Experts worry fatal brain disease could threaten Minnesota's $1B deer-hunting industry

Doug Duren is a hunter and landowner in the driftless area of Wisconsin
Doug Duren is a hunter and landowner in the driftless area of Wisconsin. He hopes to slow the spread of chronic wasting disease by providing plastic-lined dumpsters to dispose of deer bones. If left on the land, infected bones and guts can spread the disease for years.
John Enger | MPR News

It's been two years since chronic wasting disease was found in the wild deer herds of southeast Minnesota.

There's no cure for the brain disease and no vaccine. The life expectancy of a CWD-positive deer is about two years.

The good news is, it's still early in Minnesota. Only 20 wild deer have tested positive.

The bad news: It's hard to predict how the disease will spread in the state.

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And as deer hunting season gets underway this weekend, experts worry the fatal brain disease decimating deer in Wisconsin could explode in Minnesota and cripple a billion-dollar industry.

Hunters often don't want to shoot, or eat sick deer. If the disease spreads, that means fewer hunting licenses sold, and less funding for conservation.

This is a crisis Wisconsin knows well. What started as a fairly localized outbreak near Madison 16 years ago has spread across the lower third of the state. In certain areas, half the deer have CWD.

Bryan Richards.
Bryan Richards is the emerging disease coordinator for the wildlife division of the U.S. Geological Survey in Madison, Wis. It's like the Centers for Disease Control and Prevention for animals.
John Enger | MPR News

"We now have evidence that when CWD is there long enough, it impacts at the population level," said Bryan Richards, the emerging disease coordinator for the wildlife division of the U.S. Geological Survey in Madison.

Deer infected with CWD die young. Sick does will have fewer fawns over their lifetimes than healthy ones. Richards said it's probably happening already.

"We know this occurs," he said. "We know what the likely outcome of disease is."

This is what Minnesota can expect, he said, if something dramatic isn't done.

What went wrong in Wisconsin

Chronic wasting is a fatal brain disease to deer, elk and moose but is not known to affect human health.

In non-scientific terms, the animal's brain becomes like Swiss cheese. Within just a few years, a once healthy deer becomes skinny and confused, wandering around with strings of infectious drool running from its mouth.

Infected deer will likely die within two years. They are highly contagious while still alive, and research shows infected carcasses and gut piles left behind by hunters can leave infectious traces on plants which can contaminate other deer years later.

Minnesota has only two reported counties with CWD in the wild
Only Oldsted and Filmore counties in Minnesota have confirmed infected populations of chronic wasting disease in free-range deer. East of the Mississippi River, most of southern Wisconsin has infected populations.
William Lager | MPR News

The winter after CWD was first found in Minnesota, Michelle Carstensen and her team at the Department of Natural Resources launched a special hunting season around the infected area, hoping to reduce deer numbers. They even brought in federal sharpshooters and killed 1,400 deer.

"We were aggressive right away, trying to get additional animals harvested," said Carstensen, who runs the agency's disease management effort. "And basically try to define our area of infection."

It was a good start, and she wanted to keep going, but after just one year of intensive management, the effort petered out.

Her department ran out of money, and even if they hadn't, she said, land owners didn't want to allow sharpshooters on their property.

"There's very, very little public land in that area," she said. "So there's nothing we can do, without the explicit permission of that land owner. They have to be in agreement that it's for a good cause. "

Instead, she tried another special hunt, but that didn't work very well either. Even with nearly unlimited hunting tags for as little as $2.50 apiece — the cost of printing — locals just weren't interested in taking more deer.

"The truth is, at a certain point, it's not fun anymore," she said. "People have jobs."

The same thing went wrong in Wisconsin, on a spectacular level. Mike Foy had a front-row seat.

Foy is retired now, but when CWD was first found near Madison, he was a regional biologist for the Wisconsin DNR. The infected deer roamed his territory.

"It was February 2002," Foy said, while brewing coffee in his kitchen in Madison. "We were at a wildlife society meeting. Our veterinarian came in and told our bureau director. It was like the early days of HIV. No one really knew much about the disease, but there was a clamoring to do something."

At the time, CWD had only been found in a few western states, 800 miles away. People thought it was a slow-moving disease. Suddenly scared hunters and landowners were filling gymnasiums, demanding answers — demanding action.

Mike Foy thumbs through a box of his old files.
Mike Foy was a regional biologist with the Wisconsin Department of Natural Resources when chronic wasting disease was first found in the state. He thumbs through a box of his old files.
John Enger | MPR News

As Foy pours himself a mug of half-caffeinated coffee, he thumbs through a box of old files on the control effort.

He said that in the early days, the plan was pretty simple: the DNR drew a 13-mile ring around those first cases, and just tried to kill every deer inside it.

They expanded kill limits, hunting seasons and turned DNR staff like Foy into professional sharpshooters.

"Those were very strenuous years," he recalled. "We used to put in a time sheet every two weeks. And those are supposed to be 80 hours, for two 40-hour weeks. And we were routinely putting in 125, 150."

Mass killing is one of the only ways to stop CWD. The few remaining deer don't come in contact often enough to spread the disease. It's harsh, but it worked on a CWD-infected herd of reindeer in Norway.

But it failed in Wisconsin. It was hard, bloody work and expensive, and all that action people once clamored for turned out to be really unpopular.

Neighbors argued about CWD in grocery store checkout lines. Citizen groups were formed. People didn't want to sacrifice their deer herds for a disease they didn't know much about. They called their congressmen. Finally, the Legislature stepped in and halted the program.

Funding for CWD management and research has trailed off ever since. Today, very little is being done to slow the spread, and the result has been disastrous. Now the disease has infected untold thousands of deer. It's well established on the landscape.

A bounty as a solution?

In Minnesota, Carstensen is heading up a huge testing effort. Hunters in patches of northern, central and southeastern Minnesota are required to get their deer tested for CWD. The DNR is keeping tabs on the disease, but not doing a whole lot to stop it.

Carstensen said she wishes she'd spent more time on outreach when the disease was first discovered in Minnesota. And that's what she's doing now — aside from the CWD testing, she's running listening sessions and plotting out a more long-term plan to contain the spread.

Foy, the former Wisconsin DNR biologist, said, she's on the right track. But the goal shouldn't be to raise support for more sharpshooting. Instead, he said, Carstensen should try to mobilize hunters.

Since his retirement, Foy has been playing around with an idea. Build a highly accurate map of where CWD deer have been taken, he said, then offer a bounty for more.

"This would work best early on in an infection," he said. "Before the landscape got contaminated. Before you have thousands of sick deer."

In Wisconsin, he's proposed a $2,000 reward for sick deer. But there are a lot fewer CWD-positive deer in Minnesota. The odds of shooting one, even in an infected area , is low so he figures it would take more like $10,000 to motivate hunters.

This 300-acre farm has been in the Duren family for generations.
This 300-acre farm has been in the Duren family for generations. Doug Duren has changed the way he hunts on the property, hoping to slow the spread of chronic wasting disease.
John Enger | MPR News

If that sounds crazy, remember that Wisconsin spent millions on their sharpshooting effort. It cost roughly $10,000 per infected deer.

And if it still sounds crazy, Carstensen said it's on the table.

Richards, the CWD expert at the U.S. Geological Survey, didn't want to give Minnesota direct advice on chronic wasting management. Every state is different, he said, but there is one general rule with the disease — whatever is done about the disease, it has to be done as soon as possible.

That's because the faulty prions that cause CWD have staying power. Unlike a virus, or bacteria, there's nothing to degrade. It's just protein.

So, say a hunter kills an infected deer, and guts it in the woods. Inevitably a scavenger, like a coyote, will eat those guts, then travel 5 or 10 miles and relieve itself. The scat disintegrates in the grass over the next year, or maybe five. And after all that, if another deer eats that grass, there's a good chance it just contracted CWD.

Richards said that to control that kind of disease, Minnesota will have to do more than one year of sharpshooting.

A hunter changes his ways

Chronic wasting disease reached Doug Duren's family farm last year, in the driftless area of Wisconsin.

Since then, he's been working to slow the spread. He's tried a few different thing — most recently, dumpsters.

There's one just across the road from his farmhouse. It's lined with heavy grade black plastic, and there's something inside.

"It's a neck and a spine," Duren said. "By bagging it I'm kind of keeping the smell down a little bit, and also containing those infectious agents."

Because infectious CWD prions have staying power, hunters can't just leave guts and bones in the woods without risking more cases.

Duren raised money to put deer carcass dumpsters all around his area. He paid for this one himself to help out his neighbors, like the kid who brought over the first neck and spine of the year.

Doug Duren holds the skull of a CWD-infected deer.
Doug Duren holds the skull of the first chronic wasting-infected deer ever shot on his family farm.
John Enger | MPR News

"He came by and said, 'my dad says I have to do this now,' " Duren said.

The dumpsters cost a few hundred dollars. But that's nothing compared to the biggest thing Duren's done to fight CWD — change the way he hunts.

He leads me across the road to the family farmhouse, unlocks the door and shows me a sombrero hanging on his wall. It's huge and gaudy — and it came to symbolize bad hunting decisions.

Duren used to have strict thoughts on what that meant. For years, he made his hunting buddies wear the sombrero when one of them missed a shot, or killed a buck that was too young.

Like a lot of hunters, he managed the deer on his family's 300-acre farm for a certain type of hunt. He and his friends took a few does for meat, but let all the young bucks go. That way, they'd grow up and develop big racks of antlers, pass on those superior genetics and make the herd stronger. Then, near the end of their natural lives, Duren would finally take the shot.

And the strategy worked.

The walls of his trophy room bristle with antlers. They hang so close, the tines weave together like tree branches.

He points to a particularly large one. Beside it is a framed picture.

"How big was that deer?" he said. "Most guys stand behind them, and make them look bigger. I'm standing in front of it."

But after all these years and all those antlers, Duren now believes it he should have been wearing the sombrero. By only shooting massive bucks, he now knows he may have helped spread CWD.

Deer, he explains, behave differently based on sex and age.

"Think about it from the standpoint of having a cold," he said. "Say you go into a crowded bar, and you start dancing and hanging out."

It may sound like a strange analogy, but he explains further: An introvert might sit at the end of the bar all night, and not infect anybody. But say there's an extrovert at this bar and he has a cold. He'll dance all night, maybe take someone home. Maybe he'll drive to the next town and do it all again.

And pretty soon, everybody's sniffling, Duren said.

In the deer world, young bucks are those infected extroverts. They're most likely to spread the disease, and they like to travel.

So now, instead of letting them go while he waits for a big grandfather buck, Duren just kills the first buck to walk past his stand. They'll never grow massive racks of antlers. They won't give him bragging rights, or an adrenaline rush. But they won't get more deer sick, either.

For a hunter, the prospect of a giant buck is hard to leave behind. But as CWD becomes more common, Duren said, it's what more hunters might have to do.