A fatal brain disease has been confirmed in a deer in Union County, just the third East River county where the disease has been detected, South Dakota Game Fish & Parks announced.

The presence of chronic wasting disease in a Union County deer could mean that the malady is widely present across the state. The Union County confirmation is the 20th county with a confirmed case in free-ranging white-tailed and mule deer. Most of those counties have been on the western side of the state, and prior to Union County, the other two East River counties were Buffalo and Sully in central South Dakota.

The widening presence of highly infectious CWD could pose doubts about the future of the state’s free-ranging deer population. The disease also infects elk and moose.

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