By Jessica Domel
Multimedia Reporter

Texas landowners and deer hunters will need to check the Texas Parks and Wildlife Department’s (TPWD) website this fall as many Chronic Wasting Disease surveillance zones have already or will soon change.

The Texas Parks and Wildlife Commission recently approved proposed changes to how TPWD creates and eliminates CWD surveillance zones after the fatal, neurological deer disease is found in a deer breeding facility.

“CWD detection solely in a captive breeding facility will see significant changes in terms of zone establishment,” Dr. J Hunter Reed, veterinarian for TPWD’s wildlife division, told the commission.

Surveillance zone requirements
CWD surveillance zones come with a set of requirements for deer hunters and breeders.

Within these zones, the movement of live deer is restricted, and hunters are required to bring their harvested deer to a check station to be tested for CWD prior to leaving the zone.

There are also deer carcass movement restrictions to prevent the spread of the disease in CWD-susceptible species like mule deer, white-tailed deer and elk.

The new rules outline procedures TPWD will take when CWD is found in a breeding facility.

“First, we’d establish a quarantine administered by TAHC (the Texas Animal Health Commission) that would be established around the infected property,” Reed said. “Then, a surveillance zone will be established two miles from the perimeter of the infected premise.”

In practice, all properties that are wholly or partially within a surveillance zone will be subject to mandatory CWD testing and carcass movement restrictions.

Lifting surveillance zones
The new rules also outline when a CWD surveillance zone may be lifted.

“This surveillance zone would remain in place until certain conditions are met for the zone to be removed,” Reed said. “The first being the infected breeding facility must be depopulated, or the quarantine administered by TAHC must be lifted.”

A minimum of three hunting seasons must also have passed since the date of depopulation and the quarantine being lifted.

“Area sampling must be completed to satisfy a 95% detection probability goal, and area sampling will be distributed across the zone,” Reed said.

The 95% detection probability and sample distribution metrics are determined by an agent-based model using Texas-specific data.

The new rules will be used to adjust the size of current CWD surveillance zones that were put in place after a positive detection of CWD at a deer breeding facility.

“For Duval County, this would result in a 97% reduction in affected landowners,” Reed said.

The number of affected landowners in Limestone County will be reduced by 76%.

In Gillespie County, that number will be reduced by 91%.

The surveillance zone in Uvalde County may be split into two surveillance zones.

“In this situation, we have two affected breeding facilities relatively close to each other,” Reed said. “One is depopulated, and one is under a research plan. Using this new approach, we would reduce the amount of impacted landowners by 69%.”

In March and April, TPWD confirmed 10 new cases of CWD in five Texas counties. Two additional positives followed in May. One of those detections was in a free-ranging deer.

Reed explained why TPWD was considering smaller surveillance zones around breeding facilities despite these detections.

“I think one point is that our ability to contain the disease in a captive situation, if done in an expeditious manner, is much more effective,” Reed said. “Treating captive facilities in a different context compared to our free-ranging positives is justifiable in that sense because using the tools of depopulation, as well as cleaning and disinfection procedures, as well as having a quarantine in place for at least five years after depopulation, can contain the disease in that context.”

If there is a positive detection in a breeding facility, Reed clarified that the surveillance zone may be lifted after three seasons. However, a quarantine of the facility will remain in place five years from the last detection, according to their herd plan.

The surveillance zones around the facilities are used to detect if the disease is in the native deer population in the area.

“We want to make sure that we’re assessing the free-ranging population surrounding the facility. There could be a free-ranging CWD that we have yet to detect that infected the facility,” Reed said. “We also want to make sure that surveillance zone is in place long enough so that we can also assess if CWD is in the free-ranging population at a high prevalence and that our containment strategy worked in containing it to just that property.”

New surveillance zones
The commission also recently approved five new CWD surveillance zones.

“The first surveillance zone is in Zavala County. The breeding facility in Zavala County was detected after deer were antemortem rectal tested for release, and this resulted in three positives,” Reed said. “It should also be noted that the additional animal has been found to be CWD-positive through postmortem testing. This animal was actually antemortem tested and previously tested not detected around three months prior before testing ultimately CWD positive through post-mortem testing. This zone in Zavala County encompasses 22 properties.”

The second surveillance zone is in Washington County.

“Deer were antemortem rectal tested for release. This resulted in a single positive,” Reed said. “This zone in Washington County encompasses 555 properties. This large number of properties is due to the breeding facility’s close proximity to smaller properties located in the city of Brenham.”

The third surveillance zone is in Gonzales County.

“Deer were antemortem rectal tested to meet the requirements of a herd plan. Initially, there was one antemortem test positive, as well as two additional postmortem positives within the herd. An additional CWD positive animal has been found in this facility through postmortem testing. This animal, similar to the one found in Zavala County, was found to be not detected via antemortem testing only one and a half months prior to subsequently testing positive through postmortem testing,” Reed said. “This zone in Gonzales County encompasses 104 properties.”

The fourth and fifth surveillance zones are in Hamilton and Frio counties.

“Deer were antemortem tested for release. This resulted in one antemortem positive sample. This zone in Hamilton County encompasses 75 properties,” Reed said. “This final example here is in Frio County. A deer was postmortem tested and found to be positive. This zone in Frio County encompasses 27 properties.”

The commission is expected to consider a surveillance zone in Bexar County after a free-ranging deer near Hollywood Park tested positive for CWD. A zone is also expected in Sutton County after CWD was detected in a deer breeding facility there. Both zones will be discussed at the August commission meeting.

Additional changes
At the May meeting, the commission also approved a proposal that would allow CWD check stations outside of surveillance zones if there is not a suitable location for one inside a zone.

A provision would allow hunters to transport the heads of CWD susceptible species, like white-tailed deer, to check stations outside of surveillance zones when there isn’t one in their zone.

The commission also approved the removal of a sunset provision for the CWD surveillance zone in Duval County because the new CWD provisions allow for the removal of the zones if certain conditions are met.

The changes to the CWD surveillance zones will be reflected in the new Outdoor Annual when it is printed in the fall and the Outdoor Annual website before deer hunting season begins.