JACKSON, Wyo. (AP) -- Eleven of 43 elk kept in pens contaminated with chronic wasting disease have died from the disease over the last four years, a 25 percent mortality rate, according to research by the state Game and Fish Department that is being used to help formulate a state management plan for dealing with the disease.

Game and Fish captured female elk calves on the National Elk Refuge in February 2002 and sent them to the state's Sybille Wildlife Research and Conservation Education Center near Laramie. The elk have been housed in pens assumed to be contaminated with the infectious prion that transmits the fatal brain-wasting disease.

The remaining 32 elk will be held throughout their lifetime to document causes of death.

The research results have been added to the state's draft plan for dealing with chronic wasting disease.

The Wyoming Game and Fish Commission is expected to adopt the plan when it meets Friday in Cheyenne.

Results from the Game and Fish research will be used to predict how the disease could affect free-ranging elk populations.

Chronic wasting disease attacks the central nervous system of deer and elk, causing the infected animals to waste away. It's fatal to the animals that contract it and there's no known cure.

The prevalence of the disease in free-ranging elk in Wyoming has ranged from 2 percent to 3 percent. But experts warn that the disease could occur at much higher rates among elk on feed grounds in Sublette, Lincoln and Teton counties because feeding concentrates animals in artificially high numbers.

Originally, the state's draft plan warned that "scientific research has indicated that the prevalence of CWD in captive elk can exceed 50 percent." The 50 percent figure has been removed from the revised plan now going to the commission.

The revised plan also removes language from the original draft that the "possibility of much higher prevalence rates in feed ground elk" could result in a reduction in elk numbers.

The new version of the plan instead says that it is "unknown" what effect disease rates exceeding 2 to 3 percent would have on free-ranging elk numbers. The plan states that data from the captive elk at Sybille will be used to generate predictions of population effects, but does not give any predictions.

Franz Camenzind, executive director of the Jackson Hole Conservation Alliance, said the revised draft plan is disappointing because it doesn't appear to take the risk of chronic wasting disease killing large numbers of elk on feed grounds seriously.

So far, the disease has not been detected on elk feed grounds.

Conservationists support phasing out feed grounds before chronic wasting turns up on them, and several environmental groups sued the federal government last week seeking an environmental review of elk feeding. But many hunters and ranchers want the elk feed grounds to remain because they help elk survive the winter and keep the animals away from hay stacks used to feed livestock.

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