Columbia, Mo. — The pick-up trucks pulled into the parking lot every 10 minutes or so.
One after another, drivers rolled down their windows and staff greeted them like restaurant workers taking drive-thru orders. But these weren’t customers at any of the fast-food chains in central Missouri.
They were deer hunters. Successful ones, with freshly tagged white-tails, rolling into the Missouri Department of Conservation’s office in Columbia.
That mid-November weekend was the start of firearms season, typically, the most successful two-day outing for Missouri deer hunters. It was also when the state mandated sampling from every deer harvested in a select 35 counties.
Conservation staff were on the lookout for chronic wasting disease — a neurological illness that can infect deer and closely related species like elk and moose. It’s highly contagious, always fatal, and there’s currently no treatment or vaccine.
“In order to manage the disease, clearly you got to know where it is,” said Jason Isabelle, the state’s supervisor for deer management.
To limit the spread of CWD, wildlife agencies have often relied on deer hunters, landowners and other stakeholders. Many are willing to participate but tension has grown. Throughout the Midwest and Southeast, some deer hunters are at odds with their state over how to best respond to CWD.
That includes Missouri, where in addition to mandatory testing sites, the state had been working with landowners to “remove” deer in areas where CWD has been detected. But because the disease is not widely believed to affect humans, many hunters said they are more worried about the loss of game than CWD itself.
“You start hearing about the thousands and thousands of deer — healthy deer — that they're killing to try to thin the herds all through the state of Missouri,” said Mark Ackerson, a hunter from Peculiar, Missouri. “It starts to become a little ridiculous.”
As a lifelong hunter, Ackerson said he prioritizes harvesting wild game over store-bought meat. At a family outing this past season, however, he said there weren’t as many deer as he hoped.
“It has drastically affected my life,” he said. “Yeah, it's terrible and I don't believe in it.”
Rising pushback
The exact origins of CWD are unknown. It was first detected in captive deer at a government research facility in Colorado back in 1967.
Since then, the disease has been found in both wild and captive cervids in 36 U.S. states — including all 10 along the Mississippi River. It’s also been identified in five Canadian provinces, as well as Finland, Norway, Sweden, and South Korea.
Many states that have detected CWD have a surveillance or management plan in place.
“We know what happens when you let it run its course. Which is that it becomes highly prevalent and it has impacts on the population,” said Daniel Storm, a deer research scientist at the Wisconsin Department of Natural Resources.
But conservation agencies’ response to the disease has spurred distrust among some hunters. In Illinois and Minnesota, researchers have found that, particularly in places where CWD has been detected, hunters are less likely to defer to conservation agencies on questions like herd management and the risk posed by the disease.
In Missouri, one person started an online petition last year that called on the conservation department to end the “unnecessary killing” of deer as part of its CWD containment efforts. The petition implored MDC to consider more “sustainable and ethical” actions, as well as more engagement with the hunting community. It gathered over 3,000 signatures.
Then, in mid-December, MDC director Jason Sumners announced that the state would pause its post-season targeting of deer in areas where CWD had been detected.
In an open letter to hunters, Sumners shared how his passion for white-tailed deer as a youth in rural Missouri led him toward a career in state conservation.
Sumners said that MDC would work with both hunters and landowners to find a more sustainable approach toward CWD management. But he emphasized the threat of the disease if left unchecked.
“Some will say CWD is simply a political disease that has not impacted deer populations,” he wrote, “but this couldn’t be farther from the truth.”
Still, Sumners said that most stakeholders share the same goal of sustaining Missouri’s deer population so that future generations can appreciate it, including his own family.
“Together, we can preserve the health of the herd and the future of hunting; divided, we may lose it,” Sumners said.
Why the urgency?
Kip Adams is the chief conservation officer for the National Deer Association, an advocate for deer conservation across the country.
He said that CWD is the “single largest threat” to the future of deer herds and hunting opportunities in the U.S. So he wants to see the spread of the disease slow down.
“That's not just my personal opinion or [our] organization, but the vast majority of wildlife professionals view it that way,” Adams said.
CWD is caused by misfolded proteins, or prions. These replicate and damage the deer’s brain and nervous system, which often leads to extreme weight loss, drooling, confusion, and other strange behaviors that ultimately result in death.
Yet, CWD-infected deer can survive for a year or more before dying. They might not look sick at first, but these deer will still spread CWD through direct herd contact and bodily fluids, such as saliva, urine and feces. Shed prions can contaminate the soil and water for many years.
“By the time you're seeing lots of sick deer on the landscape, it's way too late to do anything,” said Isabelle.
Last year, Missouri tested over 36,000 deer for CWD, finding 243 new cases. Seven counties experienced their first-ever case.
New cases came out to less than 1% of the deer population tested in Missouri. It’s a good thing, said Isabelle. In some parts of states like Illinois, Wisconsin, and Nebraska, the CWD prevalence rate has surpassed 5%.
“At that point, from a management standpoint, there's really almost nothing that you can do,” he said.
Potential human risks
The Centers for Disease Control and Prevention recommends that people take precautions when handling animals infected with CWD.
Currently, there is no strong evidence that CWD can be transferred to humans. A 2018 article found a lack of transmission in macaque monkeys after 13 years of observation.
That’s unlike the prion-caused mad cow disease. It can spread to humans who eat infected beef and has been linked to fatal variant Creutzfeldt-Jakob disease of the brain.
Researchers did publish a 2024 article that examined two cases of hunters who developed Creutzfeldt-Jakob disease — which is different from the variant Creutzfeldt-Jakob linked to beef — after possible exposure to CWD-infected deer.
However, most research suggests a strong species barrier. In 2024, researchers in China and at the National Institutes of Health tested lab-grown human brain cells — called cerebral organoids — for potential transmission. The results found a lack of prion transmission, according to Dr. Cathryn Haigh, the chief of the prion cell biology unit and one of the study’s co-authors.
The results are “promising,” Haigh added. Still, concerns remain about both the emergence of a new CWD strain and the possibility that a small group of people has a genetic susceptibility to CWD.
“Personally, I would prefer my meat to be tested,” Haigh said. “But I really don't think that handling a deer carcass is probably going to be very high risk.”
The future of deer populations
In Missouri, the disease was first identified in 2012. Since then, it's been detected in more than one-third of all of the state’s counties.
Monitoring the spread of the disease can be a big endeavor. Missouri is home to approximately 1.7 million white-tail deer, and testing requires the willingness of hunters like Collin Masters.
On a warmer-than-usual season opener, Masters and his wife brought the severed head of a buck to the state conservation office in Columbia. She had shot the buck in Boone County, one of the places where scientists fear CWD may have spread.
The head was wrapped inside a plastic trash bag, which he had stuffed into a green cooler. It wouldn’t shut because the buck’s antlers were sticking out.
This wasn’t really an issue for Sarah Billington.
“He's making my life easy and I appreciate it,” she said.
Billington got to work with her scalpel. She is not a biologist. She’s an administrative assistant, whose responsibilities include paying office bills or answering questions from the public. Yet, Billington had performed this procedure at least 20 times already.
“When you work for the department, ‘other duties as assigned’ are a little weirder than most places,” said Billington.
Below the deer’s lower jaw were two bean-shaped lumps called retropharyngeal lymph nodes, which help its immune system filter out pathogens. Labs need the nodes because prions have a tendency to collect inside.
As a hunter, Masters said he cares a lot about white-tail deer. He also said there’s temptation not to comply with state regulations like mandatory testing in the current, post-pandemic climate.
“Politically, maybe people want to deny science a little bit and just get on with their lives,” said Masters. “I don't want to be the one who's going to just wait and find out later.”
This story is a product of the Mississippi River Basin Ag & Water Desk, an independent reporting network based at the University of Missouri in partnership with Report for America, with major funding from the Walton Family Foundation.
