PIERRE — The South Dakota Department of Game, Fish and Parks said Monday that chronic wasting disease, or CWD, has now been confirmed in 12 counties in the state.

The disease was recently confirmed in the counties of Butte, Corson and Haakon in western South Dakota, according to samples provided by hunters. One male white-tail deer from both Butte and Corson counties tested positive, while two male mule deer tested positive from Haakon County.

Twelve counties in South Dakota are now known to be infected with CWD, which includes eight counties added during the fall of 2019. The state's endemic counties are all West River and include: Bennett, Butte, Corson, Custer, Fall River, Haakon, Harding, Jackson, Meade, Lawrence, Pennington and Tripp.

“We’ve learned that CWD is not a disease just restricted to the Black Hills and surrounding area and this definitely creates some challenges moving forward,” said GF&P Wildlife Program Administrator Chad Switzer in a statement. “As the surveillance efforts from the 2019 hunting seasons come to end, an update will be provided to the GFP Commission in March and a report will be made available to the public on our website."

Chronic wasting disease (CWD) is a fatal brain disease of deer, elk, and moose caused by an abnormal protein called a prion. Animals in the later stages of infection with CWD may show progressive loss of weight and body condition, behavioral changes, excessive salivation, loss of muscle control and eventual death. Chronic wasting disease is always fatal for the afflicted animal. CWD poses serious problems for wildlife managers, and the implications of long-term management for free-ranging deer and elk is unknown.