The Wyoming Game and Fish Department’s Wildlife Health Laboratory tested 6,701 samples from big game animals for chronic wasting disease (CWD) in 2022. Testing was completed earlier this year and samples were submitted from throughout the state. CWD was not detected in 5,875 samples and 826 samples were positive. Some samples submitted were not testable.
Jessica Jennings-Gaines, Game and Fish wildlife disease specialist, 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 urination, lethargy and eventually death.
The number of tested samples and positive tests have remained steady for the past three years. In 2021, 6,884 samples were tested with 839 positives and in 2020, 6,496 samples were tested with 829 positives.
However, Jennings-Gaines noted that comparing the number of positive tests each year can be misleading because Game and Fish’s CWD surveillance program focuses on different deer and elk herd units each year. Additionally, the number of positives is proportional to the prevalence of CWD in the particular herd unit surveyed.
“We can say that the prevalence of CWD is slowly increasing in many deer and elk herd units in the state,” Jennings-Gaines said. “The western half of Wyoming has several deer hunt areas where CWD has not been detected, however the disease continues to spread west and was detected in two new deer and five new elk hunt areas last year.”
Jennings-Gaines said the lab, which consists of four employees and three contract employees, spent the majority of the 2022 hunting season conducting CWD testing with peak testing occurring between October and November. That doesn’t include surveillance preparation, data entry and writing reports once the testing season is over.
The majority of the test samples this year were collected by Game and Fish field personnel at hunter check stations or through regional offices.
“Chronic wasting disease is a major concern for Game and Fish and we thank hunters who contributed samples from their deer, elk and moose,” Jennings-Gaines said. “These samples are instrumental in helping us better understand the prevalence and distribution of this disease in our state.”