Chronic wasting disease surveillance underway in central Idaho 

by Logan Finney, Idaho Reports

courtesy USGS

The arrival of a fatal neurological condition has Idaho Fish and Game officials concerned, but it’s not the only challenge facing Idaho’s deer and elk populations.

The illness known as chronic wasting disease was detected this October in two mule deer in central Idaho. The samples were the first positive CWD cases since the state began testing for the disease in 1997, according to Idaho Fish and Game.

Similar to mad cow disease, chronic wasting disease is a neurological disorder caused by a prion – or pathogenic, misfolded protein – that affects the brain and nervous system of deer, elk, moose and caribou. Unlike mad cow disease, however, it is believed that CWD does not have a form transmissible to humans

According to the CDC, there have been no reported cases of CWD infection in people to date. It has been detected in wild and domestic cervids – the deer family – in more than half of the states, parts of Canada, Scandinavia and South Korea. 

While the CWD prion has now been detected in Idaho, the disease hasn’t yet had an effect on the state’s wildlife population.

“We do not have CWD manifesting itself as a disease. We have detected it in two animals,” Idaho Fish and Game Director Ed Schriever told Idaho Reports on Friday. “We literally found the needle in the haystack.” 

On the other hand, Schriever told Idaho Reports, thousands of white-tailed deer in north-central Idaho have died this year due to epizootic hemorrhagic disease. That illness is caused by a virus that is spread by biting gnats that breed in pools of stagnant water, and is especially prevalent during drought years. 

The disease affects only white-tailed deer, not mule deer, and has a high fatality rate. EHD has struck the state before, Schriever said, and 2021 was the second worst EHD mortality occurrence in Idaho.

CWD Map Showing GMU and County | courtesy Idaho Fish and Game

The two CWD-positive Idaho deer were harvested in Game Management Unit 14 in the Slate Creek area near Lucille, between the towns of Riggins and White Bird in Idaho County. 

“We are a bit surprised to find our first positive [CWD] sample in Unit 14 – on the west side of the state – when we know we have it to the south in Utah and to the east in Wyoming and Montana,” Schriever told Idaho Reports.

Fish and Game has collected negative test samples from roughly twenty thousand deer and elk around the state over decades of monitoring chronic wasting disease. 

On Nov. 22, the Idaho Fish and Game Commission approved a series of emergency hunts in central Idaho to help determine the prevalence of the disease, now that it’s been detected. 

“These hunts were set strictly to get more samples for CWD testing,” Schriever said in a Dec. 2 press release. “The intent is not to reduce deer densities in response to CWD, it’s strictly to understand what we’re dealing with.” 

Idaho Fish and Game is offering 1,527 deer tags for the specialized hunts to collect 775 samples for CWD testing. The hunts are limited to Idaho residents and will end when Fish and Game has gathered enough samples. 

CWD Surveillance Hunt Area Overview | courtesy Idaho Fish and Game

The $10 tags are available only at Fish and Game regional offices, and they come with strict requirements. Hunters are allowed to keep the meat and antlers of the deer they harvest, but must record the geographic coordinates of the kill site, quarter or debone the animal at the site and present the head to a regional office or CWD check station within 24 hours.

The Lewiston Tribune reports that almost all of the tags for public land hunts sold out on Tuesday, while more tags for private land hunts are available to hunt area landowners and the hunters they designate. 

The various hunts are scheduled to close Dec. 19, but that date could change based on the number of samples collected. IDFG will notify hunters via phone or email 48 hours before closing a hunt. 

Schriever told Idaho Reports that IDFG has already collected more than 300 samples from deer and elk that were harvested in the surveillance area earlier this year during open season. Of those samples, 68 are still pending.

“We will only take additional animals up to the numbers we need for sampling,” Schriever said in November. “We’re going to take the minimum number that is needed to be able to make good decisions.” 

IDFG encourages all hunters to contact any regional office for CWD testing, especially for animals harvested from an area where CWD has been found. 

Chronic wasting disease was first discovered in northern Colorado in 1967 and diagnosed in 1978. This year the disorder has spread to wider areas in Wyoming wild herds and in Texas private breeding operations. The arrival of CWD in Idaho has also raised concern for neighboring wildlife agencies in Oregon and  Washington

The WHO and CDC have concluded that there is currently no evidence that CWD can be transmitted from cervids to humans. However, those organizations still advise caution and IDFG recommends precautionary measures such as:

  • using rubber or latex gloves during field dressing
  • minimizing handling of brain, spinal cord, eyes, or lymph nodes
  • boning out harvested animals to remove the organs most likely to contain prions 
  • not eating or feeding the brain or spinal cord of wild cervids to other animals 

With the information gathered from these surveillance hunts, the next step for the Fish and Game Commission will be to establish a Permanent CWD Management Zone. 

State regulations prohibit the public from feeding deer and elk in designated CWD management zones, and hunters will be prohibited from transporting the head and spine of harvested animals out of the zone.

On Wednesday, the Lewiston Tribune reports, the U.S. House of Representatives passed the Chronic Wasting Disease Research and Management Act on a 393-33 vote. The legislation directs the U.S. Department of Agriculture to establish a CWD research and management program and would commit $70 million annually to fighting the disease. The bill now moves to the U.S. Senate. 

Visit Idaho Fish and Game’s website at idfg.idaho.gov/cwd for more information on chronic wasting disease in Idaho. 

We have more with IDFG Director Ed Schriever on this week’s episode of Idaho Reports, Friday at 8 p.m. on Idaho Public Television. You can also watch online at idahoptv.org/idahoreports or through the PBS app. 


<strong>Logan Finney</strong> | Associate Producer
Logan Finney | Associate Producer

Logan Finney is a North Idaho native with a passion for media production and boring government meetings. He grew up skiing, hunting and hiking in the mountains of Bonner County and has maintained a lifelong interest in the state’s geography, history and politics. Logan joined the Idaho Reports team in 2020 as a legislative session intern and stayed to cover the COVID-19 pandemic. He was hired as an associate producer in 2021 and they haven’t been able to get rid of him since. 

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