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.