Slowing the Spread of CWD

By author of Brow Tines and Backstrap

We’re buying time for science to catch up and find a solution to a terrible disease

Scientists first learned of Chronic Wasting Disease in 1967, and it has plagued cervids ever since. Now it’s affecting how we hunt, butcher, and transport deer and elk. Even as we learn more about CWD, more cases continue to appear around the country. That’s why it’s important to understand how the disease is transmitted, and how you can help prevent it from spreading.

A group of biologists and technicians work with CWD test samples to help determine prevalence. (QDMA photo)

CWD at a Glance

CWD is caused by prions – misfolded proteins that can change other healthy proteins – which are spread through saliva, urine, and feces, and can remain in the soil and environment for years.

According to Heffelfinger, cases are increasing as the disease rapidly spreads to new places. CWD is now present in at least 26 states, four Canadian provinces, Norway and South Korea. In fact, the percentage of the cervid population testing positive in some Wyoming and Colorado units has increased 10-fold since the early 2000s. “About 70% of Wyoming’s deer hunt areas are positive for CWD,” he says. “More than half of Colorado’s deer herds are also infected, as are one-third of that state’s elk herds.”

Many other states show similar infection rates. And the trouble is, once a herd’s prevalence rate exceeds 27% (that is, more than 27% of the animals in a herd are CWD-positive), the herd’s population suffers, according to The CWD Alliance. And states without CWD management practices have positive test rates that exceed 40%. These are all scary statistics, and it doesn’t paint a bright picture for the future – especially when so many players are still ignoring practices that could help contain CWD.

The Spread of CWD, and Rumors

CWD is likely the single biggest issue impacting the future of our deer herds, says Kip Adams, QDMA’s director of conservation. Missteps only compound the problem.

“The outlandish claims by some that CWD is a hoax only hurt the entire hunting community,” Adams says. “This threat is real, and we need to hit it head-on. That will only happen when hunters believe, understand, and acknowledge the threat, and then work more closely with their state wildlife agencies. If we stop moving live deer and high-risk parts [brain, eyes, entrails, spine] of harvested deer, we can greatly slow its spread.”

In the past, state agencies moved wild cervids – especially elk and whitetails – during restocking efforts. Upon realizing this practice can spread CWD, however, most agencies curbed or ceased such activity. So, where haven’t we stopped transporting live deer and elk? In some states where high-fence operations are legal. Unfortunately, in many states, this practice is regulated by the Department of Agriculture and not wildlife agencies, which are generally more restrictive than the former.

“Human movement of infected animals can rapidly spread the disease long distances; so much so that it’s often joked that CWD spreads at the rate of 55 mph,” Heffelfinger says. “Some new discoveries, especially in captive facilities, can be traced back to the movement of animals from a known infected area."

But CWD isn’t just spreading via captive herds.

“There are other spots that show up without any evidence of captive deer being involved,” he says. “In most cases, they are spread by moving infectious material to a new area. That can be a deer in a trailer, or a spinal cord from a harvested deer in an endemic zone, or a [yearling male] deer dispersing [to its new home range].”

Some Northern and Western states have attempted to use wolves to manage this disease. Conflicting results abound, but there’s evidence to suggest wolves might do more harm than good by shedding consumed prions in their own feces.

“Wolf advocates want to ascribe yet another example of wolves saving the world, so they are inflating this idea of wolves controlling CWD, but there is no evidence they are or can,” Heffelfinger says. “The leading wildlife-disease experts say it isn't true and the advocacy NGOs suggest it is. Who should we believe?”

CWD has spread rapidly in the past two decades. (QDMA graph)

Fighting the Good Fight

The good news is, state agencies have implemented some policies that seem to reduce the spread. According to Adams, restricting the movement of live deer and high-risk parts is the first step. He also touts increased knowledge of engaged sportsmen and women, as well as increased lobbying and advocacy in Washington D.C., which ultimately produces more funding to help fight CWD.

While increased knowledge and funding is great, some of the more controversial measures ­– such as prohibiting the use of bait and outlawing natural deer urine – have drawn opposition from hunters. Targeted deer removal especially elicits heavy opposition from the masses in states like Illinois, Pennsylvania, Wisconsin, and more. Despite hunters who are unhappy with high harvest targets designed to control CWD, the strategy is being used.

Agencies are also ramping up testing of hunter-harvested deer. This helps determine prevalence and transmission rates, and it even identifies new areas the disease inhabits. In the past, post-mortem tests were the only means, but new Minnesota research shows live testing is possible and might soon join the fight.

Do Your Part

Government officials can’t fight this battle on their own, though. Protecting our deer and elk herds requires a joint effort with the hunting public to maximize efficiency. There are numerous ways hunters can help with that.

First, understand the CWD regulations wherever you hunt and wherever you live. And even if CWD hasn’t been found in the area, don’t transport carcasses. Instead, wear gloves while processing deer. Bone out the meat, and don’t cut or saw through bones, brain or spinal cord. Once finished, clean processing instruments with bleach. Wash your hands thoroughly once all carcass- and meat-handling is complete. Then, properly dispose of the carcass. Contact your state agency for correct procedures.

If you see a seemingly sick deer, report the animal to your state wildlife agency. After killing any deer, submit it for CWD testing. This increases the data set available to researchers, and also determines whether your deer has CWD. The CDC advises against eating venison from a CWD-positive deer. Even if your deer test negative, false negatives are possible. So don’t consume high-risk parts such as the brain, eyes, lymph nodes, spinal cord, spleen and tonsils.

Finally, remember that cooperation between hunters and state agencies is paramount.

“Support states when they want to reduce the spread and prevalence by changing deer and elk management,” Heffelfinger says. “That is not easy because the changes are going to be reducing deer densities, lowering buck age structure, and not having as many bucks on the landscape. That is going to take some sacrifice in some areas, but conservation is about sacrificing a little bit to gain the amazing resources we have available. Are we going to sit back and update maps and watch it spread, or are we going to try to slow it and keep it out of [new] areas?”

Some states, such as Pennsylvania, are establishing CWD sample drop-off stations for hunters. This provides additional data for agencies to work with and helps determine if harvested deer are CWD-positive, or not. (QDMA photo)

The Future

Researchers and biologists learn more about CWD every day. Recent developments (like the discovery that household bleach can neutralize the prions, and that new live tests are on the horizon) give us hope that we can contain CWD.

Despite all of the good news, however, the reality is we don’t yet have a cure and we may never have one. In the meantime, the best thing we can do is slow the spread. We’re buying time by containing the disease until we can find an adequate solution.

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