Targeted Hunts Were Supposed to Curb ‘Zombie Deer Disease.’ Now What?

In the middle of a spring afternoon near Lowden-Miller State Forest, Daniel Skinner poured a small pile of dried, yellow corn onto the ground.

Shouldering his .308 Remington rifle equipped with a thermal scope, he disappeared into a camouflaged ground blind in the middle of a cornfield. For eight hours, he waited for a white-tailed deer to approach the bait, hoping for a clean shot.

But the deer stayed away. At 10:30 p.m., Mr. Skinner, the forest wildlife manager for the Illinois Department of Natural Resources, called an end to the day’s culling and met up with several sharpshooters to compare notes. For that day, the tally was one deer among four groups. The same cull, a year ago, killed 10.

Over two decades, Illinois has been one of a number of states that have set up culling campaigns to slow the spread of chronic wasting disease, a strange illness that one expert likened to a “disease from outer space.”

“You would be hard pressed to come up with a disease, even if you were inventing one from scratch, that would be harder to manage than C.W.D.,” Mr. Skinner said.

But in mid-April, state officials decided to abandon the practice. The disease, they realized, had simply become too widespread.

“It’s harder and harder to throw troops at the front line,” Mr. Skinner said. “We’ve gone from one county to two counties to over 20 counties, and our staff has not increased twentyfold. We can no longer make a meaningful difference.”

‘There are no contingency plans’

Chronic wasting disease is a highly contagious, always fatal, rapidly spreading wildlife disease that has bedeviled wildlife managers in North America. It causes the deaths each year, directly or indirectly, of many thousands of white-tailed and mule deer. It infects all cervids — elk, moose, reindeer and caribou — and has been detected in at least 36 states, in Canada and in at least a half-dozen other countries.

Nicknamed the zombie deer disease, its symptoms are agonizing. As neurons die, brain function declines, and the animals slowly lose motor ability, resulting in stumbling, drooling and staring.

C.W.D. is one of a small group of known diseases caused not by bacteria, a virus or a fungus, but by a prion, an abnormal cell protein that causes healthy cells to misfold.

It has never been diagnosed in a human, but experts worry that it will become zoonotic, jumping the species barrier to infect people.

At least one prion disease, bovine spongiform encephalitis (commonly known as mad cow disease), has proved capable of crossing from animals to humans, though human cases have remained extremely rare.

First discovered in wild deer in 1981, chronic wasting disease has been shown to reduce infected deer herds by 3 to 20 percent a year.

The characteristics of prions complicate efforts to contain the disease. They last for years in the soil, absorbed by plants and persisting there.

Researchers are also worried that if the disease spread to species like cattle or hogs, it could endanger the food supply. Mad cow disease caused the deaths of some 230 people and led to a crisis in the cattle industry, as consumers lost confidence in the beef supply and sales collapsed.

A report issued last year by 68 of the world’s top experts on the disease urgently called for more funding and better surveillance to keep C.W.D. from contaminating the food supply and infecting humans.

“The bottom-line message is we are quite unprepared,” said Dr. Michael T. Osterholm, the director of the Center for Infectious Disease Research and Policy at the University of Minnesota, which prepared the report. “If we saw spillover right now, we would be in free fall. There are no contingency plans for what to do or how to follow up. It’s a slow-moving disaster.”

At a Senate hearing on Wednesday, Senator Raphael Warnock, Democrat of Georgia, criticized Health Secretary Robert F. Kennedy Jr.’s proposed budget cutbacks that include eliminating the prion disease surveillance program at the Centers for Disease Control and Prevention. Georgia alone has 600,000 hunters, the senator said, and their families would be most vulnerable through contact with infected animals.

Hunters have also been advised to avoid eating the meat of infected animals, even though the disease is mostly found in the brain and spine.

Besides culling, states have taken a variety of approaches to try to curb the disease: lengthening deer hunting season; increasing the number of deer that can be killed; requiring carcasses to be destroyed. Some allow more does to be hunted to control herd growth and to reduce the potential for mother-to-offspring transmission.

States have also banned the baiting of deer to keep them from gathering and infecting one another.

But so far, there is no known method for eradicating C.W.D. in the wild, “and that’s the problem,” Dr. Osterholm said.

The nature of prions may be evolving. For the first time, researchers were able to infect a mouse that had been grafted with human cells and tissues to mimic human physiology, Dr. Osterholm said.

Other experts are skeptical that the disease will leap to humans. In her lab, Cathryn Haigh, the chief of the prion cell biology unit at the National Institute of Allergy and Infectious Diseases in Hamilton, Mont., oversaw research that created organoids from stem cells to mimic human physiology. They then exposed these humanlike tissues to the disease, as a test for whether the disease was likely to jump the species barrier.

“We literally let them swim in C.W.D. prions,” she said. “They got the biggest exposure you can imagine tissue getting. They didn’t see any transmission. That suggests a very strong barrier, and in the real world, there are even more barriers.”

The $22 billion question

C.W.D. was first detected in deer in 1967 in captivity in Colorado and then in the wild in 1981, and it has been slowly spreading ever since. In March, it was discovered in two white-tailed deer in Gettysburg National Military Park in Pennsylvania.

Yellowstone National Park wildlife managers became concerned after an infected deer was found there in 2023, threatening tens of thousands of elk, deer and moose in one of the most wildlife-rich areas in the United States.

Some wildlife biologists believe wolves may reduce the incidence of C.W.D. by targeting many weak and sick animals, that are likely to be infected, something known as the predator cleansing effect.

Some experts suggest that deer hunting helps to limit the disease’s spread by reducing herd density.

Concerns have been voiced about how the spread of C.W.D. could have a serious economic impact. In many states, deer hunting is a multibillion-dollar industry. Direct spending nationally by big game hunters, mostly of deer, totals $22 billion a year.

“White-tailed deer are put up on a pedestal,” Mr. Skinner, the Illinois wildlife official, said. “For people that hunt, this is the No. 1 game species, and entire economies depend on the hunting of this animal.”

Annual events for deer hunters as well as taxes on equipment also contribute a great deal of funding for conservation efforts.

The issues of C.W.D. and how best to manage it have split the hunting community between those who are concerned about the illness, including some who have quit hunting, and those who think it’s a hoax of some kind. The rock guitarist Ted Nugent, an avid hunter and a gun rights activist, has assailed efforts to contain the disease.

“C.W.D. is a scam by untrustworthy, corrupt criminal bureaucrats that must be defied,” Mr. Nugent said in an email. “The only test that matters and has concluded that we kill millions of deer, eat millions of deer, and nobody has ever contracted C.W.D.”

Many in the hunting community, posting in online forums, share similar views.

But some are being careful. Alan Pierson takes official measurements of trophy deer for the Pope and Young Club, which gathers statistics on deer and other animals killed with bows. He said that he would eat meat that tested positive but took precautions to avoid cutting through bone and brain material.

“No human has ever got it, but I don’t want to be the first,” he said.