Chronic wasting disease discovered in Allegany County

State says it has plan in place to deal with illness that can spread quickly through deer populations

February 10, 2011|By Candus Thomson, The Baltimore Sun

Despite Maryland's best efforts to stem a national tide, a fatal illness akin to mad cow disease has been detected in a single white-tailed deer in Allegany County.

The confirmation — making Maryland the 20th state to be touched by chronic wasting disease — came Thursday from laboratory tests of deer brain stems from the hunting season that just ended.

"From our perspective this was inevitable, but it's far from doomsday," said Paul Peditto, director of the Department of Natural Resources Wildlife and Heritage Service. "The good news is that our preparation and planning ensure a sound scientific foundation for our response to this single positive test result."

Chronic wasting disease, first identified in Colorado in 1967, attacks the brains and nervous systems of captive and wild deer, moose and elk. It has spread east and north and has resulted in the killing of thousands of captive elk in Colorado and hundreds of deer in Wisconsin.

A transmissible spongiform encephalopathy, CWD is in the same family as "mad cow" disease, scrapie, which affects sheep, and Creutzfeldt-Jakob Disease, which attacks humans. Infected animals stagger, slobber and show little fear of humans. They gradually lose the ability to keep themselves alive.

It is easily transmissible within deer and elk populations, according to the Centers for Disease Control and Prevention, but the exact method has not been pinpointed. However, there are no known cases of CWD infecting people or livestock.

The Maryland deer was shot on Nov. 27, the opening day of firearms season at Green Ridge State Forest. That deer, along with 359 others, were tested as part of a state program that dates back to 1999.

The low deer density in the state forest will help prevent any rapid spread of the disease, Peditto said.

Six years ago, Maryland developed a response plan that concentrates testing within a five-mile circle of where the infected animal was found.

Peditto said Maryland has benefitted from lessons learned in other states. So instead of deploying sharpshooters to kill 300 deer, the new model allows biologists to gather samples this year from road kills and deer shot as part of the crop damage abatement program. Those tests will be augmented by hunter-killed deer in the fall. Additional positive tests would expand the boundaries.

"Instead of running around trying to find deer, we'll let the deer come to us," he said.

Despite years of study, CWD still confounds scientists. At first, wildlife managers felt the Mississippi River would act as a natural firewall, but the disease jumped the river and infected animals in Wisconsin and Illinois. Then it hop scotched over several states, showing up in 2005 in white-tailed deer in West Virginia and New York. Last year, Virginia joined the list.

So far, infected deer in this region have been concentrated in a small area around Maryland's panhandle. Virginia has had just a single infected deer, but West Virginia last month announced tests had detected 10 new cases, bringing the state's total to 84.

Research indicates captive animals are more likely to become infected and spread the disease. In the mid-1980s, Maryland approved regulations that effectively banned deer and elk ranching and in 2002 officials banned anyone from owning or transporting deer.

But state officials long feared that the disease could spread from captive herds of deer and elk in Pennsylvania, which has about 800 licensed facilities and an equal number of unlicensed ones.

Jerry Feaser, spokesman for the Pennsylvania Game Commission, said all of the elk killed last season tested negative and the state is still awaiting results from the tests on 4,000 deer.

Some states with CWD have seen a temporary decline in hunting. In Wisconsin, where wildlife officials eradicated 25,000 deer from a 411-square-mile tract, hunters grew fearful of handling infected deer. Hunting license sales fell 10 percent in 2003 and the number of deer killed dropped by nearly 30,000, despite a $300,000 campaign by a hunting group.

But Peditto doesn't see that happening here.

"We know so much more than we did in 2003. CWD will occasionally show up on the landscape and it will be part of our management plan," he said. "It will have little or no impact on the deer population or hunters."

candy.thomson@baltsun.com

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