In Fight Against Chronic Wasting Disease, New Rules for West Texas Deer Hunters
It was first identified in captive mule deer in Colorado. It's now spread to 23 states and two Canadian provinces. In 2012, it was detected in Texas mule deer.
Chronic Wasting Disease, or CWD, is a fatal neurological disorder that affects deer, elk and related species. While its origins are mysterious, it's among a class of disorders known as spongiform encephalopathies, which also includes BSE, or “mad cow disease.”
In our region, the disease is confined to deer in the Hueco Mountains, east of El Paso. It's not known to be transmissible to humans. But there's a statewide effort to monitor CWD – and to limit its spread.
In 1967, managers at a Colorado wildlife research facility began to lose mule deer. The deer became listless. They lowered their heads and walked in repetitive patterns. They developed tremors. Within weeks of exhibiting symptoms, the deer died.
Scientists recognized a “wasting” syndrome. But it took years to identify the cause. In 1980, the disease was determined to be a “transmissible spongiform encephalopathy.” By 1981, CWD had been confirmed in wild deer and elk in Colorado and Wyoming.
Shawn Gray is mule deer program leader for Texas Parks and Wildlife. He said the agent of transmission for CWD is unusual.
“It's a fatal neurological disease – it's not a bacteria, it's not a virus,” Gray said. “It's caused by a mis-folded protein called a prion – so get your head around that one.”
A prion is an abnormal form of a common protein. The prion causes normal proteins to convert to the abnormal form. It strikes the central nervous system, causing progressive, and invariably fatal, brain degeneration.
“They're emaciated – that's where the word 'wasting' comes from,” Gray said of infected deer. “They have a really rough coat. They salivate. They have a droopy head. They walk in circles. They can run around the wild for months or years and have the disease and not show clinical signs. When they start showing clinical signs, that's when they're fixing to die.”
Prions are transmitted through the saliva, urine, feces and antler velvet of infected deer. But they can also linger for years in grass upon which infected animals have fed – or in soil where a casualty has decomposed.
CWD was confirmed in New Mexico in 2005. In March 2012, New Mexico officials notified Texas of infected deer in the Hueco Mountains, near the state line.
Texas activated a CWD Task Force. Wildlife managers harvested 31 deer in Hudspeth and El Paso counties. Two CWD positives were found, in Texas' Hueco Mountains.
Since then, Texas has imposed new regulations. The 2016 Trans-Pecos mule deer season is Nov. 25 to Dec. 11. Hunters are urged to know the rules.
Parks and wildlife has defined “containment” and “surveillance” zones. The zones include all of El Paso and Hudspeth counties, and much of Culberson County. It's illegal for an intact deer carcass to leave either of the zones.
Hunters who harvest a deer within the zones must bring the carcass – or intact head – to a check station. Stations are located in Van Horn, at Cornudas and on Hwy. 62/180 near the New Mexico line.
The stations are open 9 a.m. to 9 p.m. during the hunting season, and 9 a.m. to 6 p.m. Dec. 12.
Hunters can later find CWD test results online. Hunters who plan to take the head to a taxidermist receive a special form.
Since 2012, thousands of samples have been tested. Locally, the disease hasn't been found outside the Huecos. But the disease was confirmed in captive deer in Central Texas in 2015. And it was detected in the Panhandle in 2016.
Federal health officials say the risks to humans are low. CWD is not known to be transmissible to people or other animals outside the deer family.
In some herds in Colorado, as much as 50 percent of mule deer are infected. CWD can impact West Texas wildlife ecology. But mule deer hunting is also big business. And the disease could spread east – threatening the larger enterprise of white-tailed deer hunting.
Gray said that, so far, regulations have not hurt hunting in the Trans-Pecos.
“We don't want that to happen, and we're hoping that the rules don't do that,” Gray said. “We're just hoping to find as much data to back up our management decisions. We're just trying to err on the side of caution.”
For more information, and for details on hunting regulations, visit Texas Parks and Wildlife's CWD webpage:http://tpwd.texas.gov/huntwild/wild/diseases/cwd/