Central Idaho deer cull shows 10% of animals had CWD

LEWISTON – The Idaho Department of Fish and Game’s latest effort to cull deer numbers in the state’s chronic wasting disease hot spot showed 10% of the removed animals suffered from the deadly ailment.

J.J. Teare, supervisor of the agency’s Clearwater Region, said the CWD prevalence rate in Game Management Unit 14, a much larger geographic area, is estimated to be 1.4% for white-tail deer. Not enough mule deer have tested positive for the disease to establish a unitwide prevalence rate among that population. The estimate for Unit 14 was compiled by testing hunter-killed deer there and testing roadkilled and other dead deer. Teare said it remains low.

“We are 95% confident it’s less than 2%,” he said.

In February, the agency killed 155 deer and two elk during a three-week project aimed at thinning deer densities in lower Slate Creek and the nearby McKenzie and John Day creek drainages near White Bird. The two elk were killed because they were visibly sick. One of them tested positive for CWD along with 12 white-tail deer and three mule deer.

“We know Slate Creek is still a hot spot. We are sitting about 10% of the animals we removed with the control action testing positive for CWD, which is substantial,” Teare said. “It’s a good thing we are still in there trying to keep that density down.”

Of note: Two deer removed from Unit 18, which is across the Salmon River from Slate Creek, tested positive, marking the first time the disease has been detected there.

“We know the river is not a barrier,” Teare said. “It wasn’t a surprise, but it means we really have to start looking at 18 and start monitoring it more closely.”

Chronic wasting disease was discovered in the Slate Creek Drainage three years ago, marking the first time the disease had been documented in Idaho. It has since been documented near New Meadows and is present in 32 states and five Canadian provinces.

The disease is spread when infected animals shed misfolded proteins known as prions. Scientists believe that most often occurs from nose-to-nose contact between animals. But the prions persist for years on the landscape and can serve as an infection source. The disease cannot be eradicated.

Instead, the department is attempting to contain it or slow its spread.

To do that, it has carried control actions over the past two winters where deer within the hot spot are baited and then killed. The meat from animals that test negative are donated to food banks or directly to people in need.

The department has also liberalized deer and elk hunting regulations in the area and established a CWD management zone with special regulations, including mandatory testing of hunter-killed deer and elk and a requirement that hunters bone-out the meat from animals but leave the rest of the carcass.

Idaho Fish and Game recently made some changes to the zone. Unit 15 was removed from the zone and Unit 18 was added.

That means hunters in Unit 18 will be required to have their kills tested for CWD and those in Unit 15 no longer need to do so. The department will continue to encourage voluntary testing in Unit 15.

Units 23, 24 and 32A, near New Meadows are also under mandatory CWD testing regulations. Last year a deer killed near New Meadows tested positive for CWD.