CHEYENNE, Wyo. — The Wyoming Game and Fish Department’s (WGFD) Wildlife Health Laboratory saw an increase in the prevalence of chronic wasting disease (CWD) in the state’s mule deer populations, the agency has announced.

WGFD said it tested for CWD in more than 5,000 samples taken from mule deer, white-tailed deer, elk and moose, including hunter-harvested, targeted and road-killed animals. Of those samples tested, 19.4% came back positive in hunter-harvested mule deer bucks, 29.2% in hunter-harvested white-tailed bucks and 2.3% in adult, hunter-harvested elk.

The WGFD released its 2024 CWD Surveillance Report this spring, stating that out of 5,276 samples of CWD tested, 726 came back positive.

The number of CWD submissions reported in 2024 were slightly higher from 2023’s 5,100 CWD submissions. In 2023, the percentage of mule deer bucks that tested positive for CWD was slightly lower at 18.9%. The percentages for white-tailed deer and elk decreased from 2023 at 30.3% and 2.8,% respectively. There were no positive CWD samples from moose.

The CWD Surveillance Report also states that in 2024, CWD was detected in three new deer hunt areas — 31, 53 and 94 — and three new elk hunt areas — 23, 84 and 126. Earlier this year, CWD was found in three additional elk hunt areas — 62, 87 and 93 —  and on four elk feedgrounds in western Wyoming.

The WGFD wrote on its website that throughout 2024, 95% of Wyoming’s mule deer hunt areas and 62% of elk hunt areas were considered endemic for CWD. The WGFD said that it will continue to conduct yearly surveillance focused on priority and mandatory areas. CWD levels are not uniform across a herd and can accumulate in hot spots of higher concentration within these herd units. In areas where the disease has not been detected, “CWD sampling is critical for early detection of the disease as management strategies can change with the status of CWD prevalence,” the WGFD wrote.   

“To determine CWD prevalence in individual herds, five-year averages were calculated to ensure a significant sample size,” the WGFD wrote. “The Project herd in the Lander Region continues to have the highest CWD prevalence in the state at 66.3%. The Shoshone River herd in the Cody Region is second at 47.6%.” 

The WGFD wrote in the announcement that CWD is a fatal disease of the central nervous system in mule deer, white-tailed deer, elk and moose. It belongs to the group of rare diseases called transmissible spongiform encephalopathies. These disorders are caused by abnormally folded proteins called prions. There is no cure or vaccine for CWD. There have been no cases of CWD in humans and no direct proof humans can get CWD. However, the Centers for Disease Control and the World Health Organization recommend not consuming CWD-positive animals.

All CWD testing is free for animals harvested in Wyoming.