Deer in 40 Missouri counties have tested positive for a fatal neurological disorder that could threaten the state’s deer population.
Chronic wasting disease, also called CWD or Zombie deer disease, first inhibits a deer’s ability to move, then leads to weight loss and erratic and listless behavior before eventually killing the animal.
In November, Texas County, south of Rolla, became the latest county to be added to Missouri’s chronic wasting disease management zone. A special five-day hunting season in those counties between Nov. 27 and Dec. 1 saw hunters kill more than 11,000 deer in an attempt to limit the spread of the disease.
Those efforts are working, according to the Missouri Department of Conservation, at least for now.
“So far this year we have 16 positive tests in 12 counties. That’s from hundreds of deer. The overall presence of the disease is in about 1% of deer,” said Jason Isabelle, the department’s deer and elk program leader. “It’s a lot worse in other states. Wisconsin is at about 50%.”
Missouri’s deer population is estimated to be more than 1 million. But it hasn’t always been that way. A general lack of conservation practices and over-hunting reduced their numbers to about 400 a century ago.
“I consider CWD to be a threat of that magnitude,” Isabelle said. “Even broader, a lot of people are saying it's one of the greatest conservation challenges that we've ever faced, too.”
If chronic wasting disease spreads, it could threaten Missouri’s deer population, which would hurt the state’s ecosystem and reduce hunting opportunities.
“The economy could be impacted, especially as you look at the small towns,” Isabelle said. “Hunting is big business, you know, for the restaurants, the hotels, retail stores.”
Hunting could also have an impact on food security for people in rural areas.
“You shoot one, two, three or four deer, it can certainly put a lot of meat in the freezer to feed yourself and your family,” Isabelle said.
Although it can spread to other mammals and create problems in the ecosystem, chronic wasting disease has not yet been shown to infect humans. Still, biologists and conservation officials advise against eating any deer that may be infected.
That’s because there is a concern that if left unchecked for long enough, CWD could mutate and be a danger to other livestock or humans.
A 2022 study of infected deer from the University of Calgary showed damaged proteins called prions that are responsible for the disease can spread across species.
“The barrier for CWD prions to infect humans is not absolute and that there is an actual risk that it can transmit to humans,” said researcher Sabine Gilch in her study. “From Mad Cow Disease, we know that prion diseases can jump the transmission barrier from animals to humans.”
Missouri plans to continue with its management program, even though it gets more difficult to manage every year as more counties are added.
“When you have more areas to work in, your resources are spread more thin,” Isabelle said.
