Lab analysis reported on chronic wasting disease

OBERLIN -- Tissue samples from deer collected earlier this month in Decatur County all have tested negative for chronic wasting disease (CWD), reports the Kansas Department of Wildlife & Parks.

After three deer taken by hunters in that area during the 2007 hunting season tested positive for the disease, KDWP biologists collected an additional 39 deer in Decatur County Feb. 11 through 13. Screening tests performed by Kansas State Veterinary Diagnostic Laboratory on those 39 samples yielded results that KDWP and Decatur County hunters and landowners wanted to hear: no additional positive results for the disease.

The additional samples were collected to gauge the prevalence of the disease in other deer in the area, said Dr. Ruby Mosher, KDWP’s wildlife disease coordinator. The meat from those deer was given to Decatur County residents.

“We truly appreciate the help and cooperation of the citizens and landowners of Decatur County,” Dr. Mosher said. “We couldn’t have done what we did (additional sampling) without the help of Decatur County officials and staff. We also appreciate the cooperation of the Kansas Department of Transportation for allowing us to use their facility in Oberlin for initial processing of the deer.”

Dr. Mosher said that lab analysis of about 1,650 deer tissue samples submitted by Kansas hunters during the past hunting season have yielded no additional positive CWD results. KDWP is awaiting results of another 550 hunter-submitted samples from the 2007 deer season, but all of those are from the eastern half of the state, where the known risk of CWD is lower than western Kansas. Analysis of all hunter-submitted samples from the western half of the state is complete.

CWD had been detected twice in Kansas prior to the latest occurrence in Decatur County. The first case was in 2001 in a captive elk herd in Harper County. The other occurred during the 2005 hunting season in a wild whitetail doe harvested in Cheyenne County.

Earlier this year, the Nebraska Game and Parks Commission reported a CWD-positive deer from an area just a few miles north of Decatur County, in Red Willow County, Nebraska.

KDWP biologists have conducted annual sampling of hunter-harvested and road-killed deer since 1996.

Although research is underway, there is currently no vaccine or other biological method of preventing CWD. The only tool is to prevent the spread of CWD to new areas, because once the infective particle (an abnormal prion) is deposited into the environment -- either through an infected carcass or from a live animal -- it may exist for a decade or more, capable of infecting a healthy deer.

Despite the recent occurrences, the likelihood of finding CWD in a wild deer harvested in Kansas is small. That small likelihood decreases even more the farther from northwestern Kansas the deer lived. In recent years, numerous cases of CWD have been documented in neighboring areas of Colorado, Nebraska and Wyoming.

While CWD is fatal to infected deer and elk, humans have never been known to contract the disease. CWD is a member of the group of diseases called transmissible spongiform encephalopathies (TSEs). Other diseases in this group include scrapie in sheep and goats, bovine spongiform encephalopathy (BSE or mad cow disease) in cattle, and Cruetzfeldt-Jacob disease in people.

CWD is a progressive, fatal disease that results in small holes developing in the brain, giving it a sponge-like appearance under the microscope. Decreased brain function causes the animal to display neurological symptoms such as depression, droopy head, staggering, loss of appetite, and a lack of response to man. The continuing deterioration of the brain leads to other symptoms such as weight loss, drooling, and excessive thirst. Caution is advised because of unknown factors associated with prion diseases, but no human health risks have been discovered where CWD occurs.

The symptoms of CWD include loss of body weight, stumbling, holding the head at an odd angle, circling, non-responsiveness to people, and pneumonia. Any sick deer or elk should be reported it to the nearest KDWP office or the Emporia Research Office, 620-342-0658.

Hunters can help protect the health of the Kansas deer herd by taking the following steps to avoid accidentally introducing CWD to a new area in Kansas:

• do not transport deer carcasses far from the area where the deer lived, especially from areas where CWD has been detected, such as northwestern Kansas; and
• if a carcass is transported, the hunter should make sure that carcass waste is not dumped into the environment where local deer or elk can come into contact with it. Carcass waste can be disposed of by double-bagging it and taking it to a landfill.

The Chronic Wasting Disease Alliance maintains an online clearinghouse of information about the disease. More information is also available on the KDWP website.

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