CWD control efforts could include deer removal
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Chronic Wasting Disease is spreading throughout Pennsylvania's deer populations and Blair County is near the center of infection, a Pennsylvania Game Commission spokesman said.
Unlike some diseases, which can be bacteria or viruses, CWD is a prion, or a misfolded protein, and can be spread through saliva, blood, feces and amniotic fluid, Game Commission Wildlife Biologist Justin Vreeland said.
While viruses and bacteria can have a relatively short shelf life, which makes disease management easier, prions can be potentially dangerous for years to cervids, mammals of the deer family such as deer and elk.
"It's not a living organism, and it doesn't have DNA," Vreeland said. "It can't be killed -- it can only be deactivated. Some studies suggest these prions can last for at least 16 years."
The disease has similarities to Mad Cow Disease and Scrapie, which affects sheep and goats. But scientists aren't positive what caused it, when it first appeared or if it can jump to humans, Vreeland said.
"No one knows how these prions originated or what made them mutate," he said.
Can be fatal
To make matters worse, the disease can be fatal, and there is no treatment currently available.
"It's a disease that affects the nervous system of the deer," Game Commission Game Warden Amy Nabozny said. "The protein causes holes in the brain, which causes a lot of neurological conditions."
Deer infected with CWD might not present visible symptoms for more than a year, Vreeland said, and the time from infection to death varies widely.
"How long the disease takes to kill an animal can depend on the health of the animal, to some extent the sex of the animal and also the dose they get," he said. "If a deer eats a stalk of corn covered in prions, it will get sick quicker than if it is exposed to relatively few prions, and it doesn't take many to infect the animal."
The Game Commission began surveying the commonwealth's deer populations for CWD in the '90s, but Vreeland said the agency didn't receive its first wild deer positive test until 2012 in Blair and Bedford counties.
Because of the communal nature of CWD, deer farms are havens for the disease, he said. A wild deer testing positive for CWD indicates a deer outside of a farm was infected.
Some speculate the disease originated on farms and transferred to wild populations when an infected deer escaped captivity and mingled with wild deer, but Vreeland said there is no substantial evidence this occurred in Pennsylvania.
With nearly 100,000 deer tested throughout the commonwealth, the game commission has only identified 453 cases of CWD in the white tail deer population and none in the elk population.
Without a vaccine, cure or treatment, the game commission is focusing on efforts to manage the disease and affected populations, Nabozny said.
"One of the things we're doing is regulating herd density to decrease the chances CWD will spread rapidly through high concentrations of deer in the area," she said.
The Game Commission is regulating population density through hunting seasons by combining buck and doe season for two weeks a year and increasing the number of antlerless licenses available in certain areas.
Deer management
"When it turns up in an area we didn't have it before, we can put in a Deer Management Assistance Program area," Nabozny said.
The DMAP program allows landowners to partner with the Game Commission, granting hunters permission to harvest antlerless deer on private land in certain surveillance areas where CWD has been identified. Once harvested, the hunters are encouraged to submit the animal's heads for CWD testing.
"From a law enforcement standpoint, we have bans on all feeding inside the surveillance areas," Nabozny said, explaining attractants are also prohibited. "Also, if you harvest a deer inside a disease management area, its high risk parts have to stay within the disease management area."
At least four disease management areas exist inside the commonwealth, with the largest covering most of Blair County and the counties east, west and south of Blair. So far, the management areas are mostly in the central commonwealth area.
Effectiveness vs. popular opinion
Despite the risks associated with CWD, not all the Game Commission's suggested methods of management have been well-received by the hunting community.
As the president of the Blair County Game, Fish and Forestry Association, Tim Merritts is familiar with the Game Commission's CWD management efforts as well as hunters' opinions of them.
Growing up in Blair County, Merritts has hunted deer near the Riggles Gap area most of his life. Despite being in a disease management area, he said he's never seen an infected deer in the area.
"Our association does a lot of conservation projects with the Game Commission," he said. "And, we've always had a good relationship."
While most of the approaches suggested in the Game Commission's newly minted management plan have been well received, Merritts said the suggestion to use "professional hunters" to cull certain populations ruffled some feathers.
"Hunters felt they should have the opportunity to thin the herds before the Game Commission brings in their sharpshooters," Merritts explained.
CWD Response Plan
In the July 2020 Game Commission CWD Response Plan, the Game Commission suggests using targeted removals in areas within containment zones. The Game Commission, however, also suggests increasing hunting opportunities in those areas.
"We're always going to give hunters the first opportunities to harvest the deer," Nabozny said. "If the population remains high in disease management areas after hunters had opportunities to harvest, targeted removal is an option that we may utilize."
Vreeland said professional removal might not be popular, but it is effective.
"We basically know that hunters -- through regulated hunting -- are not effective enough at reducing the population density to affect the disease," he said.
Even the most avid hunters only cull a few deer a season, largely because of limited freezer capacity for the meat, Vreeland said. In Wisconsin, game management agencies offered landowners and hunters a financial incentive to reduce deer populations as an alternative to targeted removal, but the program did not prove effective at reducing population density more than 50 percent, he said.
"A targeted effort is extremely effective to reduce deer populations with precision in designated areas," Vreeland said.
While hunters might disagree with some of the potential management efforts, Merritts said most people he's talked to are primarily positive about the management plan.
"They seem to be on the right track," he said.
Mirror Staff Writer Ike
Fredregill is at 814-946-7458.