'Like a prion bomb': Chronic wasting disease mystery hits near La Crescent

Like most archery season deer hunters, Craig Ihrke values his solitude in the woods. For him, above all, it's an opportunity to sit, listen, watch and absorb the natural world.

These days, because of mysterious circumstances, he wonders if his children and potential grandchildren will develop the same appreciation for the hunt. The 90 acres of Driftless Area bluff land near La Crescent he owns with his brother Bill has inexplicably become an island of chronic wasting disease (CWD).

Over the past three hunting seasons, five whitetails harvested by the family or found dead on the property have tested positive for the always-fatal neurological disease spread by prions. They are the only wild deer confirmed with CWD in all of Houston County and state wildlife researchers have not detected any other cases within a 5-mile radius of the Ihrke parcel. Sampling for the disease in that circle has included 900 hunter-harvested, road-killed or sharpshooter-killed deer.

"This one is a head-scratcher," said Michelle Carstensen, wildlife research supervisor for the Department of Natural Resources. "We have no real explanation as to why. It's like a prion bomb exploded there."

The Ihrkes have welcomed the DNR's inquiries into the strange cluster of cases located east of the tiny village of Money Creek and west of La Crescent. It's in the heart of some of the best whitetail habitat in the state. They bought the land for hunting about 15 years ago and have no knowledge of anyone ever using it as a disposal site for deer carcasses.

Any previous dumping of dead deer — if they were laden with CWD prions — would provide one possible explanation for a hot spot. That is because the abnormal, infectious proteins can persist for years in the soil and other surfaces.

Craig Ihrke said DNR's wildlife biologists also have looked at a pond on the property, old salt deposits, and depressions where water collects. All of those places are potential gathering places for deer, and the animals can spread the disease among themselves when they closely congregate. But none of those locations has been flagged as trouble spots.

Eight to 9 miles north of the Ihrkes' land is a defunct, previously infected deer farm strongly linked to an outbreak of CWD in wild deer south of Winona. But several years of CWD surveillance in the area hasn't connected any dots from the farm to the Ihrke cluster.

"They are baffled by it," Ihrke said of the DNR. "We've told them: 'Whatever you want to do on our land, do it.' "

The repeated findings of infected deer have not stopped the Ihrke clan from hunting. This season, nine friends and family members combined to harvest seven deer. One of those was a monster buck that Craig will hang on the wall of his Chatfield home. An eighth deer — the one that tested positive this season — was a young doe that Craig found dead during the archery hunt. It was in poor body condition and he summoned the DNR to sample it.

Ihrke said the biggest loss caused by the cluster of CWD has been the enjoyment his clan gets from butchering and eating the venison.

In 2018, the Ihrkes had their deer tested for CWD in cooperation with regional surveillance provided by the DNR. While the tests were pending, they butchered like they always have — gathering in Bill's garage in Plainview. They socialized over a few beers while running their traditional assembly line of cutting and packaging.

All the meat was in refrigerators when Craig's 16-year-old son, Luke, was notified that his buck had tested positive. In keeping with human health advice from the Centers for Disease Control and Prevention, they decided not to consume any of the venison. It was their first brush with CWD, and they hadn't separated the deer. They also used the same utensils for all the cutting, potentially spreading prions. The families voluntarily handed over all the meat from 11 deer to the DNR for safe disposal.

"None of us want to take a chance" of eating tainted meat, Ihrke said.

The group's new norm — cemented this year by social distancing complications of COVID-19 — has been for each family to handle their own deer.

"The whole thing is kind of wrecked now because half the fun was getting together to butcher," Ihrke said.

The CWD mystery isn't enough for the Ihrkes to give up their land. But Craig Ihrke said he worries that the departure from normalcy and tradition will dampen the enthusiasm for deer hunting in his own children, just as it was taking root.

"It's the best deer hunting in the state, probably," he said. "I sure would like to see my grandkids shoot deer and enjoy it like I did."

Tony Kennedy • 612-673-4213