Maggie Bonham is a long time hunter and game meat cook. She is also a writer on The LocaCarnivore, a website dedicated to local hunting.
Chronic Wasting Disease. If you've been hunting for any length of time, you've probably heard the term. You may have heard it's a disease similar to mad cow, but you've also heard that it may or may not affect humans. You may have also heard that it has decimated deer populations in many states. But you may not know is how it may impact hunting and why you need to be concerned when it comes to CWD.
What is CWD?
Chronic Wasting Disease or CWD is a form of transmissible spongiform encephalopathies (TSE) or prion disease. In layperson's terms, prion disease is caused by an abnormally folded protein. CWD is highly contagious to certain members of the deer family. Other prions similar to CWD include "Mad Cow" Disease (Bovine Spongiform Encephalopathy or BSE) in cattle, scrapie in sheep, and Creutzfeldt-Jakob Disease (CJD) in humans.
Unlike viruses and bacteria, prions are hard to detect, and even harder to eradicate. CWD affects deer, elk, moose, caribou, and Sitka deer. An animal that has contracted CWD may not have symptoms for years. When it does, CWD appears as severe neurological symptoms including drooling, widened stance, stumbling, and walking in circles. It's main symptom is the drastic loss of weight, hence the word "wasting." The animal looks sick and emaciated.
CWD is always fatal. There is no cure and no vaccine available.
How is CWD Transmitted?
Nobody knows for sure how CWD is transmitted, but scientists believe that animals transmit CWD through bodily fluids, such as urine, blood, saliva, and feces. CWD has been proven to live in the soil a long time. Animals that have died from CWD can infect other animals for years afterward. How many years is unknown, as it has been shown in one study that scrapie (a sheep disease similar to CWD) infected herds 16 years after a farm was left uninhabited and decontaminated. Scientists have proven that CWD can be transmitted through the soil, which is a definite concern. The prion binds to certain minerals in the soil, which keeps it active and infectious for a long time.
How Did CWD Come into Existence?
CWD is a fairly new disease. The first known case of CWD occurred at the Colorado Division of Wildlife Foothills Wildlife Research Facility on the Colorado State University campus in Fort Collins, Colorado in 1967. Captive mule deer died of a strange disease there and it was then that researchers made the discovery of CWD. It wasn't declared a prion disease until 1978.
Almost a year and a half after declaring CWD a prion disease, Wyoming Fish and Game Department’s Sybille wildlife research facility found CWD infected its captive herds of mule deer, blacktail deer, and elk.
The Colorado Division of Wildlife discovered the first case of CWD in a wild member of the deer family in 1981. The genie was out of the bottle, and there was no way to stuff it back in. CWD spread quickly among herds, and as of this writing 25 states, Norway, Finland, South Korea, and three Canadian provinces, have had positive cases of CWD in their cervids.
Some scientists speculate that CWD may be a mutation of the sheep prion disease, scrapie. Scrapie has been around since 1732--and may be much older. If CWD is a mutated form of scrapie, it may be a tough disease to get rid of, seeing as there is no treatment or vaccine for scrapie in sheep.
Can People Get CWD?
Currently, there is no proof that CWD can be passed to people. That being said, there is one study with macaques (a type of monkey that is closely related to humans) that showed macaques can contract CWD. A previous study with macaques had no infected animals. Scientists don't know why one study had infected monkeys and another did not.
However, even though humans are closely related to macaques, there has been no positive evidence suggesting that people do get CWD. Furthermore, there has been no increase of Creutzfeldt-Jakob Disease in people living and hunting in areas with CWD.
Even so, scientists don't know if it can be transmitted to humans. So, to avoid possible infection, they recommend not eating meat from a CWD positive animal. Experts recommend boning out the animal and not eating portions where the prion clusters, such as the brain, spinal column, pancreas, lymph nodes, and eyeballs. They recommend wearing gloves and washing thoroughly to avoid possible transmission.
Why Hunters Should Be Concerned
CWD is possibly the worst thing to happen to hunting, outside of the anti-hunting crowd. If CWD proves to be able to transmit to humans--something none of us want to think about--no sane hunter will want to hunt an area with CWD animals. We'll see hunting numbers decrease, simply because no one would seriously want to risk their lives by contracting the disease through the animals' meat, blood, and other bodily fluids.
If CWD does become a zoonotic disease, eating venison (deer, elk, caribou, and moose) is likely to disappear. It is a serious problem, and one that is unlikely to be remedied anytime soon.
CWD is a huge impact on the hunting industry as well as the states that have CWD within their cervid populations. One study shows that CWD kills off 19 percent of the Wyoming deer herd annually. The numbers are sobering, because without control or new animals, the entire Wyoming deer herd could disappear in 41 years. Now, consider that half the states in the US have CWD in their cervid populations. Without some type of control, hunters could see the end of big game hunting in their lifetimes. We will certainly be seeing a lot less deer and elk because of the disease, which will, in turn, limit or end our hunting opportunities.
What You Can Do to Prevent Transmission of CWD
Preventing CWD is hard, but there are plenty of ways you can help decrease CWD's spread.
- Sign up for game damage, CWD, and other hunts designed to reduce populations and break up mega-herds. The large herds are responsible for transmission of CWD--smaller herds are less susceptible and are less likely to come into contact and spread CWD.
- Do not transport animals, heads, or meat from CWD areas to areas that don't have CWD. Have your game processed in the CWD area and bring home wrapped meat and taxidermied animals.
- Report sick animals to your state's game management or division of wildlife.
- Do not shoot or take sick animals.
- Use disposable gloves to dress animals. Wash hands and any skin that has had contact with blood or fluids.
- Have your game animal tested for CWD, especially if your animal is in a CWD area. Often, these tests are free in CWD regions.
- Have your meat butchered (or butcher it yourself) into boneless cuts.
- Do not allow spinal fluid or brain matter to come in contact with your meat.
- Do not eat the brain, eyeballs, spine, bone marrow, tonsils, lymph nodes, or pancreas of your game meat. While most hunters wouldn't eat those nasty parts, some people might, so be sure you're not one of them.
- If your game comes back tested CWD positive, be sure to dispose of the meat.
- Don't just hunt the big trophy animals. Instead look at hunting animals that your state's game management experts want you to hunt to reduce CWD in herds.
A Piece of Good News
If there's a bright spot to any of this, it is the genetics of certain cervids. Researchers have identified certain genes that make some deer and elk more resistant to CWD than others. The problem is that those animals are often in the minority, which means CWD is more likely to get worse before it gets better. Whitetail deer seem to be more resistant to CWD than mule deer and elk, but even whitetails can succumb to the disease.
A new study indicates that elk populations are slowly adapting to CWD. Elk herds exposed to CWD have a rare protein and a different gene than those that have not been exposed. These elk live longer with the disease, breed, and produce offspring before succumbing to CWD. Perhaps this is the first step toward gaining immunity.
Hunters can help keep CWD at bay by participating in CWD and game damage management hunts designed to split up mega-herds that can become diseased quickly. Keeping herds smaller will reduce the spread of CWD and keep a healthier deer and elk population.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2018 MH Bonham