September 19, 2018
By Reid Vander Veen
Ask around the hunting community about CWD lately, and you're sure to stir up a colorful conversation. Is it the epidemic that will forever change the hunting landscape or an issue that's blown far out of proportion by media hype and misinformation? Unfortunately, due to the amount of conflicting information available, finding a stance on the issue that's easy to understand has been anything but simple for many bowhunters.
As is common today when information can be spun and data can be manipulated to support whatever side of an issue one wishes to argue, when even science appears to contradict itself, we're left to sift through the information and draw our own conclusions. Here's a look at what you need to know and the two sides of the CWD argument.
What We All Agree On The history of CWD dates back to the 1960's when it was first discovered in a captive deer herd at research facilities run by Colorado State University (CSU) and the Colorado Division of Wildlife (CDOW). It wasn't found in free-ranging herds until the 70s and even then it was only found within close proximity to the infected research locations in Colorado and Wyoming. Through both natural migration and the intentional transfer of animals the disease now impacts at least 24 states, 3 Canadian provinces, South Korea, Norway, and Finland.
Research indicates the incubation period, the time where a deer carries CWD but doesn't show symptoms, can be as long as 24 months. It's common for an infected whitetail to live a normal lifestyle during that period, only showing signs of illness in the last few weeks of their life. Those photos of the emaciated deer and elk we've all seen show animals who've reached the clinical stage in development of CWD, and they're all within weeks of their death.
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We know this because CWD is fatal – every time. If a CWD positive whitetail deer does not die of another cause, it will, without question, die from the disease. It's because of this and a growing prevalence rate that the US officially declared a State of Emergency around the disease in 2001.
CWD is a form of TSE, or Transmissible Spongiform Encephalopathies. These prion diseases are rare disorders that develop holes in the brain, giving it a sponge-like appearance. Once infected, these bent protein prions can be transmitted through any orifice on an animal's body. Common forms of transmission are believed to be saliva, urine, mucus, and feces. Carcasses of infected animals are also a great host to prions, particularly the skull and spinal cord. One of the scariest facts on transmission is that these contaminated CWD prions can survive on water and on soil for months.
Other forms of TSE, like Creutzfeldt-Jakob Disease (CJD) and Mad Cow Disease (BSE) have been known to infect humans. Currently, there are zero known cases of CWD passing from an infected animal to a human. Much research is being done into whether or not this should be a concern and the long incubation period has some researchers concerned. Two Macaque monkeys, for example, contracted the disease at 5.4 and 6.2 years after eating meat from a CWD-positive deer.
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The Sky Is Falling There's a strong body of research that suggests CWD is a bigger concern than many believe. Over the past decade, deer population in western states has dropped significantly, some estimates say as high as 20 percent. This is not entirely due to CWD; however, the irony is hard to miss when considering the growing rates of CWD and the decreasing population.
In the heart of Wisconsin, hunters are experiencing this more than many others. In certain Wisconsin counties research suggests a coin toss could provide similar odds in determining whether the buck you harvested has CWD.
You're All Overreacting To some, the aforementioned data is inaccurate and completely misrepresents the impact of CWD. Some biologists argue the media and other scientists are to blame for the paranoia that surrounds the disease. In fact, video evidence can be found of at least one deer biologist eating meat from an infected deer simply because he isn't concerned about the impact. Interestingly, the CDC is following a case where a man unknowingly served venison from a CWD positive deer at a local wild game feed. 105 people were confirmed to have sampled the meat and the CDC is actively following each of them. None of them have yet shown any symptoms.
What about supplemental feeding? Many mineral and attractant companies would suggest the benefits for supplemental feeding outweigh the risks of having your deer population share saliva on a mineral lick or supplemental food source. Many states are banning the practice as a prevention tactic against the disease.
Recent studies suggest that CWD has been confirmed in a little over 6 percent of the counties in the US. One could argue then that its impact is relatively small and unworthy of the attention it's currently receiving. Those willing to dig into the data might also find that certain studies, like one done in Wisconsin, have mislabeled the cause of death for some deer, citing CWD, when in fact many of the animals were hit by vehicles and studied as roadkill. Advocates for this viewpoint argue that a deer is much more likely to die with CWD than from CWD, and that natural causes still play a more significant role.
The jury is still out. Regardless your stance on the position, we know a few things for certain. No one wants their local deer herd to come into contact with CWD, and we can all help reduce the spread by properly disposing of our harvested deer carcasses. And, now more than ever, we need to fund research and conservation efforts around this scary disease.
