The descriptions sound like a scene from a hunter’s horror movie. A deer staggers across a lawn, with unseeing eyes and drunken gait. Or maybe it is standing in a stream, drinking and drinking until it urinates but still will not stop, as if compelled to keep taking in water. Or it stands frozen in front of a house, staring, unable to fathom how to turn and go around its walls.
Basically: zombies, but make them deer.
Now imagine that before this final episode, the deer has seemed completely normal for more than a year, even though it is infected with the disease that will ultimately spell its doom.
The scenario isn’t hypothetical, although in Virginia it still remains fairly rare. For just over a decade, chronic wasting disease has been slowly penetrating white-tailed deer populations in the state’s northwestern counties, worrying wildlife officials who know the disease has no cure but hope to contain it as much as possible.
“There is not a known magic bullet that you can put into play and eradicate this disease or really significantly decrease transmission or spread,” said Megan Kirchgessner, the Virginia Department of Wildlife Resources’ wildlife veterinarian.
Since the first case of CWD was detected in Frederick County in 2009, state officials have recorded 108 positive cases in nine counties stretching as far south as Culpeper and from Shenandoah east to Loudoun. There likely have been more: because the symptoms of chronic wasting disease don’t appear until the final weeks of its progress, it’s difficult for researchers to identify possible carriers.
“Visibly a lot of these deer, they could look completely fine and still test positive,” said Ali Woodfolk of Hidden Pines Meat Processing in Madison. “Most hunters aren’t going to pull a deer out of the woods that looks bad.”
Hidden Pines is one of more than a dozen businesses and community groups that have been working with state wildlife officials in parts of Virginia where CWD has been detected to track its spread. In addition to conducting some sampling of carcasses, the processor collects and transfers deer heads to the wildlife department for testing. Last year, the Department of Wildlife Resources was able to collect 257 deer heads from voluntary dropoff sites throughout the CWD management areas, many of them just a refrigerator tucked at the rear of a country store.
“It at least gives them a baseline of what’s out there,” said Cyrus Baird, manager of government relations for Safari Club International and a Virginia hunter. Still, he fretted that 257 heads is “staggeringly low” in the context of all the deer hunted in Virginia annually.
“We’re pretty lucky here in Virginia that it’s pretty much relegated to four or five counties up in the northwest,” he said. “The main concern is it keeps creeping. It’s one county away from where I hunt.”
The slow march of prions
Outside of hunting communities, chronic wasting disease isn’t widely known. But the condition is part of a broader family of maladies known as prion diseases or transmissible spongiform encephalopathies.
The latter may be a mouthful, but it hits on the key features of these diseases. They can be transmitted from individual to individual. And they operate by attacking the brain; “spongiform,” according to the National Institute of Neurological Disorders and Stroke, “refers to the characteristic appearance of infected brains, which become filled with holes, until they resemble sponges when examined under a microscope.”
Prion diseases, which occur when a type of protein called a prion causes other proteins in the brain to fold abnormally, all cause neurological degeneration and eventually are fatal. Among humans they are also rare: Johns Hopkins University and NINDS estimate that only between 300 and 350 cases occur in the U.S. each year.
In humans, the most prevalent prion disease is Creutzfeldt-Jakob disease. A form that affects sheep and goats is known as scrapie. Elk, deer and moose can contract chronic wasting disease.
But by far the most widely recognized of the prion diseases is bovine spongiform encephalopathy — the “mad cow” disease that sparked such fear in the United Kingdom in the 1990s.
Much of the alarm over mad cow disease stemmed from its special ability to be transmitted to humans: scientists have mapped a link between the consumption of infected meat and the development of a variant of Creutzfeldt-Jakob disease. As of 2019, 232 human deaths worldwide had been linked to mad cow disease, most of them in the United Kingdom, according to the U.S. Food and Drug Administration.
“At this time there (are) no confirmed reports of chronic wasting disease being able to infect humans,” said Kirchgessner. But the ability of the bovine prion disease to leap species has led to an influx of research on chronic wasting disease, which like all prion diseases isn’t well understood.
Chronic wasting disease is also spreading and unlike other prion diseases is particularly difficult to contain because it impacts free-ranging wildlife rather than captive domestic animals. While scientists believe CWD can be spread through animals’ urine, feces and saliva, the proteins that cause the disease can also persist for long periods of time in soils and plants.
Today, CWD is found in at least 26 states, and infection prevalence in parts of Wyoming, Colorado and Wisconsin could be more than 40 percent, according to the National Wildlife Health Center within the U.S. Geological Survey.
In Virginia, the leading hypothesis for CWD’s appearance is that it spread from West Virginia.
“It had been detected for the first time just over the border in West Virginia in 2005,” said Kirchgessner. “We really increased our surveillance efforts.”
Four years later, the first Virginia case appeared in Frederick County. To date, the county remains the epicenter of the disease in the commonwealth, accounting for 80 percent of all cases detected.
Holding the line
Since then, state wildlife officials have attempted to slow the spread.
In the wake of positive cases, Virginia created disease management areas in which CWD had been detected or was suspected. The Board of Wildlife Resources forbid hunters from transporting whole carcasses or any deer’s brain and spinal cord — particularly dangerous vectors for transmission — outside their borders. Feeding of deer, which Kirchgessner compared to “pouring gasoline on a fire” during a 2019 public meeting in Culpeper, was prohibited in these areas as well.
“You are encouraging deer to come together, you’re encouraging healthy deer to mix with sick deer, and you’re really speeding up or amplifying … the transmission of disease from sick to healthy deer,” she told hunters.
The Department of Wildlife Resources also banned the use of natural deer lures made using animal secretions that could potentially transmit the disease. And it instituted certain mandatory testing days while amping up campaigns to encourage hunters to voluntarily test animals they killed and discard leftover parts in landfills where they would be less likely to act as a vector.
Testing has remained the heart of officials’ efforts. Regulatory changes sent out for public comment by the Board of Wildlife Resources this spring aim to further extend hunting seasons in management areas to not only reduce potentially infected populations, but also increase testing opportunities.
“We’re putting the best possible science to the actions that are being put before you,” Gray Anderson, chief of the department’s Wildlife Resources Division, told hunters in Culpeper in 2019. “Paramount” to the state’s efforts, he said, “is the persistence of a healthy deer herd and also the persistence of a tradition of deer hunting.”
“It’s literally just about containment and understanding where it’s from,” said Woodfolk. Still, she added, processors like Hidden Pines don’t have much guidance about what to do if a deer they process tests positive for the disease given the risks of prions being transmitted via contact with an infected carcass.
“From a business perspective, if we process a deer that’s positive, what’s our obligation? It’s pretty indeterminate,” she said. On an ethical level, she said Hidden Pines would feel obligated to notify other clients of the disease’s detection, but no state laws or regulations require them to do so.
As wildlife officials prepare to see the disease continue to push beyond its current borders, Baird is expecting an increase in another consequence that has complicated public health officials seeking to stem COVID-19’s spread: denial.
“There’s a not small portion of hunters out there who think it’s a conspiracy, who think it was made up by the insurance agencies or made up by game departments across the country,” he said. It’s an attitude that strikes fear in him: “I don’t want the collective hunting community or the deer herds in these states to be a fraction of whatever they are now because people didn’t take it seriously.”