A chronic pain for whitetails

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chronic wasting disease surveillance collection site
A chronic wasting disease surveillance collection site in Ohio. (Submitted photo)

In December 2020, Ohio confirmed its first chronic wasting disease positive wild deer in Wyandot County in northwest Ohio. It was a mature buck that was taken to a local taxidermist and was subsequently tested as part of routine CWD surveillance.

In January 2021, a positive yearling doe was harvested during a controlled hunt on the Killdeer Plains Refuge. Eight hunter-harvested deer tested positive during the 2021-22 deer season in southern Wyandot and northern Marion counties and one additional positive deer was removed through targeted shooting in March 2022.

Since that first positive, 49 wild deer in Ohio have been identified as having CWD, all in Allen, Hardin, Marion and Wyandot counties. Allen County’s first case of CWD was confirmed in November 2023. This concerning development of the disease’s expanding geographic on Ohio’s whitetail population continues to have biologists concerned.

During the 2023-24 season, 2,734 deer were tested and positive samples were found in Allen (1), Hardin (1), Marion (4) and Wyandot (21) counties. Testing was performed on deer harvested by hunters during the 2023-24 season, as well as on deer taken through targeted removal efforts in February and March. Postseason deer removal is meant to slow the spread of CWD by reducing deer numbers in areas where the disease has been detected.

Background

The disease was first discovered in the 1960s in the western U.S. It has currently been detected in free-ranging cervids in 29 states and three provinces and in captive cervid facilities in 18 states and three Canadian provinces. The total impact is 30 states and four provinces. The disease has also been discovered in Finland, Norway, Sweden and South Korea.

It is caused by naturally occurring proteins, labeled prions, which mutate, creating holes in the brain tissue. CWD is a proven death sentence to any infected cervid which includes whitetail deer, mule deer, blacktail deer, elk and moose.

As you would expect, both state and federal assets are being used to continue the study of this potentially herd-threatening disease. As is true of any investigation, a new twist in the plot can lead investigators in new directions. In the continuing work to unravel the CWD mystery, every avenue is being explored in the hope of discovering the silver bullet that may help limit its impact. Fortunately, the Centers for Disease Control and Prevention have continued to inform us that there’s no strong evidence that the disease is transmissible to humans.

Thankfully, there is a lot of brain-power keeping an eye on emerging and mutating infectious diseases like the various strains of the flu and the now all too familiar COVID viruses. Most of these bugs don’t tend to jump from one species to another, but it is possible. For instance, we do know that avian influenza can jump into the human population. The possibilities that other viruses may learn to do the same is what keep scientists awake at night.

Human impact

Unfortunately, prion-based CWD tends to be a “quiet” disease. Deer can be infected for a period of time (even years) before exhibiting symptoms. Since whitetail hunting is a major, recreational resource throughout much of the U.S., many hunters have questions about consuming venison that could be derived from an infected deer. You certainly can’t blame them for the concern.

During the mid-1980s and mid-1990s a different prion disease by the cartoon-inspiring name “mad cow” (bovine spongiform encephalopathy or BSE), proved to be no joke at all. That disease was found in cattle in the United Kingdom and several other countries, including the U.S. During that period, 178 people in the U.K. who were believed to have eaten infected beef developed a new form of a human prion disease, Creutzfeldt-Jakob Disease — and died.

This was of great concern to health professionals and extensive research into prion-based diseases has continued. In the U.K.’s mad cow cases, the vector was identified as feed that had been tainted with infected proteins. Once that identification was made, a solution to the issue could be aggressively pursued. Unlike mad cow disease, CWD’s prion-based structure has proven to be far more virulent, at least between cervids (whitetail deer, mule deer, elk and moose).

Like a scene from Frankensteinian plot, the National Institute of Allergy and Infectious Diseases scientists at Rocky Mountain Laboratories in Hamilton, Montana, have developed a human cerebral organoid model of CJD to evaluate potential treatments and to study specific human prion diseases. The created human cerebral organoids are small spheres of human brain cells ranging in size from a poppy seed to a pea. These organoids are grown in dishes from human cells. These three-dimensional miniaturized versions of specific organs or cells help simulate and give insight into the prion diseases and their effects.

Without getting into the nitty-gritty science that’s best understood by scientists and doctors, let’s review their basic results. The team of prion disease specialists conducted their study from 2022-23. They exposed the organoids to prions infected with CJD. The disease quickly infected the organoids. This was done as a testing or “proving” part of the methodology of the study.

Next, they exposed other human organoids to CWD prions from white-tailed deer, mule deer and elk. These human organoids were carefully observed for six months and none of the samples showed any sign of becoming infected with CWD.

That’s good news for hunters! There seems to be a strong species-based barrier preventing the disease from jumping from cervid to human. Of course, those doing the study still warn that handling carcasses possibly infected meats should be done so that direct contact with prions is avoided and that proper waste disposal be followed. They also acknowledge the relatively limited scope of the test and that “a small number of people may have genetic susceptibility that was not accounted for, and that emergence of new strains with a lesser barrier to infection remains possible.”

Sampling efforts

Sampling for CWD in Ohio continues in the 2024-25 deer hunting season as coordinated through the Ohio Department of Natural Resources Division of Wildlife. A disease surveillance area was established in 2021 to monitor the spread of CWD. Additional hunting opportunities and special regulations are in effect in the disease surveillance area, which includes all of Hardin, Marion and Wyandot counties as well as Auglaize and Jackson townships in Allen County.

As hunters, we each have a responsibility to act respectfully while in the field. This extends to other hunters and wildlife enthusiasts, the resources and game, the regulations and how we handle our harvests. Do not shoot, handle or consume any animal that is acting abnormally or appears to be sick. It’s advised that hunters to take the following precautions when pursuing or handling deer and elk that may have been exposed to CWD:

• Wear latex or rubber gloves when field dressing your deer or elk.

• Bone out the meat from your animal. Don’t saw through bone and avoid cutting through the brain or spinal column (backbone).

• Minimize the handling of brain and spinal tissues.

• Wash hands and instruments thoroughly after field dressing is completed.

• Instruments, cutting boards and other items used for processing should be soaked for 5 minutes in a 40% solution of household bleach to inactivate prions. However, the items must be completely clean with absolutely no tissue or organic matter present for this to be effective.

• Avoid consuming brain, spinal cord, eyes, spleen, tonsils and lymph nodes of harvested animals. (Normal field dressing coupled with boning out a carcass will remove most, if not all, of these body parts. Cutting away all fatty tissue will remove remaining lymph nodes.)

• Avoid consuming the meat from any animal that tests positive for the disease.

• If you have your deer or elk commercially processed, request that your animal is processed individually without meat from other animals being added to meat from your animal.

Contact the Ohio Division of Wildlife or one of its officers if you see or harvest an animal that appears sick. Call 1-800-WILDLIFE (800-945-3543) or visit ohiodnr.gov/discover-and-learn/safety-conservation/about-ODNR/wildlife/wildlife-contacts/county-wildlife-officers for a list of county-assigned Wildlife Officers.

“That’s the world out there, little green apples and infectious disease.”

—Don DeLillo

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