CWD Detected in Ruby Mountains and Flathead Valley

Wildlife managers recently detected chronic wasting disease in an elk in the Ruby Mountains and a deer in the Flathead Valley, marking firsts for each area. The detection in the Flathead is significant—it is the first case there—while the infection in the Ruby Valley is the first elk to test positive in that region.

According to Montana Fish, Wildlife and Parks, the fatal and highly contagious neurological disease affecting deer, elk and other cervids was discovered in 1967 in mule deer at a research facility in Colorado. As of 2023, CWD has been found in captive and wild cervids in 35 states, five Canadian provinces, Norway, Sweden, Finland, and South Korea. Yellowstone National Park saw its first case in October 2023 when a mule deer carcass tested positive.

According to a Nov. 1 FWP press release, a hunter harvested the CWD-infected elk adjacent to the lower Ruby Valley. This was the first detection of CWD in elk in this area, however there has been a high prevalence of white-tailed and mule deer infections. The agency continues to sample hunter-harvested animals in the region, and results indicate that the prevalence of the disease in elk likely remains low at this time.  

Just days before general hunting season opened on Oct. 26, wildlife officials also confirmed the disease in a symptomatic buck wandering around the Flathead County Landfill. Dillon Tabish, FWP’s information and education specialist for the region, told Mountain Journal this is the first time they’ve detected CWD in wild deer in the Flathead area known as HD 170.

The main signs of CWD are sickly, stumbling and drooling animals with drooping head and ears. “It looks kind of like the name implies, Tabish said. “Like [the infected animal] is slowly wasting away,” said Tabish. “[CWD] is a slow-moving disease that can take even a couple of years for a symptomatic deer to show those symptoms.”

Ongoing research suggests predators may play an important role in keeping CWD under control. Results from a study published in the Journal of Animal Ecology suggest that “under moderate, yet realistic, predation pressure from cougars and wolves independently, predators may decrease CWD outbreak size substantially and delay the accumulation of symptomatic deer and elk.”

Tabish said hunting is the agency’s primary tool for monitoring and managing CWD. “Looking at other states that have been in this for a long time, the best you can do is hope to contain and control the spread. There’s not any evidence that you can eradicate it once it infects an area and a herd.”

In the Flathead, FWP is encouraging increased hunting harvest in the area by increasing the number of 170-00 Deer B tags for individual hunters from one to two. “Hopefully this will help us get more samples and provide a better picture of how bad it is,” Tabish said. Reducing the size of the herd in the targeted area will also help reduce the spread of the disease to other herds, he added.

The agency said in its press release that it’s unlikely that the detection of CWD in the Ruby Valley elk will result in changes to elk hunting regulations in the area, which already has liberal harvest regulations for elk.

Aside from a few exceptions, like in Libby, Montana, where testing for CWD in harvested cervids is currently mandated, testing is optional throughout Montana. FWP is urging hunters to test animals and help provide important data.

Testing for CWD is free, and hunters can take the samples themselves or bring the harvested animal to an FWP regional office or a CWD sampling station. Specific instructions can be found on the agency’s website.

While there is no evidence that CWD is transmissible to humans, the Centers for Disease Control and Prevention advises against consuming meat from an infected animal.

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