If you live in an urban area, should you be concerned about the spread of chronic wasting disease (CWD) in U.S. deer herds?
CWD has caused hundreds of captive deer to be euthanized on commercial deer farms in Michigan, Wisconsin, Illinois, Iowa and Pennsylvania. The disease has also spread to non-captive (wild) deer herds.
CWD hasn’t been widely publicized. So it’s no surprise that many people, whether they live in rural or urban areas, are unaware of the issue. But among those urban dwellers who are aware, there’s often little concern—because most people think CWD affects only rural areas, namely hunters and Departments of Natural Resources (DNRs) that depend on hunting licenses for revenue.
In fact, recent scientific reports suggest that whether you live in the city, the suburbs or the country, you should be concerned about CWD—and you should take precautions.
What is CWD?
CWD is a fatal, transmissible neurological disease that affects members of the deer family, including white-tailed deer, mule deer, elk and moose.
It’s called a “prion” disease because it’s caused by microscopic “prions,” defined by the National Institutes of Health (NIH) as “misfolded forms of proteins naturally found in the body . . . [that] can convert normally folded prion protein molecules into an infectious form when they come in contact with each other.”
According to the NIH, these misshapen prion proteins clump together and accumulate in brain tissue. Once that happens, it’s impossible to get rid of them. They aren’t deactivated by cooking, heat, autoclaves, ammonia, bleach, hydrogen peroxide, alcohol, phenol, lye, formaldehyde or radiation.
But here’s something that gets very little attention: Prions also remain in the soil indefinitely.
Colorado Division of Wildlife personnel recently found out just how indestructible prions are when they tried to eradicate CWD from a contaminated facility. Staff treated the soil with chlorine, removed the treated soil, then applied another chlorine treatment to the remaining soil and let the facility remain vacant for more than a year.
A year later, the soil still tested positive for the prion disease.
In humans, a prion-related disease is called Creutzfeldt-Jakob disease (CJD), a degenerative brain disease that leads to dementia and is ultimately fatal. CJD in humans is similar to bovine spongiform encephalopathy (BSE), more commonly known as mad cow disease.
Research suggests CWD not limited to animals and humans
CWD is commonly thought to affect only animals. However, a 2015 study by University of Texas Health Science Center suggests that the leaves and roots of grass plants can bind, uptake and transport infectious prions.
Even highly diluted amounts of the infected prion protein were absorbed by the roots and leaves of the grass plants, in as little as two minutes, according to the UT the researchers. When fed to hamsters, the prion-contaminated grass infected the hamsters.
The fact that humans could eat grass plants—such as wheat grass, typically considered a health food—infected with CWD should give people pause, regardless of where they live.
Here’s another reason for people who don’t live in rural areas to fear prion diseases like CWD: Researchers at the National Institute of Allergy and Infectious Diseases, the University of California at San Diego and UC-San Francisco, found that people with CJD have the prions in their eyes. That means there is a risk for the disease to spread via prion-contaminated instruments, during eye surgeries or even routine eye exams, according the researchers.
As reported by Live Science, researchers "found prions in all eight regions of the eye that were tested, including the cornea, lens, ocular fluid, retina, choroid (a part of the eye that contains blood vessels and connective tissue), sclera (the white of the eye), optic nerve (which connects the back of the eye to the brain) and extraocular muscle (which controls eye movement)."
Where do prion diseases come from?
Mad cow disease (Bovine Spongiform Encephalopathy (BSE), also transmitted by prions, is widely believed to stem from the cost-cutting practice of feeding cows to cows. Similarly, CWD may have man-made origins.
Captive deer operations are a main source of CWD due to their concentration of animals, “communicability window” (from trophy stock trading and escaped animals) and questionable feed sources. In a four-part expose, the Indiana Star revealed how “the pursuit of deer bred for enormous antlers and shot in hunting pens” on trophy farms is spreading CWD at an alarming rate.
Infected sheep may also be to blame. In the mid-1960s, the Department of Wildlife ran a series of nutritional studies on wild deer and elk at the Foothills Wildlife Research Facility in Fort Collins, Colorado. Soon after the studies began, however, Foothills deer and elk began dying from a mysterious disease.
It turns out that the deer may have developed CWD as a result of being held at the same facility with sheep that had had scrapie, a fatal, degenerative prion disease affecting the central nervous system of sheep and goats. Research shows that white-tail deer exposed to scrapie are susceptible to developing CWD.
Can you get Creutzfeldt-Jakob disease (CJD) by eating CWD-infected deer meat?
The official position of Departments of Natural Resources (DNR), which depend on revenue from deer-hunting licenses, is that humans can’t get CJD from eating venison from deer infected with CWD.
Yet a 2002 Centers for Disease Control study contradicts that claim. The study, "Fatal Degenerative Neurologic Illnesses in Men Who Participated in Wild Game Feasts,” found numerous cases of hunters and/or men who ate venison who had developed CJD.
To reduce their CWD risk, DNRs warn hunters to wear surgical gloves when cutting up deer and to avoid exposing open cuts or sores on their hands. They tell hunters not to eat a deer’s brain, eyeballs, spinal cord, spleen and lymph nodes. Yet, scientific articles say that muscle, blood, fat and other parts of the animal, including kidneys, pancreas, liver, saliva and antler velvet, also contain prions.
What can consumers do to avoid risk?
There are a number of ways you can limit your personal risk, and also help minimize the overall risk of the spread of CWD.
Take these three critical steps to avoid personal risk:
• Avoid eating venison, especially if it comes from “farmed” deer fed animal waste. Because it’s nearly impossible for deer processors to sterilize their equipment after each deer, cross-contamination is always a risk.
• Avoid any meat that comes from a factory farm. Factory farms often feed confined animals slaughterhouse waste, or rendered animal protein. This practice is prohibited in organic meat production.
• Make sure your eye doctor is aware of the new and concerning risks presented by patients who may have prion diseases.
Here are some things you can do to help address the overall problem:
• Call for an end to game farms. Deer breeding and “trophy farms” are a $4-billion/year industry. Farmers operate canned "hunts" in which bucks with trophy antlers can fetch six figures. Customers are guaranteed a kill, and the animals are sometimes drugged. Deer farm operators also sell antlers, velvet, urine and meat.
• Protest the widespread trapping and killing of wolves. Wolves serve the important ecological purpose of culling diseased deer from the herd––a function which is lost when they are hunted and trapped.
• Call on the CDC to require autopsies on people whose death certificate reads "Alzheimer’s disease" or "dementia." Many of these people, especially deer hunters, actually have died from CJD but are buried or cremated with no disclosure. The public deserves to know these risks, which can be transferred through surgical instruments and bodily fluids.
Martha Rosenberg a freelance journalist and frequent contributor to the Organic Consumers Association (OCA). Ronnie Cummins is OCA’s International Director. To keep up with OCA’s news and alerts, sign up here.