Chronic wasting disease expands range in Texas, Montana

White-tail buck in snow
White-tail buck in snow

mrpolyonymous / Flickr cc

Officials in both Texas and Montana have reported new cases of chronic wasting disease (CWD) in previously unaffected parts of their states, while Mississippi is noting a CWD increase in its deer population.

CWD-positive deer in south Texas

In Texas, CWD was confirmed in a free-ranging 5-year-old white-tailed doe between Del Rio and Amistad Reservoir, signaling the first detection of the disease in Val Verde County, which is in south central Texas along the Rio Grande.

CWD has not been detected in any neighboring county, according to Texas Parks and Wildlife Department (TPWD) data.

The TPWD and Texas Animal Health Commission are implementing a containment strategy to limit disease spread after the Val Verde County detection, according to a TPWD news release yesterday. The neurologic disease, caused by a misfolded protein called a prion, is always fatal in cervids like deer and elk but has not yet spread to people, though officials fear it one day may do that.

"Because eradication is thought to be impossible once CWD becomes established in a population, it is imperative that we work with other agencies, landowners, and hunters to contain this disease," said Bob Dittmar, DVM, the TPWD's wildlife veterinarian. "This containment strategy is particularly urgent considering this detection happened in the middle of the general deer season."

Texas officials first detected CWD in a mule deer in 2012 in the western part of the state.

First case in southwestern Montana

In Montana, meanwhile, Montana Fish, Wildlife & Parks (MFWP) said that a white-tailed buck harvested by a hunter in the Ruby Valley represents the first CWD detection in the southwestern part of the state, according to a press release.

Samples from the deer are among 24 across the state that tested positive for CWD, which can only be done currently on dead animals. The other positive samples were within CWD management zones where the disease is known to already exist.

The Ruby Valley deer was harvested on private land about a mile west of Sheridan in Madison County.

Montana scientists have assayed samples from 7,000 cervids so far this year, and 115 (1.6%) tested positive for CWD. Last year state officials confirmed only 26 CWD cases in wild deer. The general deer hunting season is now closed in the state.

The disease was first detected in Montana in the wild near Billings in 2017.

Twelve suspected cases in Mississippi

Mississippi officials are reporting 12 suspected new CWD cases, 2 of which have been confirmed, the Jackson Clarion Ledger reported this week.

"We have 12 (new) cases," said Russ Walsh, Mississippi Department of Wildlife, Fisheries, and Parks Wildlife Bureau chief of staff. "Ten are in the process of being confirmed."

All have been found since October, with 11 in Benton County and 1 in Marshall County. Both of these adjoining counties in northernmost Mississippi have had previous cases.

Prior to this year, Mississippi has confirmed 19 total CWD cases. Walsh said the increase is expected, given that neighboring Tennessee recently reported 148 since the beginning of hunting season, with the lion's share of cases near the Mississippi border.

"It leads you to believe [the new Mississippi cases] are a part of the Tennessee outbreak," Walsh said. "That's what we believe given their proximity to the state line and their confirmed cases."

See also:

Dec 19 TPWD news release

Dec 18 MFWP press release

Dec 17 Clarion Ledger story

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