Idaho Fish and Game officials said Wednesday that two mule deer bucks killed in the Slate Creek drainage near Lucile tested positive for chronic wasting disease — a contagious and fatal neurological disorder that had not previously been detected in the state.

According to a news release from the agency, the deer were shot last month in Unit 14 and the hunters, who had submitted lymph nodes from the animals as part of a voluntary CWD monitoring program, have been notified of the results.

The disease can also infect elk, moose and caribou and had previously been confirmed in 25 states. It has slowly been making its way to Idaho in a westward march through ungulate populations. It was documented in wild deer in Colorado in 1981 and Wyoming in 1985. The first case in Montana was detected in 2017.

Toby Boudreau, chief of the Fish and Game’s Wildlife Bureau at Boise, said the two deer were killed about one-quarter mile from each other. He was “very surprised” Idaho’s first positive tests came from an interior unit and not from one bordering Montana, Wyoming or Utah — states that have known cases of the disease.

Earlier this year, the agency determined it needed more samples from Unit 14 that stretches from Riggins to Cottonwood and asked hunters to help collect them. Letters with detailed instructions and sample bags were mailed to hunters who drew controlled mule deer permits in the area asking them to submit lymph node samples if their hunt was successful.

“The two positives we have detected to date were both hunter-taken samples, which is awesome,” Boudreau said. “We sent them out, hunters were interested and engaged enough to learn how to do it, and then took the right samples and got them back to us in time and it worked perfectly.”

The state’s CWD monitoring program is designed to detect a 1 percent prevalence of the disease 95 percent of the time. Boudreau said the agency’s CWD team is analyzing possible next steps and will quickly establish a CWD management zone in the area, determine if more sampling is needed, how they might be collected and look at known animal migration patterns in the unit. The information will be used to craft management options that are likely to be presented to the Idaho Fish and Game Commission for consideration in the near future.

“Our strategy sort of focuses on trying to keep the prevalence as low as possible,” he said. “When we keep the prevalence low, we can slow the spread of it.”

One tool that could be used is hunting. Some states have implemented special hunts in response to new CWD detections. For example, Montana offered 600 tags in 2019 for a special hunt in a limited geographic area designed to test for the disease and slow its spread.

Idaho Fish and Game officials have previously said it was likely only a matter of time before the disease was detected in Idaho. Just this year, the agency updated its CWD response plan.

Symptoms of the disease include excessive salivation, drooping head/ears, tremors, extremely low body weight and unusual behavior, such as showing no fear of humans and lack of coordination. It is caused by misfolded proteins known as prions and is from a family of diseases known as transmissible spongiform encephalopathies.

Boudreau said the agency does not make recommendations to hunters about the safety of consuming meat from animals that have the disease and instead directs them to the Centers for Disease Control and Prevention. Information posted to the federal agency’s website says the disease has never been detected in humans and it is not known if humans can contract it. It recommends that people who hunt in areas where the disease is known to be prevalent have their animals tested before consuming meat from them and to not eat the meat from animals that test positive.

The lymph nodes are required to detect the disease. Boudreau said Fish and Game is seeking more samples from Unit 14 but will test animals taken in other units. More information on the disease, including how to submit samples, is available at idfg.idaho.gov/cwd/plan.

Barker may be contacted at ebarker@lmtribune.com or at (208) 848-2273. Follow him on Twitter @ezebarker.