Wyoming Game and Fish identified seven new deer-hunt areas in 2014 where deer are infected with Chronic Wasting Disease, including one area within 40 miles of Yellowstone National Park.
The number is almost double the normal annual increase, but in line with historic trends when considering a two-year average, the agency said. Game and Fish identified no new deer hunt areas in 2013.
“Every year we detect CWD in two to four new hunt areas,” Game and Fish Wildlife Disease Specialist Hank Edwards said. “We’re average, if you combine the last two years.”
Chronic Wasting Disease, contagious, always fatal and with no known cure, affects the central nervous system of deer, elk and moose. It is a type of spongiform encephalopathy, a relative of Mad Cow Disease and Creutzfeldt-Jakob disease in humans.
CWD reduces animals to walking skeletons before death. It is among the factors likely responsible for the decline of deer numbers in Wyoming and dissatisfaction among hunters.
Infection of herds can have other implications for hunters. The federal Centers for Disease Control says hunters should avoid eating meat from infected deer.
Game and Fish maps show the disease is endemic among deer in more than half of the state — especially in the east and the Bighorn Basin.
The deer-hunt areas where CWD was detected include 116 west of Meeteetse. The western boundary of that hunt area is fewer than 40 miles from the world’s first national park. Deer hunt area 123 near Lovell also made the list.
In central Wyoming, new areas include 36 near Shoshoni, 160 near Lander and 97 near Muddy Gap.
Areas 98 and 84 were the final two areas identified. They straddle Interstate 80 west of Rawlins. (A WyoFile story last week misidentified one of the areas and a new area has since been included on the 2014 list.)
78 hunter-killed deer test positive
Game and Fish collected or received 1,335 samples by the end of November, according to an agency newsletter. From those, lab workers identified 78 hunter-killed deer as positive.
The wildlife agency’s testing — on both hunter-killed elk and deer — is focused at the frontier of the disease as it spreads slowly west. Area 116 near Meeteetse appears to be the closest to Yellowstone found so far, according to Game and Fish infection maps.
All but 160 at Lander are adjacent to hunt areas where CWD had previously been discovered in deer, according to a WyoFile review of Game and Fish infection maps.
In the southwest, a positive deer had been found earlier near Green River in hunt area 132. It appears to be the westernmost deer case discovered. West of the Continental Divide, a positive moose had been found in Star Valley.
Results for deer in 2014 are now final, unless a sample was misidentified and has to be reclassified, Edwards said.
“If you look on the bright side, this goes to show that our survey is working,” Edwards said. “We’re detecting where we’re expecting.”
“It didn’t show up in a location quite a ways from a known area,” he said. “There really weren’t any surprises so far.”
CWD is slow-spreading, he said, especially when compared to something like West Nile virus, which crossed Wyoming in about a year.
“Most diseases move much, much quicker,” he said. “We’ve had (CWD) in the state 30-40 years. It’s taken this long to get this far.”
Newly discovered infected areas are where CWD is expected, said Scott Edberg, deputy chief of Game and Fish’s wildlife division.
“The new areas for deer are adjacent to current areas so that’s not a big surprise,” he said. “In most of the new hunt areas the prevalence rates have been very low.”
Wyoming has been surveying for CWD for more than 20 years, he said. By the end of 2013 the state had tested 50,174 samples.
“I doubt there’s another state that’s come close to that,” Edberg said.
CWD, caused by a mis-shapen protein or prion, may not be present only in animals. The malady may have contaminated the landscape, said Lloyd Dorsey, the policy director for Wyoming Wildlife Advocates.
“This disease is likely in the environment as well as in animals,” he said. “There is a very important story being told.”
The latest announcements mean that infected deer, elk or moose hunt areas have been identified in 20 of Wyoming’s 23 counties, he said.
“To dismiss it as no big deal does a disservice to Wyoming citizens and all our wildlife resources,” he said. “It is a serious issue that should never be cavalierly dismissed.”
Two board members of Dorsey’s group filed a lawsuit last year challenging the elk hunt in Grand Teton National Park. The group also has criticized artificial winter feeding of elk west of the Continental Divide.
To eat, or not to eat?
The Centers for Disease Control has found “no strong evidence” of CWD transmission to humans. Nevertheless, “hunters and others should avoid eating meat from deer and elk that look sick or that test positive for CWD,” the federal agency says.
Game and Fish’s website also carries a warning; “human health agencies caution that known CWD-infected animals not be consumed by humans.” The website also says it is improbable that a person would be infected by eating meat from a CWD-infected deer.
“Thus far, there is no evidence that this is likely,” the website says. Hunters should wear surgical gloves when field-dressing an animal and avoid the brain, nervous tissue and organs.
Wyoming allows hunters who kill a deer that tests positive for CWD to dispose of the meat without being charged for wasting, said Scott Edberg, deputy chief of Game and Fish’s wildlife division. “They’re able to discard that meat and not be in violation of the law,” he said.
“I think it’s personal,” Edberg said of the decision to eat or discard meat from an animal that tests positive. “I probably ate some positive ones.”
There are a number of ways to get an animal tested, including turning a head into Game and Fish in the field. Testing may require securing specific parts of an animal, like a lymph node or blood sample. Some of the tests are free, others can be conducted for a fee of about $35, officials said. More information is available through the agency.
Artificial feeding is known to exacerbate the spread of diseases. Deer, elk and moose in northwest Wyoming “may be more at risk (to CWD) due to winter concentration of elk on feedgrounds,” Wyoming’s CWD action plan says.
That action plan will be revised this spring, Edberg said. The existing plan contemplates no “large-scale culling” even if CWD is found on a feedground. “Large-scale culling to reduce prevalence of CWD could have more severe effects on deer, elk and moose populations than CWD,” the plan states.
The plan needs regular revisions, Edberg said.
“We’re just trying to keep it current, keep it adaptable, especially on transmission — if there’s any way we can slow it down, prevent its spread,” Edberg said.
Game and Fish is reviewing the update internally before it is released for public comment. Today’s plan doesn’t mention predators as a potential solution to reducing the spread or prevalence of CWD, something Dorsey said is lacking.
“Having a functioning population of predators is an excellent tool against the increase or prevalence of a disease — as (is) not artificially concentrating large numbers of deer or elk,” he said. “Those are two tools they have right now — predators and allowing wildlife to spread out across the landscape.”
New elk hunt area also infected
In 2014 the agency also identified a new elk hunt area — 108 near Rawlins — where it found an elk with the disease. It is not contiguous to an already known elk hunt area where CWD has been discovered. There have been infected deer found or hunted in the area, however.
The elk discovery came as Game and Fish concludes its second year of testing an elk vaccine at its laboratory in Sybille Canyon between Laramie and Wheatland. The Canadian company Prevent provided the vaccine.
New York University developed a vaccine that prolonged the life of a handful of whitetail deer in a different study done by researchers there, with others. Vaccinated deer lived longer compared to unvaccinated deer infected at the same time. (Goni, et al. Mucosal immunization with an attenuated Salmonella vaccine partially protects white-tailed deer from chronic wasting disease, Vaccine 2014)
In Sybille, 40 elk are being studied, 20 of them control animals that get saline injections instead of actual vaccinations.
“The elk are naturally exposed to CWD in our facility,” said Dr. Mary Wood, state wildlife veterinarian. That means CWD is in the environment of the research pens at Sybille. There’s no known way to cleanse them.
Sybille “has had CWD since late ‘70s, early 80s,” Wood said. “We know our animals are exposed to a pretty reasonable dose.”
Researchers could have fed the elk CWD-infected brain material to ensure they were heavily exposed to the disease. But the goal is to test the vaccine in a more natural environment a free-ranging animal would be exposed to, Wood said. The elk test began in February, 2013.
“Only just now we have a couple of elk that are becoming clinical for CWD,” meaning it is now observable, she said. Regarding results, “it’s probably still a bit too early.”
The challenge in developing a CWD vaccine lies in the fact that the mis-shaped protein is a part of the elk. Unlike a virus or bacteria, it is “something the animal normally has,” she said. Except for its deformity.
“The body doesn’t recognize it as something foreign,” she said. It’s very hard to just target the one (protein) that’s misfolded.”
A vaccine that puts off infection for a time or that prolongs the life of a diseased animal may not resolve the issue, she said. A diseased animal that lives longer as a result of a vaccine might also spread CWD farther or for a longer time.
‘We still don’t know when an animal is shedding” diseased prions or proteins, she said. “There’s not a way to determine that at this point.”
Dorsey also cautioned against putting too much hope in medicine.
“I hope after years of a failed s19 vaccine for brucellosis in elk, people would look upon another silver-bullet vaccine with skepticism,” he said.
— This story has been corrected to reflect that the lawsuit challenging Grand Teton National Park’s elk hunt was filed by board members of Wyoming Wildlife Advocates, not the organization itself and that New York University developed the vaccine used in its own study – Ed.