Texas has become the 18th state to confirm Chronic Wasting Disease (CWD) in its mule deer population after two animals tested positive for the disease in early July.
The animals were collected during regular sampling tests in the Hueco Mountains in Hudspeth County after mule deer in New Mexico were reported positive in mid-June. Following that incident, Texas Parks & Wildlife (TPWD) biologists and Texas Animal Health Commission (TAHC) officials established an immediate containment zone in an effort to prevent the movement of the disease outside the area of detection.
“Texas Parks & Wildlife was notified by animal health officials in New Mexico back in February that mule deer near the Texas border had tested positive for CWD and we immediately called together our special task force to freshen our plans for response,” reported Clayton Wolf, Wildlife Division Director for TPWD in the Trans Pecos region. “We have known and planned for a long time the possibility CWD would reach our state borders so we had a very clear direction on what to do in response.”
Wolf, TWPD Trans Pecos Mule Deer Coordinator Shawn Gray and TAHC Assistant Executive Director Dr. Andy Schwartz fielded reporter questions during a special teleconference Tuesday afternoon.
With the assistance of cooperating landowners, TPWD, TAHC, and USDA-APHIS-Wildlife Services biologists and veterinarians collected samples from 31 mule deer as part of a strategic CWD surveillance plan designed to determine the geographic extent of New Mexico's findings. Both infected deer were taken from the Hueco Mountains of northern El Paso and Hudspeth counties.
CWD is a member of the group of diseases called transmissible spongiform encephalopathies (TSEs). Other diseases in this group include scrapie in sheep, bovine spongiform encephalopathy (BSE or mad cow disease) in cattle, and Cruetzfeldt-Jakob disease in humans. CWD among cervids is a progressive, fatal disease that commonly results in altered behavior as a result of microscopic changes made to the brain of affected animals.
An animal may carry the disease for years without outward indication, but in the latter stages, signs may include listlessness, lowering of the head, weight loss, repetitive walking in set patterns, and a lack of responsiveness. CWD is not known to affect humans.
Tissue samples were initially tested by the Texas Veterinary Medical Diagnostic Laboratory in College Station, with confirmation by the National Veterinary Services Laboratory in Ames, Iowa.
“This is not a crisis, but it is a significant development. We have had an active CWD surveillance program in place for more than a decade and have tested a large number of deer since 2002. Under terms of the containment zone, we will continue to monitor deer movement, work with property owners in identifying and testing suspect animals and will establish wildlife checkpoints throughout hunting season in an effort to monitor CWD within the area,” said Dr. Andy Schwartz.
The mandatory hunter checkpoints will evaluate deer prior to movement outside the containment zone and may require testing of suspect animals. Voluntary checkpoints will be established in a secondary or high risk zone. Wolf says TPWD also will work with local and state law enforcement officials to collect and test road kill animals.
“In the last stages of the disease, animals are known to become disorientated and often will end up running into traffic, so between road kill testing and hunter inspections, we hope to get a better idea on the movement of the disease and how well it has adapted to animals within the zone,” he added.
In addition to mule deer, Schwartz says white-tail deer, sika, red deer, elk and moose are at risk from the disease. The TAHC regulates cervid species not indigenous to Texas such as elk, red deer, and sika deer, and oversees a voluntary CWD herd monitoring status program with the intent to facilitate trade and marketability for interested cervid producers in Texas.
Cervid herds under either TPWD or TAHC authority may participate in the commission's monitored CWD program. The basis of the program is that enrolled cervid producers must provide an annual herd inventory, and ensure that all mortalities during the previous year were tested for CWD and the disease was not detected.
The disease was first recognized in 1967 in captive mule deer in Colorado. CWD has also been documented in captive and/or free-ranging deer in 19 states and 2 Canadian provinces, including neighboring New Mexico.
"We know that elk in southern New Mexico are also infected with CWD," said Dr. Schwartz. "It will take a cooperative effort between hunters, the cervid industry, and state/federal animal health and wildlife agencies to ensure we keep this disease confined to southern New Mexico and far West Texas.”
Schwartz says he is confident the plans of the CWD task force will be able to protect the cervid industry in Texas.