‘Silver lining’: CWD prevalence in North Idaho at less than 1%

An always-fatal disease did show up in deer in North Idaho last fall, but wildlife officials are feeling confident that the disease isn’t widespread.

After finding chronic wasting disease in a white-tailed deer outside of Bonners Ferry, the Idaho Department of Fish and Game ramped up sampling efforts in the area with a special surveillance hunt and mandatory testing within a larger management zone in Boundary County through the hunting season.

By the end of the hunting season, the agency had gathered 936 samples from the management zone, which covered all of Boundary County east of the Selkirk Crest.

Of those, six were positive for CWD. TJ Ross, an Idaho Fish and Game spokesman, said biologists estimated the disease’s prevalence in the zone at 0.33%.

That’s relatively low compared to other areas. In a portion of central Idaho, where the disease was first found in 2021, a dedicated deer cull found that 10% of the animals killed had the disease.

Ross said the low rate shows the disease was found early in the Panhandle, giving wildlife officials a chance to try to limit the spread.

“That’s the one silver lining,” Ross said.

Now their focus has turned toward using hunters to help stem the spread. In March, the Idaho Fish and Game Commission approved five new controlled hunts in the CWD management zone that amount to an additional 350 deer tags.

Additional hunting pressure will help biologists track the spread of CWD and help slow its spread to other elk and deer herds in the region.

Caused by deformed proteins, CWD attacks the nervous systems of deer, elk and moose. There have been no documented cases of CWD being transmitted to humans, but health officials recommend against eating the meat from infected animals.

The disease has been showing up in new places regularly. It has been found in 35 states. In places where it’s been present for years, researchers are seeing declines in big game populations.

Washington detected its first case of the disease last summer in a deer in north Spokane. During the hunting season, more deer from the same area tested positive, as did one in southern Pend Oreille County.

The Washington Department of Fish and Wildlife does not have an estimated prevalence rate, as biologists continue collecting samples through the end of the month. Hunter Westacott, a WDFW biologist, said the agency expects to release its annual CWD report in late July.

Idaho has found the disease in three areas. The detection in 2021 came in the Slate Creek drainage near White Bird. It has also been found near New Meadows.

The Panhandle joined the fray last July, when a deer found dead within 3 miles of Bonners Ferry tested positive. A surveillance hunt was held in that area in August, which turned up two more cases.

During the hunting season, mandatory CWD testing was ordered for the portion of Game Management Unit 1 that’s within Boundary County and east of the Selkirk Crest.

That effort was responsible for three more positive tests.

In a news release, Idaho Fish and Game officials wrote that Unit 1 is popular with white-tailed deer hunters. More than 7,000 hunters targeted white-tails there in 2023, and they managed to kill 2,900 deer.

The new hunts mean an additional 100 antlered deer tags and 250 antlerless tags will be available to hunters this fall.

Testing for hunter-killed mule and white-tailed deer will still be mandatory in the management zone. Samples usually consist of lymph nodes or brain tissue, which can only be gathered from dead animals.

That makes hunters key in long-term efforts to fight the disease, Ross said.