Focus turns to understanding scope of chronic wasting disease outbreak in area deer

It’s not clear how a deer in north Spokane ended up with chronic wasting disease, but wildlife officials believe they found the disease early and are prepared to deal with it.

They also think there are more cases out there. Now, their focus turns toward understanding the scope of the outbreak.

“It’s probably safe to assume that there are other animals infected,” said Donny Martorello, chief of the Washington Department of Fish and Wildlife’s wildlife science division.

Martorello spoke at a virtual news conference alongside a handful of other government officials on Monday, a few days after WDFW announced it had confirmed the state’s first case of the always-fatal condition affecting moose, elk and deer. The disease was detected in a white-tailed deer found dead in the Fairwood area.

Officials will meet this week to work out details such as where WDFW will focus testing efforts, how it will get the samples they need and what measures may be needed to contain the outbreak.

“We’ve been preparing for a detection in Washington state for a number of years,” Martorello said. “… We were all hoping this day would be much farther away, but here we are.”

Chronic wasting disease is caused by abnormal versions of microscopic proteins called prions. A deformed prion causes others to misfold, and over time the disease attacks an animal’s nervous system, leading to its death.

There is no evidence the disease can infect humans, but health officials advise against eating meat from infected animals. In animals, it advances slowly, and symptoms such as emaciation or erratic behavior don’t become apparent until the late stages of the disease.

Animals pass the disease to one another through bodily fluids, and the prions can persist in soil for a long time. Left unchecked, the disease can wreak havoc on wildlife populations.

“We know from other states that it does have population impacts, and you do see a decline in those populations,” said Melia DeVivo, an ungulate research scientist for WDFW.

Last week’s announcement made Washington the 35th state to discover the disease. The state has been looking for it for years and ramped up its testing program in 2021 after Idaho confirmed its first case.

Test samples come only from dead animals. The state relies on hunters submitting tissue or lymph nodes from animals they have killed and also collects samples from roadkill or other animals they happen upon.

A landowner found the deer that tested positive on their private property in February and reported the carcass to WDFW.

At the time, DeVivo said there was no indication of chronic wasting disease, but that the agency gathered a sample because it was within the area where the agency has been looking for the disease.

The sample was not tested until July. The Washington Animal Disease Diagnostic Lab, which conducts the tests, accepts samples in batches of 90, so WDFW had to wait until it had enough samples to ship to the lab.

Other animals from the area have been tested in the past and turned up negative. Using that data, DeVivo said their best guess is that 2% to 3% of the deer in the population could have the disease, but that they need to “sample rigorously” to produce a more accurate estimate.

That is what the department will do over the next several months.

First, WDFW will define the area where it plans tofocus testing. The agency’s chronic wasting disease management plan calls for an area with a radius of 10 miles, but officials said Monday that will likely be expanded.

The deer that tested positive was in a residential area where hunting isn’t allowed, which eliminates the state’s preferred method for gathering samples. Expanding the radius could include some areas where deer are hunted.

Other options such as a WDFW-directed deer cull are on the table, but no decisions have been made.

“This one is going to be a bit more challenging, and we haven’t gotten to the point yet of making decisions around that,” Martorello said.

Restrictions on transporting deer and elk carcasses may be put in place to limit the human-assisted spread of the disease. The management plan calls for establishing a transport restriction zone that’s larger than the response area.

Under the plan, hunters would not be allowed to take carcasses out of the zone. They would be able to move boned-out meat, skulls and antlers with no soft tissue attached, hides or capes without heads, and finished taxidermy mounts.