Appearance of chronic wasting disease means changes to deer hunting, management
by Sydney Cromwell
Some people call it the “zombie deer disease.” Take one look at a deer showing signs of chronic wasting disease (CWD), and it’s easy to see why.
Deer with CWD often become thin and weak, with frequent tremors and drooling. They have trouble standing, moving around or even lifting their heads, and sometimes lose their fear of people, appearing almost tame.
After first being found in Colorado’s captive deer herds in the 1960s and wild deer in 1981, CWD has spent the decades creeping across the deer, elk and moose populations of North America. According to the Centers for Disease Control (CDC), it now exists in 28 states and two Canadian provinces, including the first known appearances in North Carolina and Alabama earlier this year. There have also been cases in Norway, Finland, Sweden and South Korea.
Chris Cook, who serves as deer program coordinator for the Alabama Department of Conservation and Natural Resources (DCNR) Wildlife & Freshwater Fisheries Division, said that from watching the growth of the disease in other states, the appearance of CWD in Alabama was almost guaranteed to happen eventually. And it did, with the first confirmed Alabama case in January and the second in March, both in Lauderdale County.
“You can do things to slow the spread and keep the prevalence rates low in areas where it is found. But it’s inevitable because of what causes the disease and how it spreads,” Cook said.
CWD is caused by prions, which are abnormal protein cells that cause brain and nervous system degeneration and death. Other examples of prion diseases include bovine spongiform encephalopathy (mad cow disease), scrapie (affecting sheep) and Creutzfeldt-Jakob disease (affecting humans). However, there has been no sign that CWD can be transmitted to humans or species like cows and sheep.
CWD spreads among deer and related species through bodily fluids, which carry the prions. These prions can stay infectious for a long time outside the body, meaning transmission is possible through shared food and water sources or even contact with infected ground.
Deer that are infected can take up to two years to show those “zombie” symptoms, which makes it harder to track and control the spread of infection.
In areas where CWD has been present for decades, the CDC has reported some wild deer and elk populations with infection rates of 10-25%.
“Long term with the deer population, states that have had it for 20-plus years, some of them are just now starting to see some localized population declines that they’re attributing to CWD,” Cook said.
He said Alabama began monitoring for signs of CWD in 2002. After the first cases appeared in Mississippi and Tennessee in 2018, the DCNR began to step up that work.
“That put it within 50 miles of some of our counties, … so we really ramped up our surveillance efforts in those counties especially,” Cook said.
Monitoring is primarily done through testing lymph nodes in the heads of deer that are submitted by hunters for testing, or from deer reported by the public for unusual behaviors or manners of death, Cook said. The department tests some roadkill as well, he said.
Along with surveillance, Cook said the DCNR established regulations about moving certain deer parts from other states, in case CWD accidentally hitched a ride from a positive population. It is illegal to transport a whole deer carcass from another state into Alabama, as well as soft tissues like the brain, spinal cord and antler velvet. Natural deer urine, used to attract deer, also cannot be imported from other states.
If properly processed, hunters can bring back the following prizes from their out-of-state hunting excursions: completely deboned meat; skull caps and antlers, cleaned of any brain or spinal matter; upper canine teeth, cleaned of soft tissue and root structures; raw capes (the hide from the nose to the front shoulders), cleaned of any brain or spinal matter; tanned hides; and finished taxidermies.
“It took it four years to travel 50 or 60 miles. I’ll take those odds. It travels slowly unless someone transports it accidentally,” said Chuck Sykes, director of the DCNR Wildlife & Freshwater Fisheries Division.
As CWD gradually made its way through the Southeast, Cook said the DCNR created education programs to teach hunters and the general public about the dangers of the disease and the control measures the state had put in place to stop it. Sykes said the department also learned from the experiences of other states in managing the disease.
“We’ve been able to take what other states have done and put Alabama in as positive a position as it can be,” Sykes said.
After two decades of monitoring, the first positive case of CWD in Alabama was announced on Jan. 7, 2022. The deer had been harvested in west-central Lauderdale County and submitted by a hunter for sampling.
For the remainder of the season, which ended Feb. 10, the DCNR enacted a CWD Management Zone in Lauderdale and Colbert counties to get a grasp on how far the disease had spread, and rein it in where possible. Within those counties, the area enclosed by Highway 43, the Tennessee River and the Tennessee and Mississippi state lines was designated a “high-risk” zone, while the surrounding land was considered a buffer zone.
Cook said that the high-risk zone was “basically treated like another state.” Any deer killed within the zone could not be brought into the rest of Alabama unless it met the criteria for proper cleaning and processing.
There was also a ban on feeding or baiting wildlife within the zone (except for bird feeders and feral hog traps) to discourage groups of deer congregating in large amounts and potentially sharing CWD. In some Western states, feeding programs that have maintained elk populations are now causing concerns about disease transmission.
With the hunting season nearly over, the DCNR also chose to get rid of bag limits for does and bucks within the CWD Management Zone, on both public and private land. The department required hunters to submit all carcasses from the high-risk zone for CWD sampling, and it was strongly encouraged for hunters in the buffer zone to do the same.
“We were trying to get as much data as we could during that 30-day window to help our decision-making going forward,” he said.
In that time, Sykes said the department tested 966 deer carcasses. Cook said that many hunters had questions about the new rules — including some with the mistaken belief that the removal of bag limits was an attempt to eradicate the deer population within the zone — but they were generally willing to comply.
“It helped the hunter out and it helped the department out,” Sykes said.
This increased testing turned up only one additional case, announced in early March.
“Right now it appears to be fairly well limited to a certain part of Lauderdale County … but we’re still in the early days,” Cook said.
“We are not going in and shooting deer this summer,” Sykes said. “… We found one deer out of the next 900 samples, so our prevalence rate is very, very, very small.”
Public education about CWD will also be an off-season priority, Cook said.
And when the new season begins, Cook said hunters can expect white-tail deer hunting to look much like it always has. The emergency rules that marked the last month of the 2022 season within the high-risk zone have not been proposed for next year, he said. There will be the same rules about bag limits for north Alabama (three bucks per season, one doe per day) and the same rules about transporting carcasses.
However, Cook said feeding wildlife will likely be banned again within the high-risk zone. The DCNR is also planning mandatory sampling weekends at a few key points throughout the season, when hunters will be required to get their deer carcasses tested for CWD through mobile sampling sites, drop-off freezers or Wildlife and Freshwater Fisheries Division offices.
He also encouraged testing even for hunters who aren’t near Lauderdale County. The more samples the DCNR has, the better it can track CWD across the state.
Between now and the start of the next season in the fall, Sykes said the DCNR biologists will primarily continue CWD monitoring through reports of roadkill or unusual deer behavior. With only two cases found so far, he said there isn’t a need for additional off-season monitoring efforts.
While there have been no cases of CWD infecting people, the CDC recommends that hunters should wait for the results of those tests before consuming any venison, particularly from the CWD Management Zone, and discard any meat from deer that appear sick or test positive for CWD.
In the short term, Cook said it is “business as usual for deer hunters” in Alabama despite the arrival of CWD.
“It’s not the end of deer hunting. Deer hunting will continually be a big part of what we do in Alabama,” he said.
CWD’s effects will most likely not become apparent until a decade or two down the road, Cook said, causing shortened lifespans and smaller populations. But the future for Alabama’s deer is hard to predict because so much will depend on how far — and how quickly — the “zombie deer” disease spreads.
“It’s not like a lot of wildlife diseases where there’s a sudden and drastic change to populations. It spreads slowly,” Cook said. “… We’re lucky that it’s slow to spread, and through management we can slow it even further.”