Recent coverage in the Houston Chronicle and San Antonio Express-News calls CWD by another, more memorable name: “zombie deer disease.” But while some wildlife experts say it's a grave problem, not everyone agrees with the way CWD has been framed.
CWD is a transmissible prion disease, said Zach Tabor, a master’s student in geography at the University of North Texas who’s penning a thesis on CWD. Prions are neither virus nor bacteria; rather, they’re a folded, mutated protein. Other prion diseases include scrapie among sheep and so-called “mad cow disease” in cattle, Tabor said.
Deer infected with CWD become emaciated, and their coats may become ragged and fall away in patches, he said. They're also dealing with neurological issues because the disease creates holes in their brain.
“This deer’s going to be kind of acting like a zombie — like the ‘zombie deer,’” Tabor said. “That’s where that [term] comes from: They’re just stumbling around, standing, acting weird.”
Much like the novel coronavirus has become politicized, CWD is a hot-button issue among doe aficionados. The Texas Parks and Wildlife Department (TPWD) has been known to exterminate deer believed to have the neurodegenerative disease.
In one case, deer breeders accused TPWD of slaughtering $700,000 worth of their property, prompting a lawsuit.
Tabor said it takes roughly four years for a CWD-infected deer to die of the disease. During that time, they may travel quite a ways, shedding prions as they go.
Once those prions are in the environment, they don’t die like bacteria or viruses, he said. Rather, they sit around until another buck picks it up.
Texas’ wildlife department views the disease as a threat because other states, such as Wisconsin and parts of Michigan, have areas where 80–90% of the deer population has CWD, Tabor said. There’s really no way to change that, either — unless the area could be corralled and depopulated of deer.
“So, the state is doing its damndest to keep that from happening,” Tabor said.
Deer infected with CWD don’t pose a threat to humans, he added: They aren’t aggressive, and there’s no concern they’ll charge anyone. As of now, CWD doesn’t have an effect on people, but some fear that it someday could if the disease is left to spread.
Tabor said it’s similar to how researchers believe that mad cow disease wasn’t originally a human health concern, but that it ultimately grew to be one through exposure.
Many people don’t think CWD is consequential, Tabor said, but the “potential effects are much worse than the cure.” If Texas has a high population of CWD-positive deer, then the state will lose funds brought in for deer hunting. In turn, that creates a loss of conservation dollars, because hunting helps to fund conservation work.
“It’s a big deal, and if it ever became a human health concern, it’s unlike cattle: Deer are just kind of running around everywhere,” Tabor said. “So it presents a much bigger challenge and kind of a scarier situation.”
“When politics and science come together ... it creates all kinds of problems.” – James "Dr. Deer" Kroll
But not everyone agrees with the term “zombie deer,” including James C. Kroll, the director of the Institute for White-tailed Deer Management & Research. Known also by his nickname “Dr. Deer,” Kroll said PETA devised the “zombie” term, and the media have also run wild with the misleading name.
Kroll said CWD symptoms don’t track with those seen in a horror flick. Of the more than 83,000 deer tested for CWD in Texas, few were positive, and none have been known to die from it, he added.
To Kroll, CWD has been blown way out of proportion. There isn't a credible series of studies proving that CWD has damaged the deer population, he said. Conversely, there is published science that indicates it’s “very, very difficult if not impossible” for humans to contract it.
Since CWD was first discovered in 1967, people have eaten millions of pounds of venison without incident, he said. Concerned hunters can always get their game tested for CWD prior to consumption.
“So that all said, it’s not really that big a disease,” Kroll said. “But on the other side of that coin, it’s a huge political disease.”
There’s a lot of intensive, private, deer management here, including deer breeders, Kroll said. The presence of CWD may serve as motivation for more regulation.
CWD takes time to develop, but with white-tailed deer, herds “turn over” every 3.5 years, he said. If a female deer contracts it, she may have had multiple sets of fawns by the time she becomes clinical.
Plus, deer typically die of something else before CWD can claim them, Kroll said.
At the same time the state is attempting to eradicate CWD, he said there’s another, more concerning disease at play: epizootic hemorrhagic disease (EHD).
“The Bible says, ‘Saul has killed his thousands, but David has killed his tens of thousands. Well, Saul is CWD and David is EHD,” he said.
But Kroll does agree that the CWD ordeal has been highly politicized: “When politics and science come together — as we’ve seen with COVID — it creates all kinds of problems.”