About Chronic Wasting Disease

Chronic wasting disease, or CWD (similar to “mad cow disease” in its effects), seemed to be the topic of the week during our time at the KOA campground in Wyoming. Son James, son-in-law Chris and I were there on our annual Antelope and Deer Safari a couple weeks back. (Scratch “Antelope” for 2018, as there were no antelope licenses available.) Interestingly, as we were preparing our white-tailed doe deer meat for trips back to our homes in Idaho, Colorado and Washington, traveling folks from Michigan, Wisconsin and Nebraska wandered over to chat.

Each of our three home states has specific regulations regarding the importing of wildlife carcasses from states with known/documented presence of CWD in wild cervids (deer family). Wyoming is one of those “documented” states. Thus, we were carefully preparing our made meat for transport. Idaho and Colorado allow import of whole quarters, or boned meat, but both ban or discourage transport of any bone containing brain or spinal tissue. Meat brought back to Washington must be entirely boned out. If any of us wanted to carry a skull back to our home base, it would have to be boiled and dried. To date, no CWD has been found in Washington or Idaho, and biologists aim to keep it that way. As the transportable portion of each carcass was properly prepared, it was bagged and put on ice in one or another cooler.

There seems to be a great deal of misinformation about CWD and the handling of wildlife carcasses, so I was struck by how knowledgeable our visitors were. We carried on some lively discussions about hunting and game meat and the blessings of each in our home states.

Still, given the large body of misunderstanding about CWD, and my role as chair of the Wildlife Disease Subcommittee of the Reecer Creek Rod, Gun, Working Dog and Outdoor Think Tank Benevolent Association, it seems that a primer is in order.

The USGS definition of CWD is “a fatal, neurological illness occurring in North American cervids…including white-tailed deer, mule deer, elk, and moose.” The USGS has the simplest (although CWD is a complex process) description of cause that I have yet found. “CWD is caused by a misfolded protein called a prion. All mammals produce normal prions that are used by cells, then degraded and eliminated, or recycled, within the body. When disease-associated prions contact normal prions, they cause them to refold into their own abnormal shape. These disease-associated prions are not readily broken down and tend to accumulate in – and damage – lymphatic and neural tissues, including the brain.”

The disease is transmitted directly and indirectly. It spreads through animal-to-animal contact and through contact with various environmental features – including water sources – which have been contaminated by infected animals (this could be from saliva, urine, feces, or even carcasses of infected animals). Several recent studies indicate that the prions passed out of deer and elk may be taken in by other cervids eating grass or other food plants growing in contaminated soil.

Visual signs of this wasting disease may take up to two years to appear after infection (animals will appear to act normally during the incubation period). Obvious signs are steady weight loss, decreased interaction with other animals and an apparent loss of fear of humans. As the disease progresses, observers report excessive salivation, and frequent drinking and urination. One challenge for biologist is that most symptoms of CWD have other causes as well, so early diagnoses have sometimes been off the mark and testing is indicated.

CWD was first discovered in 1967, at a Colorado wildlife research facility near Colorado State University. I know more about that facility than I wish to know, but that is another, sore, subject. Arguably, CWD spread from there. Today, CWD is of great concern to wildlife managers dealing with cervids anywhere, but especially those in the 23 states, two provinces, South Korea and Norway, where it has been detected. No treatments or vaccines are currently available.

To date, there is no evidence that CWD can be transmitted to cattle or humans. Still, precautions are always warranted. Obviously, we would not feed ourselves or family the meat made from a sick deer or one in very poor condition. We will certainly continue handling carefully those parts of carcasses in which prions accumulate – especially brains and spinal tissue.

Find out all you want to know about CWD at the end of a Google search for “chronic wasting disease.” The CWD Alliance (cwd-info.org/) has current information for each state and province.. For a list of states from which you may only bring boneless meat, click on the Washington part of the North American map, then see the question “Ban on Movement of Animal Parts?” (Or see wdfw.wa.gov/wlm/cwd/.)

Oh, yes. Our Wyoming hunt. Thank you for asking. It was very different this year from hunts in the previous 21 years in the area. Still, we had a great hunt. In fact, the boys noted that this actually was a more relaxed hunt than the last few. Can’t wait ‘til next year!

Happy hunting – and check your local meat import regs if you go out of state.