ELAND — It’s been almost five months since a prize buck on a game farm in eastern Marathon County tested positive for chronic wasting disease, and investigators are as befuddled about the case today as they were in November.

The game farm, Wilderness Whitetails, and its affiliated breeding farm in Portage County have followed all of the protocols set forth by the Wisconsin Department of Agriculture, Trade and Consumer Protection intended to prevent the spread of the deadly disease. Wilderness Whitetails is a 351-acre, family-run hunting ranch that started business 37 years ago, owner Greg Flees said in December. The disease was found in a routine test after a hunter killed the animal.

The herd had been “closed” for more than a decade, Flees said, meaning that no deer had been brought into the operations from the outside. The breeding farm is double-fenced, which keeps wild deer from getting close to the captive animals to prevent the spread of chronic wasting disease, but the hunting preserve is not, in accordance with state regulations.

No deer had tested positive on the preserve before; it was the first new CWD-infected deer tested on any Wisconsin farm since October 2008, and the farthest north a captive deer had been found to have the disease. The infected buck was one of the preserve’s 270 deer, game for people who pay for the right to hunt them.

Flees cooperated fully with the investigation of how the buck got sick, said Paul McGraw, state veterinarian. But even with Flees’ help and subsequent investigative efforts, McGraw said he doesn’t think there ever will be an answer as to how that buck got sick — which leaves hunters in eastern Marathon County nervous.

“This guy has got a real good record,” McGraw said. “This particular farm has done a lot (to prevent CWD exposure). There’s a low risk that CWD is in the breeding herd.”

The case underscores just how little is known about CWD, and the knowledge gap makes it difficult to manage the disease.

“There’s not been a lot of research done on it,” McGraw said. “And there are not a lot of good answers.”

CWD upswing

The Wilderness Whitetails case comes at a time when the disease continues to run rampant among wild deer in Iowa County and western Dane County, where the state Department of Natural Resources says that one in four adult male deer has the fatal disease. The prevalence rate of 25 percent is based on 2013 test results from that deer management zone. The rate has more than doubled since 2002, when 8 percent to 10 percent of bucks had the disease.

The CWD stakes are high in a state that places a premium on hunting socially, culturally and economically. In 2010, deer hunting licenses and permits generated $22.7 million for the DNR, according to PolitiFact Wisconsin. Estimates of the overall economic impact to the state as a whole exceed $1 billion.

CWD affects elk and moose as well as deer, according to the U.S. Department of Agriculture. It was first recognized in 1967 and belongs to a family of diseases called transmissible spongiform encephalopathies. Other TSEs include bovine spongiform encephalopathy in cattle, scrapie in sheep and goats and Creutzfeldt-Jacob disease in humans. CWD, though, is distinct from those other diseases, the USDA said.

The growth of CWD in southern Wisconsin, coupled with the Wilderness Whitetails case, is troubling, said Marcell Wieloch, 71, of Mosinee, a longtime deer hunter with gun and bow.

“The elephant in the room, the fear that some people have, is if they shoot that deer, and eat that deer, sooner or later it’s going to transfer to Creutzfeldt-Jacob disease,” Wieloch said. “You start bringing those threads together.”

No one understands specific causes of CWD. Most scientists believe, however, that TSE diseases are caused by proteins called prions. And scientists agree that CWD often is transmitted directly from one animal to another through saliva, feces and urine containing abnormal prions, according to the USDA.

Records show the buck killed at Wilderness Whitetails never came in contact with another infected deer, so it’s a mystery as to how it contracted CWD. Three possibilities include that the buck got the disease spontaneously; that it came from exposure in the herd of the hunting preserve or breeding farm; or that it picked up the disease in the environment, McGraw said.

“We don’t know if there are prions in the soil, whether it can survive a while in the environment,” McGraw said. “We don’t see any scientific way of naming any one of these possibilities as the reason (the Wilderness Whitetails buck had the disease.)”

Unknown future

The state DNR, which oversees CWD policy among wild deer, uses one main tool to quash the disease. It prohibits deer baiting and feeding in areas where CWD has been found in deer. Marathon County already was under the restriction because farm deer in Portage County had been tested as CWD positive. The Wilderness Whitetail case extended the region to Shawano and Waupaca counties, said Tami Ryan, chief of the DNR’s wildlife health program.

The DNR also will step up its surveillance for CWD in the area to get a better idea how prevalent the disease is.

“There is no CWD in the wild deer in Marathon County, as far as we know,” Ryan said.

Did finding CWD in a captive herd increase the potential for the disease to spread to wild deer? It’s a concern, Ryan said, but there is no way to know.

Wieloch would like to see the DNR take a more aggressive stance against CWD. Other states, such as Colorado, he said, have helped limit its spread by using sharpshooters to kill deer in CWD zones.

Ryan said one reason the DNR hasn’t taken more drastic steps is because of the public and hunters as a whole, have opposed those measures.

“We respond by social influence and outlook, attitude and opinion,” Ryan said. “The tide is shifting a little bit. Based on our past experience, we’re seeing more public sentiment that wishes we were doing more, taking a stronger stance.”