Veterinarians on Alert: The Alarming Rise of a Fatal 'Zombie Deer Disease

In a startling development, hunters across North America are unwittingly finding themselves on the front lines of a public health threat due to chronic wasting disease (CWD), a rapidly spreading and always fatal neurological condition affecting deer. Infectious disease experts are raising alarms about the potential risks of this disease, which is caused by misfolded proteins called prions and currently known to infect only members of the cervid family, including elk, deer, reindeer, caribou, and moose.

The threat of CWD is highlighted by recent research showing that the barrier to spillover into humans is less formidable than previously thought, with prions potentially evolving to become more capable of infecting humans. In response, a coalition of 68 global experts has been mobilized in 2023 to address the challenges ahead, should there be a spillover into humans and food production. Michael Osterholm, an infectious disease expert at the University of Minnesota, has underscored the urgency of the situation, noting that we are currently unprepared for such an eventuality.

The problem is compounded by the fact that tens of thousands of infected animals are consumed by people each year, with no known human cases of the disease to date. Many hunters, including Steve Rinella, founder of MeatEater, a hunting and cooking wild game media company, are grappling with the seriousness of the CWD threat.

CWD, first discovered in Colorado in 1967, has since spread to at least 32 states, four Canadian provinces, and four other countries, including Yellowstone National Park. Prions, which are highly resistant to destruction, cause symptoms that have earned the disease the nickname “zombie deer disease.” Affected animals exhibit behaviors such as stumbling, drooling, and blank staring before succumbing to the disease. No treatment or vaccine is currently available.

Despite the absence of known human cases, the concern is palpable. Researchers estimate that between 7,000 and 15,000 infected animals are consumed annually by hunter families, a number increasing each year as the disease spreads. While testing for CWD in wild game is available, it is cumbersome and not widely used.

The disease's long latency period poses a major challenge in determining its impact on humans. People who consume prions may not develop the resulting disease for many years, making it difficult to establish a direct connection to consuming deer.

Efforts to combat CWD include quick testing of deer and other cervids, with researchers and experts working to develop rapid tests to increase the number of animals tested. In Montana, where CWD was first detected in 2017, the response among hunters has been tepid despite warnings and free testing.

Indigenous communities, recognizing the cultural significance of deer hunting, are proactively working with experts to manage the disease. The Minnesota Center for Prion Research and Outreach is spearheading efforts to understand and mitigate the risks associated with prions, including developing faster and easier testing methods.

Peter Larsen, an assistant professor at the University of Minnesota and co-director of the center, emphasizes the importance of learning about CWD and other prion-like diseases to protect animal health and welfare. With new solutions on the horizon, there is a glimmer of optimism in the fight against this daunting disease.