Chronic wasting disease: forgotten, but not gone


As an environmental journalist, I know full well how difficult it can be to get people interested in a creeping problem. Climate change is a perfect example—its effects are hard to pin down and slow to develop. Wildfire, on the other hand, is dramatic, deadly and easily identifiable as a problem, especially if your house burns down. Climate change news doesn’t break, journalists joke: it oozes.

Wildlife diseases are the same way. Those that dramatically wipe out entire populations—think white nose syndrome in bats or chytrid fungus in amphibians—garner much more media coverage than ailments like chronic wasting disease, which affects elk, deer and moose. CWD takes years to kill a single infected individual and has yet to completely decimate an entire herd. “I’ve heard it called an epidemic in slow motion,” says Christopher Johnson, a research biologist at the National Wildlife Health Center in Wisconsin.

Despite CWD’s slow pace, the disease isn’t going away: since being identified in captive mule deer in northern Colorado in 1967, it has spread to 19 states and in Wyoming, close to 40 percent of deer in the eastern half of the state are infected, up from 15 percent in 1997. One mule deer herd in particular has a 50 percent infection rate for males, the highest known prevalence in all of North America. Now, researchers studying that herd say they’re finally getting to a point where they can document how CWD slowly destroys an entire population, not just individuals. The preliminary findings aren’t good: the herd’s size has been cut in half in the past 12 years, and the drop seems to be related to CWD-induced deaths, says Melia DeVivo, a PhD student at University of Wyoming.

Yet there seems to be little general interest in CWD, and researchers say federal funding has decreased in recent years even as infection rates rise. “The negative effects aren’t in your face immediately,” DeVivo says, but “it is going to really hurt some of these populations if not completely wipe them out.”

CWD is a strange disease. It incubates inside infected deer, elk or moose for years before symptoms show up. The disease is carried by prions, an infectious protein that attacks the brain, which cause infected animals to lose their appetite. As they slowly starve, they begin to display : pacing, walking with their heads lowered, drooling and stumbling.

Because CWD takes so long to manifest itself, it’s difficult to manage. The state of and tried to kill off most of its infected deer, creating longer hunting seasons and requiring hunters to kill a doe before shooting a buck, but the disease still spread. That’s because says Johnson. They build up, and even amplify, in soil, infecting deer, elk and moose as they graze, and They linger in the feces and bodily fluids of infected animals and inside their carcasses after they die. Researchers are now studying whether other animals that eat the dead deer, like mice or voles, can get sick, too.

At the moment, the scientific consensus says even among people who eat contaminated meat. But that's still not a good idea, and many caution hunters not to shoot sick-looking animals and encourage them to minimize contact with brain and spinal tissues and get their meat tested. And according to the , “because of the long time between exposure to CWD and the development of disease, many years of continued follow-up are required to be able to say what the risk, if any, of CWD is to humans.”

I wondered how much hunters worry about the disease, so I called Susan Smith, owner of Paonia, Colo.’s wild game processing shop, to ask. We’re in the thick of hunting season in Western Colorado, and pickup trucks full of guys in camo or day-glo orange frequently rumble down the main street. Do people think about CWD, I asked? “A few do, most don’t,” she said, adding that hunters used to ask for their meat to be tested more often, but don’t as much anymore. Scott Edburg, assistant chief of the wildlife division at Wyoming Game and Fish, has seen a similar slump in interest among Wyoming hunters.

Why are people less concerned about CWD now, when it’s clear that infection rates are rising? “Cause they’re not reading about it in the newspaper every day,” says Michael Miller, senior wildlife veterinarian with Colorado Parks and Wildlife. “Part of the problem, to be quite honest, is we know it’s there, we kind of have this nagging suspicion that it’s having some effect, but it’s been really hard to point to something clear. And we really don’t have a lot we can do about it.”

Plus, previous efforts to control CWD were really unpopular. In the early 2000s, Colorado, like Wisconsin, tried to cull its deer population, but the public protested. “They didn’t see the clear effects of the disease on deer abundance,” Miller says, “but they saw the effects of our management on deer abundance.” After a few years, the culling stopped.

The most recent state to discover infected deer was Pennsylvania. Last March, according to , hunters turned a middle school auditorium “into a sea of camouflage” during a presentation from the state’s Game Commission about how to manage CWD. "There is no place where this disease has ever occurred that it has been stopped," said Walt Cottrell, a veterinarian for the Pennsylvania Game Commission. "There are two things the disease does when it arrives: It gets worse, and it spreads."

And, eventually, it fades into the background, like so many other creeping environmental problems.

Emily Guerin is a correspondent at NewTowncarShare News. She tweets @guerinemily.

Map courtesy

Photo courtesy

NewTowncarShare News Classifieds
  • The focus of this Regional Director of Development is to lead our major donor fundraising efforts in the Northwest, Northern Rockies, and Alaska regions. Reporting...
  • Surrounded by Idaho Panhandle National Forest. Handcrafted home, barns, shop, garage, fruit trees, gardens, greenhouse, hay, pasture, wetlands, at headwaters of year-round creek. $865,000. For...
  • Vaulted ceilings, two fireplaces, two bedrooms, loft, jetted tub, wifi. Forest, mountain views. Wildlife. [email protected]
  • NewTowncarShare News seeks a talented and motivated individual to provide help desk support and assist with larger IT projects. Ideal candidates will have prior...
  • The Conservation Lands Foundation (CLF) is a national non-profit organization headquartered in Durango, Colorado with offices in San Francisco, Albuquerque, Anchorage, Boulder, Las Cruces, Las...
  • San Isabel Land Protection Trust seeks an executive director who possesses fundraising experience and an interest in land conservation. The successful candidate will be comfortable...
  • NewTowncarShare News seeks a multi-talented visual journalist to join the team in rural Paonia, Colorado. Design magazine pages, find/assign great photojournalism for print and...
  • Home/horse property on 22.8 acres, pasture & ponderosa pines, near Mora, NM. Views of the Sangre de Cristo mountains. Near fishing, skiing, back-country hiking. Taos...
  • Position and application details online at, Apply by March 31, 2018 to [email protected]!
  • Our director is seeking to employ the services of an Accounting Clerk to assist with various accounting and administrative tasks. This is a great opportunity...
  • 3500sf, 4BR/4BA, 3-car garage, sun-room/deck, hot tub, evaporative cooling, solar and thermal PV, views, fireplace. By appointment (970)274-3251 or [email protected] Visit
  • Community Radio Project, Cortez, CO (KSJD & the Sunflower Theatre). Visit and click on the Executive Director search link. CRP is an EOE.
  • Valley, mountain and red rock views. City water and electricity at lot line. Five miles from Capitol Reef N.P.
  • University of Montana West Faculty Vacancy Announcement Department: Environmental Sciences Position: Full-time, academic year, renewable, tenure track faculty position Salary Range: Assistant Professor $46,000-$50,000 -...
  • WildEarth Guardians protects and restores the wildlife, wild places, wild rivers, and health of the American West. We seek a new director for our Wild...
  • Here is an opportunity to have a piece of self-sufficient paradise on Idaho's Main Salmon River adjacent to the largest Forest Service wilderness area in...
  • The most Relevant environmental novel of 2018, with The most unlikely heroine you will never forget.
  • Restoration Seeds is seeking a part-time manager to build our seed grower network & help cultivate our seed collection.
  • Friends of the San Juans is looking for a Staff Attorney to join our team.
  • Advocating for the Methow Valleys natural environment and rural character since 1976.