWD is a deathly serious public and wildlife health issue.” – Osterholm
The spread of CWD has been insidious and relentless. The disease can only be diagnosed post-mortem, complicating efforts to control its spread. Despite its deadly nature among wildlife, there has yet to be a documented case of transmission to humans. However, scientists remain cautious due to the long incubation periods that could obscure the true presence of the disease in humans.
Roffe, an expert closely monitoring the spread of CWD, highlighted the slow yet inevitable expansion of the disease.
“This has been a slowly expanding epidemic with a growth curve playing out on a decades scale, but now we’re seeing the deepening consequences and they could be severe,” – Roffe
Alarmingly, there is no unified international strategy to prevent the spread of CWD. The United States appears unprepared for a potential spillover of CWD into human populations. With tens of thousands of people potentially consuming contaminated game meat, either out of ignorance or denial, the risk continues to grow.
“Unfortunately, what’s happening with this disease was predictable and we’re living with the consequences of some decisions that were rooted in denial.” – Roffe
The practice of feeding elk and deer has come under scrutiny from conservationists who believe it exacerbates the problem by concentrating animals and increasing their vulnerability to infection.
“Wyoming has wilfully chosen to ignore conservationists, scientists, disease experts and prominent wildlife managers who were all saying the same thing: stop the feeding,” – Dorsey
“It would be such a shame if we continued doing something as foolish as concentrating thousands of elk and deer, making them more vulnerable to catching and spreading this catastrophic disease, when we didn’t have to.” – Dorsey
As CWD continues its silent march across continents, it highlights the urgent need for informed management strategies and international cooperation. The disease's ability to create long-lasting environmental contamination further complicates containment efforts. Prions left behind form toxic waste sites that pose ongoing threats to wildlife.
Despite no current evidence of human infection, scientists stress caution regarding the consumption of venison from potentially infected animals. This concern is amplified by cultural practices where hunters share venison widely within communities.
“Hunters sharing their venison with other families is a widespread practice,” – Osterholm