Chronic Wasting Disease maintains high prevalence, spreads to Western Wyoming (2024)

The Wyoming Game and Fish Department's latest survey has found 14% of hunter-harvested animals are infected with chronic wasting disease.

The disease which is fatal to cervids— such as moose, elk, and several species of deer — has become an increasing concern for wildlife managers and sportsmen, who are encouraged by the Centers for Disease Control and Prevention not to consume meat from infected animals.

Chronic wasting disease, a cervid-specific neurological disease, is the result of misfolded proteins known as prions, which infect the central nervous system and cause progressive weight loss and excessive salivation. Infected animals appear lethargic and have drooping ears. While the disease is 100% fatal in cervids, and no confirmed cases have been found in humans, transmission to humans is extremely unlikely, but not impossible federal health experts fear.

The survey results are similar to figures from 2022 but mark a continued climb from 2021 when only 12% tested positive. The number of submitted samples have dropped, though, as the results included only 5,100 samples, down from 5,875 in the previous survey and down from 6,884 in 2021–a trend that experts hope to see reversed as comprehensive sampling is an important part of the department's long term efforts to manage CWD’s spread.

“There are areas where we have insufficient data, just too low sample size to give an accurate prevalence. So we’d like to get more hunters interested in at least giving us a sample,” said Wyoming Game and Fish Wildlife Disease Specialist Jessica Jennings.

The disease has been most prevalent in mule deer herds, but was also found in white-tailed deer, elk and moose. The survey shows that the disease is gaining fast traction in some elk populations, appearing for the first time in herds in western Wyoming, including in Yellowstone National Park.

“It's a little concerning that we had four new elk hunt areas and that they are moving over into the western part of the state,” Jennings said.

The survey data is limited to voluntarily submitted samples of hunter-harvested, adult male animals. And while the disease has increased in mule deer, white-tailed deer and elk populations statewide, prevalence is especially high in some areas. For instance, the mule deer herd in central Wyoming saw 65% of hunter-harvest males test positive for CWD; the Greybull River herd showed a 46.2% positivity, and the Shoshone River herd was at 39%.

As the disease spreads, pressure is building on wildlife managers, who concede the problem may never be eradicated. Infections can be transmitted through a mother’s milk and other bodily fluids. And because prions reside in the environment for long periods — sometimes surviving in soil for decades — animals can be infected as they forage for food.

With eradication seen as unlikely, “ the plan is more focused on trying to implement strategies designed to at least reduce the potential transmission spread and prevalence of the disease,” Wyoming Game and Fish wildlife biologist Justin Binet said.

The department’s CWD management plan aims to reduce transmission through strategies including tactical culling, and eliminating feeding bands and “artificial sources of concentration.”

Active management has been a source of controversy in wildlife communities, as some people believe the best practice is not to manage, but to let nature run its course. Binet and Wyoming Game and Fish officials, however, say that nature’s course has been the status quo since CWD was first detected decades ago, and that the stakes are getting too high to continue a hands off approach.

“When you’re talking about a disease that’s 100% fatal and you start finding it in 30% and 40% of your bucks that doesn't bode well for the health of those herds.”