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Forrest Keizer, top, and Cole Hansen herd a cow elk infected with chronic wasting disease into a laboratory at the Wyoming Game and Fish Tom Thorne/Beth Williams Wildlife Research Center in Sybille, Wyo. NEWS&GUIDE PHOTO / CORY HATCH

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This is the first in a two part series – eds.

Outside a laboratory at the Tom Thorne/Beth Williams Wildlife Research Center at Sybille near Laramie, there’s a clattering of hooves against steel.

A small black-and-white security screen shows a 400-pound female elk barreling down a corridor of corral panels toward us. She charges into a small pen and she stands there – eyes bulging, mouth foaming and teeth clicking in agitation.

She is doomed, infected with chronic wasting disease, similar to mad cow disease, that affects ungulates like deer, elk and moose. She is one of two remaining elk at Sybille from a herd that Wyoming Game and Fish researcher Terry Kreeger intentionally fed ground-up deer brains to learn more about how the disease spreads.

Spreading is one thing Kreeger is certain about when it comes to CWD. Scientists say the disease is headed to Jackson Hole.

Since the mid-90s, when researchers first diagnosed CWD as endemic to the southeast corner of Wyoming, surveillance efforts have tracked the disease as it inched its way west across the state. Kreeger and his colleagues agree, it’s only a matter of time before CWD finds its way to 23 winter feedgrounds in northwest Wyoming, including the National Elk Refuge.

What happens then is hotly debated. Cousins to chronic wasting disease – including mad cow disease, Creutzfeldt-Jakob disease and Kuru, to name a few – have caused panic in international livestock markets and led to human deaths in the United States and abroad. Though scientists have never linked CWD to human illness, nobody is certain how hunters will react to an outbreak.

Some say that the disease is a ticking time bomb that will obliterate the Jackson and Sublette elk herds, along with the hunting and tourism industries it supports. Others contend chronic wasting disease is a minor nuisance that hunters, managers and wildlife watchers will learn to live with.

What’s certain is that it is incurable, is extremely difficult to exterminate from the environment, and brings a slow and cruel death. Like the one that will eventually overcome Kreeger’s Sybille test case.

What is now a temporary agitation will eventually become uncontrolled and persistent, even when she’s not being herded, penned and pricked with needles. The agitation is one behavioral symptom of a progressive degradation of her brain cells.

Inside her brain, mis-folded proteins called “prions” in her brain undergo a sort of chain reaction that causes cells to die. If you could somehow poke your finger through her skull to touch her brain, it wouldn’t feel firm like cauliflower, but soft and spongy where holes formed in the gray matter.

Outward signs of the disease include a gradual loss of body condition and a tendency to avoid other animals. Often times, the infected elk will become listless and nervous. Infected animals begin salivating, grinding their teeth and walking in set patterns.

Just before the animal dies, it will begin drinking and urinating excessively. Most die within several months of the onset of symptoms, often from pneumonia.

Researchers first described the brain changes associated with chronic wasting disease in captive mule deer in the late 1960s, and chronic wasting disease at wildlife research facilities in Colorado and Wyoming, including Sybille, in the 1960s and 1970s. Researchers aren’t sure if the disease originated in these facilities or, more likely, was brought in from the wild and spread more evidently in crowded conditions.


Researchers’ wild discovery

In 1981, researchers found CWD in free ranging elk in Colorado.

Sybille researchers Thorne and Williams led early research efforts until the husband and wife team died in a car accident in December 2004. The research facility was subsequently named in their honor.

Since, the CWD has appeared in wild and captive populations of ungulates throughout the United States and Canada, including Wyoming, Colorado, Utah, Nebraska, Wisconsin, West Virginia and Saskatchewan, Canada. It has not been found on a feedground. In 2006, Kreeger documented the first case of a CWD-infected moose.

How the disease spreads is one question among many. Researchers don’t know where it comes from. They don’t know if genetics plays a role. They don’t know a good test for it. And, they don’t know how to stop it.

What they do know is that these diseases, collectively called transmissible spongiform encephalopathies, represent something entirely new: They aren’t bacteria or viruses, they persist in the environment for years, they survive most modern sterilization techniques, there is no cure and they’re always fatal.

The closest it’s come to feedgrounds in Jackson is hunt area 120 near Thermopolis, roughly 100 miles as the crow flies. Wyoming Game and Fish detected the disease there in three deer in 2005. From there, it’s a short hop north of the Wind River Range, through Dubois and down into the Gros Ventre drainage to the Alkali, Fish Creek and Patrol Cabin feedgrounds, operated in winter. That’s only a few miles more to the National Elk Refuge where, last winter, more than 8,000 elk from the Jackson Herd spent months feeding on doled-out alfalfa pellets.

Not only could a single infected elk or deer conceivably migrate the distance from Thermopolis to Jackson, but according to National Elk Refuge biologist Eric Cole, the animals from these regions mix.

“Elk radio-collar data suggests that there is significant interchange between elk that winter in the Gros Ventre drainage and elk that winter east of the Continental Divide,” he said in an e-mail. “And ... there is also significant interchange between elk that winter in the Gros Ventre on state feedgrounds and the National Elk Refuge.”

Kreeger says the disease is slow spreading and a feedground infection inevitable.

“You will not stop this disease,” Kreeger says. “Once it’s established, nobody in North America has been able to stop it.”

Especially devious, the malformed prion persists in the soil for years, all the while retaining the ability to infect even without animal-to-animal contact, Kreeger says. That nightmare was proved in a Colorado lab.


Eliminating the disease

In 1985, during one attempt to eliminate the disease at a CWD-infected wildlife research facility in Fort Collins, researchers not only killed all their deer and elk, but soaked the ground with chlorine solution, removed roughly a foot of topsoil, applied more chlorine, and let the facility sit empty for more than a year.

When researchers reintroduced 23 elk to the facility, 17 percent came down with chronic wasting disease despite the attempts to eradicate CWD from the holding pens.

Researchers think chronic wasting disease can survive in the environment, retaining its ability to infect animals, for years depending on the type of soil. This persistence has important implications for places like the National Elk Refuge where large numbers of infected animals could shed the disease year after year, causing it to accumulate in the environment.

According to Cole, there is no practical way to remove the prion on a such a large scale.

“Elk may be infected for 18 months to several years without showing clinical symptoms of the disease,” he said. “During this time, they are likely shedding prions into the environment and potentially infecting other elk.”

Just how the disease will affect feedground populations is uncertain. Where the disease is endemic, CWD typically infects between two and five percent of a wild, free ranging elk population, according to Kreeger. But infection rates jump considerably in captive situations like game farms.

Cole and Kreeger say there’s no good data to show how chronic wasting disease would behave on a feedground. However, one good proxy to CWD’s potential infection rate should it reach the National Elk Refuge could be Rocky Mountain National Park.

There, elk winter in artificially high densities and CWD prevalence is around 11 percent. At least one study suggests that an elk population would start to decline once the infection rate reaches about 5 percent.

Still, Kreeger says he isn’t worried.

“Most scientists that are familiar with CWD would not say that CWD on a feedground would be devastating,” he said. “In the wild, we’re not seeing any population declines.”

Part of the reason for Kreeger’s confidence is the fact that even captive elk can live with CWD for seven years, during which time they can still mate and give birth to calves.

“I see the concern for it in many places diminishing,” Kreeger said. “We’re pretty sure that it doesn’t affect domestic animals. There’s increasing direct and indirect evidence that CWD does not affect humans.”

“What are the effects on a wildlife population?” he continued. “That’s kind of the last remaining question. It’s been in this country for 30 years. The mathematical models would indicate that we should be seeing population declines. We are not.”