Town deer tests show improvement

The number of tests coming back positive for chronic wasting disease is holding steady, according to the latest data from the Wyoming Game & Fish Department.

Crook County’s deer hunt areas were on the high priority list for testing in 2023, along with a large portion of the west of the state and several to the south and center.

Hunters in high priority areas are asked to submit samples for testing to help the department monitor the spread of the always-fatal disease.

From those areas, and from all across the state, a total of 5100 samples from big game animals returned 711 positive results. The majority of samples came from harvested game and were submitted to field personnel at hunter check stations and regional offices, but some also came from road-killed animals and animals that were found dead or were euthanized.

That’s an overall statewide rate of 13.9%, which is similar to the 14.1% recorded the year before and a little higher than the 12.2% in 2022.

According to figures provided by Game Warden Nate Holst, however, the Black Hills area is currently faring a little better than the statewide figures.

During the years 2021 to 2023, 7.5% of hunter-harvested adult male deer from the Black Hills Herd Unit returned a positive result. For yearling males, the figure was 8.7%, and for adult females, it was 8.3%.

CWD has been a cause for concern in this area over the last year or so, leading to Game & Fish suggesting a longer culling season around Sundance last year with a higher-than-usual quota.

The operation saw 26 white-tailed deer harvested within city limits, only two of which tested positive. This represents a 7.7% prevalence rate.

That’s a big improvement on the year before, when seven of the 50 tested returned a positive result, putting the Sundance area at a 14% prevalence rate.

According to wildlife disease specialist Jessica Jenings-Gaines, it’s difficult to draw conclusions from the year-to-year rates because the surveillance program switches between deer and elk her units each year.

However, she said, “We can say that the prevalence of CWD is slowly increasing in many deer and elk herd units in the state. In 2023, CWD was detected in three new deer hunt areas and Yellowstone National Park and four new elk hunt areas.”

Every mule deer hunt area in the northeast of Wyoming is now known to be positive for CWD, along with elk hunt areas 1, 117 and 129.

CWD, sometimes called “zombie deer disease” affects deer, elk, reindeer and moose and is caused by abnormally folded proteins called “prions”. These cause damage to normal prion proteins in tissues throughout the animal’s body, but most often in the brain and spinal cord.

Deer and elk are unlikely to display symptoms at first, because the incubation period can be anything from 18 to 24 months. However, the advanced stages of CWD can cause droopy ears, a lack of energy, a lack of gloss to the coat and lethargy, as well as emaciation in extreme cases; the disease is always fatal and there are no known treatments or vaccines.

Even today, CWD is not fully understood. Studies are ongoing and will likely take many years, largely because it takes a long time for symptoms of disease to appear.

Scientists believe the proteins probably spread through bodily fluids, either directly or through contamination of soil, food or water. It can spread quickly and the prions remain in the environment for a long time, so other animals can still contract it even after an infected animal has died.

“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.”