The Oklahoma Department of Wildlife Conservation (ODWC) has confirmed the state’s first case of chronic wasting disease (CWD) in a wild deer—making it the 31st U.S. state to report the always-fatal neurological disease in free-ranging cervids. A landowner recently reported the diseased deer to the ODWC “after witnessing it behaving abnormally,” the state agency said in a June 6 press release. It’s the first positive case of CWD in over 10,000 lab-tested tissue samples from the state’s wild deer and elk, stretching back more than 20 years.

“While this is unfortunate news, it is not unexpected since CWD has already been detected in every state that borders Oklahoma,” said Jerry Shaw, Wildlife Programs Supervisor with ODWC, in the press release. “We will be working through our response plan to ensure we can monitor potential spread and keep our state’s deer herd healthy.”

The CWD-infected whitetail was found in Texas County, Oklahoma, which is situated in the state’s western panhandle and borders both Kansas and Texas. Kansas detected the disease for the first time in 2020 in a farmed bull elk. Texas has harbored it since at least 2012, when it was discovered in a free-ranging mule deer in the Hueco Mountains in the far western part of the state.

CWD was found in captive animals for the first time in Oklahoma 1998. That case emerged in Oklahoma County within a farmed elk herd imported from Montana. The disease wasn’t detected again in the Sooner State until April 2019, when a single farmed elk in a herd east of Oklahoma City tested positive. In 2022, Texas Parks & Wildlife Department (TPWD) found a road-killed deer with CWD just 2.5 miles from the Oklahoma-Texas border near the town of Felt, Oklahoma. That’s when the ODWC began implementing its CWD response plan.

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In response to this recent case of CWD in a wild whitetail in Texas County, the ODWC has now activated the second phase of that CWD response plan in coordination with the Oklahoma Department of Agriculture, Food and Forestry. “The Wildlife Department will continue monitoring for evidence of this disease within Oklahoma’s borders and will release additional information,” the ODWC said in the release, “including ways deer and elk hunters can help with detection and mitigation, as hunting seasons approach.”