‘Zombie deer disease,’ a.k.a. chronic wasting disease, heats up in Pennsylvania

Chronic wasting disease, which some want to label “zombie deer disease,” has been found again on private, captive deer operations in Pennsylvania.

The Pennsylvania Department of Agriculture recently announced that a doe on a Bethel Township, Fulton County, breeding farm, and a buck on a Bloom Township, Clearfield County, hunting preserve have tested positive for CWD.

Both farms will be under quarantine for 5 years, as will the Fulton County farm where the buck was purchased four weeks prior to its harvest on the Clearfield County hunting preserve, where it had been moved and released.

While neither of the deer showed signs of CWD prior to its death, both were born and raised in an area of Fulton County where wild deer have tested positive for CWD since 2015 and captive deer have tested positive since 2017.

The Bloom Township hunting preserve is just a few miles south of Pennsylvania’s southernmost elk management zone and about 25 miles south of Benezette, the heart of the Pennsylvania Elk Range.

CWD infects deer, elk, moose and all species in the cervid family. It is always fatal. There is no treatment for an infected animal and no vaccine to protect any animal.

It is spread through direct contact with saliva, feces and urine from infected animal or contaminated environment.

Most wildlife agencies are driven by hunter and hunted-game issues, and deer are the No. 1 most hunted big game species across North America, meaning the top worry in most states is the impact on deer and deer hunting.

In states with large elk populations and large-scale tourism based on those herds, like Pennsylvania, there is additional worry over the potential impact on a big chunk of economic activity.

Human impact?

Agencies involved in battling the spread and impact of CWD regularly note that the Centers for Disease Control and Prevention says there have been no reported case of the disease infecting people.

However, here’s what the CDC offers on its CWD website:

“To date, there have been no reported cases of CWD infection in people. However, animal studies suggest CWD poses a risk to some types of non-human primates, like monkeys, that eat meat from CWD-infected animals or come in contact with brain or body fluids from infected deer or elk. These studies raise concerns that there may also be a risk to people. Since 1997, the World Health Organization has recommended that it is important to keep the agents of all known prion diseases from entering the human food chain.”

The CDC also recommends that hunters take the following steps when hunting in areas with CWD, “to be as safe as possible and decrease their potential risk of exposure to CWD:”

• Do not shoot, handle or eat meat from deer and elk that look sick or are acting strangely or are found dead as roadkill.
• When field-dressing a deer, or handling the meat, wear latex or rubber gloves.
• Minimize how much you handle the organs of the animal, particularly the brain or spinal cord tissues.
• Do not use household knives or other kitchen utensils for field dressing.
• Check state wildlife and public health guidance to see whether testing of animals is recommended or required. Recommendations vary by state, but information about testing is available from many state wildlife agencies. (The Pennsylvania Game Commission recommends testing of deer killed in known CWD areas of the state.)
• Strongly consider having the deer or elk tested for CWD before you eat the meat.
• If you have your deer or elk commercially processed, consider asking that your animal be processed individually to avoid mixing meat from multiple animals.
• If your animal tests positive for CWD, do not eat meat from that animal.

Also on its CWD website, the CDC states, “As of January 2019, CWD in free-ranging deer, elk and/or moose has been reported in at least 24 states in the continental United States, as well as two provinces in Canada. In addition, CWD has been reported in reindeer and moose in Norway and Finland, and a small number of imported cases have been reported in South Korea. The disease has also been found in farmed deer and elk.”

Pennsylvania’s response

Pennsylvania became the 23rd state with a confirmed case of CWD on Oct. 10, 2012, when tests on tissue samples from captive deer on a New Oxford, Adams County, deer farm tested positive.

That led to the establishment of Pennsylvania’s first disease management area, which has since been eliminated.

Subsequent discoveries of CWD in Pennsylvania led to the establishment of 3 additional DMAs that remain in place: DMA 2, where CWD was detected in multiple free-ranging deer in Bedford, Blair, Cambria and Fulton counties since 2012, and captive deer farms in Bedford, Franklin and Fulton counties during 2017; DMA 3, where it was found in 2 captive deer farms in Jefferson County during 2014 and a free-ranging deer in Clearfield County during 2017; and DMA 4, where it was found in a captive deer at a facility in Lancaster County during 2018.

The CDC notes, “It is possible that CWD may also occur in other states without strong animal surveillance systems, but that cases haven’t been detected yet. Once CWD is established in an area, the risk can remain for a long time in the environment. The affected areas are likely to continue to expand.”

The CDC lists CWD as being caused by prions, similar to mad cow disease in bovines and scrapie in goats and sheep. Prions are “abnormal, pathogenic agents that are transmissible and are able to induce abnormal folding of specific normal cellular proteins called prion proteins that are found most abundantly in the brain. The functions of these normal prion proteins are still not completely understood. The abnormal folding of the prion proteins leads to brain damage and the characteristic signs and symptoms of the disease.”

That brain aspect of CWD has led some to refer to it as “zombie deer disease.”

Clinical signs of the disease include weight loss, excessive salivation, increased drinking and urination, and abnormal behavior like stumbling, trembling and depression. Infected deer may also allow unusually close approach by humans or natural predators.

An alternative approach

In another recent CWD development, Unified Sportsmen of Pennsylvania, which has opposed the deer management program of the Game Commission for at least the past 20 years, held a press conference February 4 in the Capitol Rotunda in Harrisburg to announce a fund-raising effort to support an alternative research approach to defeating CWD.

Most wildlife agencies and researchers believe prions are the cause of CWD and have been trying to understand prions and deal with their impact on deer and other animals. But Frank Bastian, clinical professor of neurosurgery and pathology and professor of veterinary science at Louisiana State University, has been researching a bacteria known as spiroplasma as the cause of transmissible spongiform encephalopathies (TSEs) such as CWD.

USP on February 4 announced a 3-year, $100,000 per year fund-raising effort to accelerate Bastian’s work on spiroplasma, which was described as “the real cause of CWD,” by John Eveland, a wildlife biologist often cited by USP.

He said, “within possibly a year,” the USP-supported project with Bastian will produce a diagnostic kit for hunters to use in the field to determine if deer they harvest have CWD. After 2 years, Eveland said, the work will produce an injectable vaccine primarily for captive deer and elk. And, in the third year, he projected there will be an oral or nasal vaccine for wild deer and elk.

The National Deer Alliance, a coalition of national organizations supporting hunter-focused conservation of deer across the U.S., was quick to respond to the USP announcement. The alliance issued a statement from Krysten Schuler, a wildlife disease ecologist and co-director of the Cornell Wildlife Health Lab, who also serves on the NDA board of directors:

“There is international agreement among scientific agencies, including the Centers for Disease Control and Prevention, that prions are believed to be the infectious agent that causes TSEs. Viruses and bacteria are not supported as potential causes of TSEs for a number of reasons, which include lack of an immune response, resistance to normal disinfection procedures, environmental persistence for years to decades, and intensive genetic study.”

The Game Commission and Department of Agriculture also responded to the USP announcement, explaining that the 2 agencies “would like to make clear that decades of research have provided abundant evidence that prions, or misfolded proteins, are the infectious agent of CWD, and this hypothesis is accepted by state agriculture and wildlife agencies across the U.S. While alternative theories exist, they have not been thoroughly researched.”

At the press conference, Pete Kingsley, USP treasurer, said the organization has donated $18,000 to the project and collected other donations ranging from $20-$33,000.

He commented, “The state game commissions across the nation have been trying to stop the disease by shooting the deer for the past 50 years plus and it has not been working, and it never will.”

Nixing a deer-reduction plan

In late January the Pennsylvania Game Commission announced a deer-reduction plan for a 100-square-mile area of Bedford and Blair counties as part of a pilot project with U.S. Department of Agriculture Wildlife Services to reduce the impact of CWD in a hotspot and to combat its spread.

Less than 2 weeks later the commission announced that it had not received “the necessary support from landowners” in the 2 counties to move ahead with the deer-reduction part of the plan.

Other phases of the project, including placing GPS collars on deer to study their movements and survival, will continue.

“And it’s hoped that, by next year, increased awareness about CWD and the threat the disease poses to deer and elk statewide will bring about the support necessary locally to begin the phase of the project that has been put on hold,” the commission said, noting that there could still be some “isolated targeted-removal operations in other areas where a solitary CWD-positive deer has been detected.”

“While the lack of access to private land is unfortunate, it could well demonstrate there is work to do when it comes to educating the public about CWD, and we will be ramping up our efforts to bring the facts about this disease and its potential impacts on Pennsylvania to light,” said Bureau of Wildlife Management Director Matthew Schnupp.

“As it is now, CWD has been detected only in a few parts of the state. Our pilot project in Bedford and Blair counties is being conducted where the problem is worst, but hunters in most areas of the state have not had to deal with CWD in the deer that they hunt, or abide by the regulations intended to slow its spread.”

Here’s more about chronic wasting disease in Pennsylvania: