Monitoring intensifies to detect chronic wasting disease

by Mike Koshrml/Jackson Hole News & Guide | JANUARY 2, 2017

The intensity of the search for chronic wasting disease about doubled this year in Jackson Hole and more tissue samples were extracted from hunter-killed animals than ever before.

A grant from the Teton Conservation District and money chipped in by the Wyoming Game and Fish Commission enabled wildlife managers to increase staffing and test 502 animals from the Jackson Elk Herd — about 5 percent of the total population.

“Based on the records that I have that go back to 1997, this is the highest number of samples that we’ve ever collected both in deer and elk,” Game and Fish Brucellosis-Feedground Habitat Biologist Ben Wise said.

On average over the last five years about 275 chronic wasting disease samples were collected in Game and Fish’s Jackson Region.

Typically, two technicians are brought on seasonally by the state and the National Elk Refuge to work with hunters, outfitters and meat processors to collect tissue samples from elk. This year Game and Fish hired three techs and the Elk Refuge its usual one, doubling the manpower surveying for chronic wasting disease, Wise said.

Chronic wasting disease is spread by a horror-movie-like prion that can live for years in soil, be absorbed into grass, survive high heat and freezing temperatures and be exceedingly difficult to remove from an environment. It’s incurable, degenerative and invariably fatal in the elk, deer, moose and caribou it infects and causes to wither or “waste” away.

Wasting disease has been detected only twice in the Jackson Region, although never in elk, and both times in Star Valley. In 2008, it was discovered in a moose and in 2015 it was found in a mule deer. The malady is, however, spreading steadily toward the Continental Divide on the east side of Jackson Hole. This year for the first time it was discovered in mule deer immediately adjacent to Yellowstone National Park west of Cody and also just north of Dubois.

The impetus for the increased surveillance was a recently revised chronic wasting disease management plan for Wyoming that called for boosting sampling around the feedgrounds, which tightly quarter animals and spread disease.

Late-season elk hunts in Grand Teton National Park and on the National Elk Refuge have been the source of most of the samples collected. But Game and Fish’s technicians, who are aided by year-round staff that also sample, have stepped up monitoring on the east side of the range used by the Jackson Elk Herd, nearer the leading edge of the disease.

“We put more emphasis in sampling out of the Teton and Gros Ventre wilderness areas,” Wise said. “But it’s difficult because animals are spread out at the time of those hunts.”

Wise encouraged hunters to seek training at Game and Fish’s Jackson office on how to extract the retropharyngeal node from the throat area of an animal. More backcountry hunters turning in tissue samples, he said, would give Game and Fish better geographic reach in its surveying effort.

The samples turned in by hunters take about three weeks to test.

No human is ever known to have contracted chronic wasting disease, but public health officials do not advise consuming meat from animals that are infected with CWD. Laboratory tests have found that there’s not a complete species barrier, and mice have been able to contract the disease when infectious prions have been injected into their brains.