CHEYENNE – The Wyoming Game and Fish Department’s Wildlife Health Laboratory tested 6,884 samples from big game animals for chronic wasting disease in 2021.

Testing was completed in early January, and samples were submitted from throughout the state. CWD was not detected in 6,045 samples and 831 samples were positive. Hank Edwards, Game and Fish Wildlife Health Laboratory supervisor, said those numbers are based on submissions from hunters, road-killed animals and animals found dead or in poor condition.

CWD is a chronic, 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. Early in the disease animals don’t show any clinical signs. Later on, affected animals show progressive weight loss, reluctance to move, excessive salivation, droopy ears, increased drinking and urinating, lethargy and eventually death.

The number of tested samples and positive tests increased for the third consecutive year. In 2020, 6,496 samples were tested with 829 positives compared to 5,067 samples tested and 568 positives in 2019. Edwards said comparing the number of positive tests each year can be misleading because the Game and Fish’s CWD surveillance program focuses on different deer and elk herd units each year, and the number of positive cases is proportional to the prevalence of CWD in the particular herd unit surveyed that year.

“That said, we can say the prevalence of CWD is slowly increasing in most deer and elk herd units in the state,” said Edwards, who added CWD was detected in four new deer hunt areas and five new elk hunt areas in 2021.

Edwards said the lab, which consists of five employees and two part-time workers, spent 1,788 hours — the equivalent of 74.5 days — conducting CWD testing. That doesn’t include surveillance preparation, data entry and writing reports once the testing season is over. Additionally, the lab continues to conduct brucellosis surveillance in hunter-killed elk, respiratory disease in bighorn sheep, as well as many other diseases of wildlife across the state.

The majority of the samples this year were collected by Game and Fish field personnel at hunter check stations or through regional offices. Edwards said the number of samples collected and submitted by hunters continues to increase each year.

“Chronic wasting disease is a major concern for Game and Fish and we sincerely thank all those who contributed samples from their deer, elk and moose,” Edward said. “These samples help us better understand the prevalence and distribution of this disease in our state.”

New for 2021, Game and Fish implemented mandatory sampling in deer hunt areas 96 and 97, as well as hosted a raffle for hunters who submitted CWD samples from targeted (tier I) and non-targeted (tier II) species and hunt areas. Both efforts increased interest in sampling and returns.