142 animals test positive for Chronic Wasting Disease

The 2019 sampling for chronic wasting disease began April 1 and ceased near the end of January. Among other results the testing yielded Montana’s first detection of the disease in moose and elk.

The Montana Department of Fish, Wildlife and Parks (FWP) submitted a total of 6,977 tissue samples from white-tailed deer, mule deer, moose and elk during the 2019-20 sampling season.

Of those samples, 142 animals tested positive for the fatal neurological disease. They included 86 white-tailed deer, 53 mule deer, two moose and one elk.

The news was especially grim in Libby.

FWP officials reported that 13 percent of hunter-killed or trapped white-tailed deer were positive for CWD, and 4 percent were positive outside of the city within the Libby CWD Management Zone.

A subcommittee of Libby’s city council is working to draft a wildlife management plan to cull some of the town’s urban deer. Biologists believe the concentration of deer in the city helps spread the disease.

Both of the two bull moose that tested positive for the disease were killed by hunters in the region. One was taken in late October near Pulpit Mountain, west of Quartz Creek and north of Troy. The other was killed near Fawn Creek southeast of Libby.

The wild cow elk that tested positive was killed in November on private land northeast of Red Lodge.

FWP’s priority sampling areas in 2019 included Libby and vicinity, southeastern Montana, the Philipsburg area and the Hi-Line.

Special CWD hunts, which required CWD testing of harvested deer, were held in the Libby and Moffat Bridge areas.

FWP offered free statewide testing to hunters who submitted their own samples.

Of the 6,977 total samples, 38 percent were collected from outside the priority sampling areas and about 15 percent were collected and submitted by hunters.

Since FWP’s renewed surveillance efforts in 2017, when CWD was first discovered in the wild in Montana, the agency has tested 11,020 samples statewide.

With the main sampling season over, FWP officials said the agency will review management strategies and other collected information to make plans for the next steps in managing the disease.

The agency said it will continue to collect samples from symptomatic animals throughout the year.

Separately, the Montana Department of Livestock reported January 31 that a single game farm elk in eastern Montana had tested positive for CWD. The disease had not been identified in domestic cervids in Montana since 1999, when it was found at an elk farm near Philipsburg. Those elk were killed on site and burned.

The Department of Livestock placed the herd in eastern Montana under quarantine and is conducting an epidemiological investigation.

Montana law requires that CWD positive game farm herds undergo complete depopulation and post-mortem herd testing or quarantine of the entire herd for a period of five years from the last CWD positive case.

“An epidemiologic investigation will be conducted, but at this time, the source of the disease is unknown,” said state veterinarian Dr. Marty Zaluski. “We will look at historical elk movements associated with this captive herd and proximity to infected wildlife to try to determine the source of exposure.”

CWD is a progressive, fatal disease that affects the nervous system of white-tailed deer, mule deer, elk and moose. Transmission can occur through direct contact between animals, urine, feces, saliva, blood and antler velvet.

Infected carcasses might serve as a source of environmental contamination and can infect other animals. Infected animals can carry the disease for years without showing signs of illness, but in later stages signs can include progressive weight loss, lack of coordination and physical debilitation.

There is no known transmission of CWD to humans. However, the Centers for Disease Control and Prevention recommends hunters who kill an animal in areas with a known CWD presence have their animal tested. If the animal tests positive, the CDC advises against eating the meat.