'Zombie deer' are now also appearing in Yellowstone National Park, and scientists warn against eating contaminated meat | the animals

Chronic wasting disease (CWD) is an infectious disease that affects the brain and central nervous system of deer and elk. For many years, hunters have witnessed deer acting strangely as a result of the disease. The animals lose weight dramatically, become lethargic and stagger on their legs, but it is the “empty look” in their eyes that has earned them the name “zombie deer.” The disease is fatal, and there is no cure or vaccine.

Meanwhile, CWD has become a veritable epidemic, especially after it also appeared in Yellowstone National Park. The largest population of land mammals in North America lives there. “This case puts CWD on the radar of widespread attention in ways it wasn't before — and ironically, that's a good thing,” said Thomas Ruff, a veterinarian and former chief of the Fish and Wildlife Service's Animal Health Division. “It is a disease that has enormous environmental impacts.”

Michael Osterholm, an epidemiologist and director of the University of Minnesota's Infectious Disease Center, describes the disease as a “slow-moving disaster.” Once a disease penetrates a habitat, it becomes very difficult to clean up the environment. Disease-causing germs can survive for years in dirt or other surfaces, and are resistant to disinfectants and even burning up to 600°C.

There are concerns that the disease is transmitted from deer and elk to other mammals or birds, and even humans. Osterholm compares CWD to mad cow disease that swept through the United Kingdom in the 1980s and 1990s. The disease also spread to humans through contaminated meat, and about 150 people eventually died from it. Fellow epidemiologist Corey Anderson said: “No one is saying it will happen for sure, but it is important for people to prepare.”

It is estimated that humans eat between 7,000 and 15,000 infected animals each year. As hunting season approaches in the United States, the US Center for Disease Control is once again calling on individual states to test hunted game for the disease, and certainly not to consume meat from deer that appears sick.