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2020 CWD testing shows a low prevalence of disease in areas tested

Testing results from Minnesota’s 2020 hunting season and early 2021 special hunts confirmed chronic wasting disease in 22 wild deer, all within current disease management zones, according to the Minnesota Department of Natural Resources.

In total, 7,682 samples were tested from hunter-harvested deer or opportunistic samples (deer killed by vehicles, reported sick or found dead). Nineteen of the positives were from deer in the southeast management zone and three were from the south metro management zone.

CWD was not detected in the north-central disease management zone, the southeast control zone, or the surveillance areas put in place for the 2020 hunting season. The surveillance areas added in 2020 were in east-central and west-central Minnesota, as well as a south metro surveillance area that surrounds the south metro management zone.

“Though CWD is detected in Minnesota’s wild deer, our recent test results show that the disease prevalence remains relatively low,” said Erik Hildebrand, DNR wildlife health specialist. “Keeping deer healthy is our priority, and we continue to take aggressive action in areas where the disease has been detected in wild deer and monitor for the disease in areas where there are elevated risks for CWD.”

Some test results from the year’s management activities and any deer reported sick or dead are still pending; results will be updated on the DNR’s CWD webpage as they become available.

The DNR monitors CWD by testing wild deer. When the disease is detected in either captive or wild deer, the DNR establishes surveillance areas and tests wild deer for at least three years after the detection. This is because it can take 1 ½ to 3 years before a deer shows clinical symptoms. If three consecutive years of test results fail to confirm CWD, and an adequate number of deer are sampled, the DNR will end surveillance in an area.

In fall 2020, the DNR shifted to voluntary self-service sampling to facilitate social-distancing measures at sampling stations during the COVID-19 pandemic. With the shift, the DNR set sampling goals that would allow the agency to confidently assess disease prevalence in an area. While the majority of areas received enough samples to meet sampling goals, some surveillance areas did not.

The DNR will continue sampling for disease in these areas to enhance confidence about disease detection.

“We appreciate all those who participated in sampling this year,” Hildebrand said. “Each deer tested gives valuable information that contributes to our understanding of the disease’s prevalence and geographic distribution in our herd.”

Where CWD has been detected in wild deer, the DNR uses a three-pronged approach to limit the spread of the disease and keep Minnesota’s wild deer population healthy: reducing deer densities, restricting deer feeding and attractants, and limiting deer carcass movement.

This year, in areas where CWD-positive deer were detected, the DNR held two special hunts after the firearms hunting season and also provided landowners within a 3-mile radius of positive deer with shooting permits to further reduce deer densities.

From February through March, the DNR will work with the U.S. Department of Agriculture-Wildlife Services to complete targeted culling in focused areas where CWD has been detected in wild deer. Venison from these deer that do not test positive for CWD will be donated through the Share the Harvest program.

Final CWD test results will influence how the DNR manages the disease going forward and determines the 2021 hunting regulations, which will be released in August.

Keeping Minnesota’s wild deer population healthy remains the goal of the DNR’s response to CWD. Since CWD was first detected in Minnesota in 2002, the DNR has tested more than 90,000 wild deer in the state. To date, 110 wild deer have tested positive for CWD in Minnesota. CWD test results, including locations of confirmed positive test results and statistics, are available on the DNR website at mndnr.gov/cwdcheck.

As part of its CWD response plan, the DNR monitors and manages for CWD in disease management zones around areas where the disease has been detected in wild deer. The CWD management zones are located in the southeast, north-central and south metro areas of Minnesota. The DNR monitors for the disease in surveillance areas where CWD has been found in captive deer farms or which are adjacent to other areas of known risk located in the east-central, west-central and south metro areas of Minnesota.

CWD is always fatal and affects the deer family, which includes deer, elk and moose. There is no vaccine or treatment for this disease.

For more information on chronic wasting disease, including maps of CWD surveillance areas, frequently asked questions and hunter information, visit mndnr.gov/cwd.