Throw disease to the wolves?

Park eyes predators to control chronic wasting in elk

By Theo Stein
Denver Post Staff Writer

Predation by wolves may be an effective way to stop a deadly brain disease of deer and elk in Colorado, according to a recent study.

A modeling study based on conditions at Rocky Mountain National Park shows wolves could have “potent effects” on the rate of chronic wasting disease in the park’s overabundant elk herds, according to three Colorado researchers.

Existing control efforts, which focus on intensive culling to reduce herd numbers, have been expensive and, so far, ineffective.

“We need to think outside the box,” said National Park Service wildlife veterinarian Margaret Wild. “We’ve got to come up with some different tools.”

Chronic wasting disease is a transmissible spongiform encephalopathy like mad cow disease. Unlike mad cow, it is contagious and persists in the environment for years.

There is no evidence that CWD has ever sickened a human, but health experts warn hunters not to eat the meat of an infected animal.

Since it was identified in Colorado in 1977, CWD has hopscotched to Wyoming, Utah, Nebraska, Illinois, Wisconsin, New York and Saskatchewan.

Studies have shown that wolves prey on the weak or sick. That behavior could help remove contagious animals from the population and reduce infection rates, according to Wild. Wolves also could help scatter herds of deer and elk, further reducing the risk of transmission, she said.

Field research will be needed to show what effect, if any, wolves have on CWD, she said.

Some prominent wolf biologists have offered cautious support.

“I need to see the data,” said L. David Mech, a University of Minnesota professor. “If the claim is valid, there may be some value in terms of

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controlling CWD. But it needs some pretty good documentation before it will be accepted.”

Rocky Mountain National Park is evaluating whether wolves could help cull and redistribute elk herds that have overbrowsed aspen and willow.

The only promising CWD control technique is now in a third year of study in Estes Park. The Colorado Division of Wildlife has biopsied the tonsils of tranquilized mule deer, fitted the animals with radio collars and removed those found to be infected.

CWD rates do appear to be declining in the project area, division veterinarian Mike Miller said. But at about $660 an animal, the cost makes the technique unsuitable for backcountry applications.

The research does not involve elk because no live test for elk has been developed.

The strategy of testing and culling is essentially what wolves do, Miller said.

“They’d be paid by the pound, not by the hour,” he said. “Wolves would always be on the clock.”

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