Every five years, Colorado Parks and Wildlife operates a “Mandatory Monitoring Station” to survey healthy deer and elk for the prevalence of Chronic Wasting Disease (CWD). This year, deer are being monitored, and locally that’s at the intersection of highways 145 and 141; next year elk will be monitored.
What is CWD?
CWD is a “prion” disease, and according to the CDC, prion diseases happen when normal proteins in the body “misfold” and cause illness, impacting the brain. Prion diseases are rare, but they are always fatal. Bovine species have a version, “mad cow disease,” or bovine spongiform encephalopathy.
CWD, first identified in Colorado Springs in 1967, has since spread to 32 states and five countries. There’s no cure and no vaccine for it. Besides deer and elk, it affects moose. There are, however, some deer that are resistant to the disease, giving officials hope of natural selection or selective breeding to minimize CWD’s spread.
Alyssa Kircher, CPW terrestrial biologist, admitted there’s nothing positive about CWD. She said the bright side is that monitoring is in place with newer technology. CPW also shares data with the state of Utah, which has a voluntary testing program.
How does it spread?
Will Spence, CPW wildlife technician, said CWD spreads like the common cold. It’s through saliva, phlegm and eye moisture. It’s also spread by feces, and prions can be infectious for many years on the ground. Apparently, salt licks are a problem for spreading CWD, as is the feeding of deer. The disease is also transferrable through bucks fighting, because of the close proximity.
Spence said there is a higher prevalence of CWD in animals who congregate around agricultural and urban areas. The private hunt harvesting in local populations, however, has been effective in controlling CWD and has been supported by ranchers.
Spence said there’s a "species barrier,” though, and infected populations cannot spread it other species. For example, there is no known case of a human contracting CWD. Spence said mountain lions who were fed meet of animals infected with CWD have not shown any sign of infection. Mountain lions also target weaker animals, which could help control the disease.
What one local doctor says
Dr. Jim Evans, DVM, who lives in Redvale, has studied agriculture and animals for decades. He said in 60 years the disease has spread from one herd to half the country.
“The only nice thing is science is in our favor, and there is no spread across species,” he said.
Evans, originally from Pennsylvania, saw CWD there. Raising captive deer became a very profitable venture for some until the disease got into herds, and many of the deer farms had to euthanize.
He said eradicating any disease is hard in the wild, even rabies. Even if there were a vaccine for CWD, it would be hard to treat wildlife. He said it’s different in the cattle industry, though, and the beef market has seen changes, since a single cow’s life can be tracked from feedlot to table. In this way, any illnesses can be curtailed. That’s not possible with wild animals, however.
Hunters are helpers
Tony Bonacquista, CPW District Wildlife Manager, said hunters play a key role in wildlife management and tracking CWD.
“The technology is developing, but there is no way to get disease prevalence data from live animals,” Bonacquista said. “Hunters naturally choose healthy animals, and those harvested animals are the ones we need to check. We have mandatory checking of deer and elk every five years and will be able to compare this year’s numbers to the baseline prevalence of CWD five years ago. If we find ‘hot spots,’ we can look at environmental factors.”
He said hunters will be informed of any positive tests for CWD. It is recommended that any deer carcass testing positive for CWD should be disposed of at a land fill. Bonacquista added if the public sees a sick animal that needs put down, they should contact CPW. Illness testing may occur, but not always for CWD.
