Elk winter feedgrounds in western Wyoming should be phased out to curb the potential spread of Chronic Wasting Disease in elk.

That is what Lloyd Dorsey of the Greater Yellowstone Coalition in Jackson recommends, using information he gathered from Wyoming Game & Fish Department reports.

Chronic wasting disease, or CWD, has been detected 40 miles from Yellowstone National Park and 45 miles from winter elk feedgrounds, according to a coalition map. Chronic wasting disease is a fatal disease of the central nervous system of deer, Rocky Mountain elk and (rarely) moose, according to the Game & Fish.

The 2012 department information reveals the farthest western advance of CWD positive deer in Wyoming yet, according to a coalition news release.

The disease occurs at a higher rate in deer areas than elk areas. Chronic wasting disease might arrive in feedgrounds, but it hasn’t so far, and they can’t predict whether it will, said Game & Fish information specialist Al Langston in Cheyenne.

But other experts sounded a warning.

“Finally, our results demonstrate that high-density elk populations (10 to 100 elk per kilometer squared) can support relatively high rates of CWD (.10 percent prevalence) that may substantially affect the dynamics of such populations,” stated an 2013 article by Ryan J. Monello and associates in “The Journal of Wildlife Diseases.”

“The good news is that the disease has not been detected at the feedgrounds or national parks yet,” said Bruce Smith, a retired U.S. Fish and Wildlife Service biologist and former biologist at the National Elk Refuge in Jackson. “Managers can still act to responsibly phase out winter feeding of elk and limit the effects of this and other diseases.”

Game & Fish staffers search for the disease by collecting and analyzing wild ungulate lymph nodes, mostly from animals harvested by hunters.

Testing is very reliable using lymph nodes. Analyzing live animal samples is not as accurate, Langston said.

A total of 2,017 deer, elk and moose samples were examined in 2012. Of those samples, 98 tested positive for CWD, including 78 mule deer, six white-tailed deer and 14 elk. New cases of the disease were diagnosed in deer hunt areas 132 (west of Flaming Gorge) and 157 (east of Pavillion) as well as elk hunt area 10 (west of Laramie).

These hunt areas all are bordered by known positive areas or states and are most likely natural extensions of the endemic area, according to a Game & Fish 2013 CWD report.

The state’s only CWD-positive elk are in southeastern Wyoming, but CWD-positive deer do occupy the Big Horn Basin, according to a Game & Fish 2012 map.

No elk harvested in western Wyoming tested positive last year. If those elk had not been killed by hunters, they would have wintered in the feedgrounds, Langston said.

A total of 3,273 deer, elk and moose samples were analyzed in 2011. Of those samples, 109 tested positive for CWD, representing 81 mule deer, 16 white-tailed deer and 12 elk. One new case of the disease was diagnosed in deer hunt area 165 (north of Meeteetse). Area 165 is bordered by known positive areas and likely a natural extension of the endemic area, said a 2012 Game & Fish report.

“Rocky Mountain elk do very well without feedgrounds, for the most part,” Dorsey said.

For example, in the Gros Ventre area there are three feedgrounds, but there also is good winter range. Conflicts could be mitigated.

“We’d be happy to help find resources to build elk-proof fences to help keep elk separate from cattle and horses during winter and spring, and prevent inter-species transmission of brucellosis,” Dorsey said.

About 80 percent of the elk in seven herd units comprising west-central Wyoming use the feedgrounds. Although nobody knows how many, there would be fewer elk without feedgrounds, said Brandon Scurlock, a Game & Fish brucellosis program supervisor in Pinedale.

Typically, the units are at or over population objectives, Dorsey said.

As examples, the Jackson herd objective is 11,000 elk. The 2012 estimate was 11,051. The Fall Creek herd objective is 4,400. The 2012 estimate was 4,500.

There are 23 feedgrounds in western Wyoming. Of those, 22 are managed by the state and one, the National Elk Refuge in Jackson, is run by the U.S. Fish & Wildlife Service.

Now is the time to phase out the feedgrounds before a CWD epidemic occurs in those areas, Dorsey said.