No CWD detected in Minnesota’s wild deer; bovine TB results pending

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No CWD detected in Minnesota’s wild deer; bovine TB results pending
(Released June 17, 2010)


All of the samples from wild deer taken last fall by hunters in southeastern Minnesota that were tested for the presence of Chronic Wasting Disease (CWD) have come back negative for the disease.


“This is good news for Minnesota,” said Dr. Erika Butler, wildlife veterinarian for the Minnesota Department of Natural Resources (DNR). “Extensive tests on wild deer in southeastern Minnesota and additional targeted tests of sick animals statewide all have been CWD negative.”

DNR conducted tests on 2,685 deer that hunters harvested last fall in southeastern Minnesota. An additional 28 deer from other parts of the state were sampled because they displayed clinical signs of an illness. None tested positive for CWD.

CWD naturally occurs in cervids, which include North American deer, Rocky Mountain Elk and moose. The disease belongs to a group of infectious diseases known as “transmissible spongiform encephalopathies” (TSEs). It is caused by an abnormal protein called a prion, which affects the animal’s brain and is invariably fatal. Usually, months to years pass from the time an animal is infected to when it shows signs of the disease.

CWD infected captive elk were discovered on a farm near Pine Island in 2009. As a result, the Board of Animal Health (BAH) and U.S. Department of Agriculture (USDA) depopulated the farm’s elk and DNR conducted extensive testing for CWD in southeastern Minnesota wild deer during last fall’s firearms deer hunting season.

A high proportion of the samples were obtained within a 15-mile radius of the CWD-positive captive elk farm, as well as along the Minnesota-Wisconsin border where Minnesota deer are in closest proximity to an area of Wisconsin where CWD infection is established in wild deer.

“DNR has collected more than 33,000 samples in statewide surveillance efforts since CWD testing began in 2002 and all tests have been negative,” Butler said. “However, periodic surveillance in the vicinity of previous cases of CWD in captive cervids and along the Wisconsin border remains prudent.”

Surveillance efforts within a 15-mile radius of the CWD-infected cervid farm in Olmsted County will be repeated during 2010 firearm hunting season. Targeted surveillance of suspect deer will continue throughout the state.

Typical signs of CWD include drooping head or ears, poor body condition, tremors, stumbling, increased salivation, difficulty swallowing, or excessive thirst or urination. The disease was first discovered in Colorado and Wyoming, and has since been detected in wild or captive animals in Illinois, South Dakota, North Dakota, Nebraska, Kansas, Michigan, Nebraska, New York, Virginia, West Virginia, Oklahoma, New Mexico, Montana, Utah, Wisconsin, Saskatchewan and Alberta.

The World Health Organization and the U. S. Center for Disease Control and Prevention have found no scientific evidence to date that CWD can be transmitted to humans.

Bovine tuberculosis (TB) results pending

One of 1,488 deer harvested by hunters during the fall of 2009 in northwestern Minnesota tested positive for bovine TB.  From February to April of 2010, an additional 450 deer were removed by ground sharpshooting from a smaller area around where all previously bovine TB positive deer have been found.  None showed clinical signs of the disease. Final lab results are pending.

As of June 10, 2010, bovine TB had been confirmed in 27 of 8,144 free-ranging deer tested over the course of six years. To date, all infected deer have been animals born during or before 2006 and taken within 10 miles of Skime, where a cluster of four bovine TB-infected cattle farms were found.

Aggressive population management utilizing liberalized hunting seasons will continue during 2010 in Deer Permit Area 101 as DNR continues to work with BAH and Agriculture Department officials to eradicate bovine TB in Minnesota. The DNR will continue to conduct fall disease surveillance annually until five consecutive years with no bovine TB-positive wild deer identified