The crawl of chronic wasting disease in South Dakota deer continues to move eastward.

Officials from the South Dakota Department of Game, Fish and Parks said last week that CWD was recently confirmed in Lyman and Sully counties.

CWD has now been confirmed in 14 of the state’s 66 counties and in the case of Sully County, has been confirmed for the first time East River.

“We’ve learned that CWD is not a disease just restricted to the Black Hills and West River counties and this definitely creates some challenges moving forward,” said GF&P wildlife program administrator Chad Switzer in a statement. “We have expanded our surveillance efforts for the 2020 hunting seasons, and hunters submitting their harvested deer from priority surveillance areas is key to determining CWD presence in South Dakota."

The confirmations mean that the counties have been added to the state’s endemic area list: which includes Bennett, Butte, Corson, Custer, Fall River, Haakon, Harding, Jackson, Meade, Lawrence, Pennington and Tripp. Any deer or elk hunting unit that includes any portion of these counties is considered a CWD endemic area. Eight of the 14 counties were added in fall 2019.

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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.

Earlier this year, South Dakota approved new regulations that require a hunter, taxidermist or game processor to dispose of carcass parts from a harvested deer or elk to an area not known to have CWD with a waste management provider or landfill that accepts carcass parts. (For hunters not moving a deer or elk carcass outside of a CWD endemic area, the transportation regulation does not apply. Deer or elk carcasses from another state brought back into South Dakota must be disposed of with a waste management provider or landfill that accepts carcass parts.) Research has shown that CWD infected carcasses may be a primary method for the spread of the disease.

South Dakota had more than a dozen CWD collection sites at businesses near the endemic areas in the central region of the state, and also at nine GF&P regional offices statewide.

CWD poses serious problems for wildlife managers, and the implications of long-term management for free-ranging deer and elk is unknown.

Surveillance statistics from GF&P indicates that sick deer and elk with CWD remains relatively rare in free-roaming animals, especially when considering how many animals are out there. The state reported 95 positive deer and elk — 15 mule deer, 59 white-tailed deer and 21 elk — in the testing period of July 1, 2019 to June 30, 2020. As of the end of June, South Dakota has found 546 cases of CWD (311 deer and 235 elk) since the state began testing animals in 1997, with about one-third of those cases in Wind Cave National Park. Nearly 30,000 wild deer and elk have been tested for the disease since 1997.

The GF&P said the most recent positive samples were obtained from two male white-tailed deer by hunters in Lyman County and one male mule deer from sick surveillance in Sully County.