United States: Chronic wasting disease (CWD) is spreading rapidly across the United States, with new cases appearing in various states from coast to coast. This fatal neurodegenerative disorder primarily affects members of the cervid family, including deer, elk, and moose. There is currently no vaccine or cure for the disease.
Scientists have described CWD as a “slow-motion disaster,” first identified in free-ranging deer in Colorado and Wyoming in 1981. Since then, the disease has expanded across 36 US states, parts of Canada, Scandinavia, and even South Korea, where farmed deer and elk have been affected, according to theguardian.com.
Often referred to in the media as “zombie deer disease,” CWD causes symptoms such as excessive drooling, severe weight loss, confusion, and an empty, vacant stare. However, many experts dislike this nickname, as it downplays the seriousness of the issue. Epidemiologist Michael Osterholm warns that it trivializes a major public health and environmental crisis.
‘Don’t call it zombie deer disease’: scientists warn of ‘global crisis’ as infections spread across the US – The Guardian
— B (@anenigma420) March 20, 2025
Chronic wasting disease, spreads across the US in deer, elk and moose https://t.co/icQCwmAcdr
Osterholm, who serves as director of the Center for Infectious Disease Research and Policy at the University of Minnesota, has long voiced concerns about the potential for CWD to spread to humans. Five years ago, he urged lawmakers to take action, warning that infected deer consumed by humans could pose a serious risk. Though some dismissed his concerns at the time, more scientists are now echoing his warnings as the disease continues to spread.
In January 2025, researchers published a report titled Chronic Wasting Disease Spillover Preparedness and Response: Charting an Uncertain Future. A panel of 67 experts studying zoonotic diseases concluded that if CWD were to spread to humans, it could trigger a crisis affecting public health, the food supply, and the economy on both a national and global scale. The report found that the US is unprepared for such an event and that no coordinated international strategy exists to contain the disease.
As of now, no confirmed human cases of CWD have been reported. However, experts caution that the long incubation period of similar diseases, such as mad cow disease (BSE), could mean infections go undetected for years. Since CWD can only be diagnosed post-mortem, experts emphasize the need for better surveillance of both humans and wildlife, as per theguardian.com.
The risk of transmission is highest in states where hunting is popular, as many people consume venison without realizing it may be infected. A CDC survey found that 20% of US residents had hunted deer or elk, and over 60 percent had eaten their meat. Experts worry that tens of thousands of people may unknowingly consume contaminated games each year, particularly since sharing wild games among families is a widespread tradition. The CDC advises hunters to test animals before consuming them, but many do not follow this guidance.
Another concern is environmental contamination. Unlike bacteria or viruses, CWD is caused by prions—abnormal proteins that are extremely resistant to destruction. Prions can persist in soil for years, infecting animals that come into contact with contaminated areas. Research from the US Geological Survey shows that hunters frequently transport animal carcasses across state lines, further accelerating the spread of the disease.
In states where thousands of deer and elk carcasses are disposed of in landfills, scientists worry that prion contamination could create toxic waste sites. The long-term environmental impact remains uncertain but could be significant.
For decades, Lloyd Dorsey, a conservationist with the Sierra Club in Wyoming, has hunted elk and deer. But with CWD now widespread in the Greater Yellowstone area, he is increasingly concerned about its safety. Dorsey and other experts have urged state and federal governments to shut down feed grounds where deer and elk congregate, as these sites create ideal conditions for disease transmission, according to the reports by theguardian.com.
Despite scientific recommendations, Wyoming has refused to close nearly two dozen feed grounds, including the federally managed National Elk Refuge, which hosts over 8,000 elk. CWD has already been detected in the refuge. Former US Fish and Wildlife Service officials have warned that these policies are setting the stage for a major outbreak.
In addition to the risk of human infection, CWD poses a severe threat to wild cervid populations, which are central to American hunting traditions. A recent study in Wisconsin found that infected deer populations decline over time because deaths outnumber births, potentially leading to local extinctions.
If authorities resort to mass culling to control the disease, it could have devastating consequences for communities that rely on hunting for food and cultural traditions. Some studies suggest that allowing natural predators like wolves, bears, and mountain lions to manage infected populations could help curb CWD’s spread, but many states have adopted policies that drastically reduce predator numbers, according to theguardian.com.
As the disease continues to spread, experts stress the need for proactive measures, including better surveillance, stricter regulations on carcass transportation, and reconsideration of wildlife management policies. Yellowstone, often considered a model for conservation, has the opportunity to lead by example. However, without significant changes, the US may face a worsening crisis with long-term consequences for both wildlife and public health.