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Neurodegenerative Disease in Wild Deer Is on the Rise — What Eating Infected Meat Might Mean for Your Health

Chronic wasting disease1 (CWD) is a form of bovine spongiform encephalopathy (BSE), a lethal neurological disease. CWD is very similar to mad cow disease, another form of BSE, but whereas mad cow affects cattle, CWD affects deer, elk and moose. The human disease variant of mad cow is known as Creutzfeldt-Jakob.

BSE is caused by toxic and infectious proteins known as prions, not bacteria or viruses, as one might expect. Infected animals typically die within three years. As previously explained in Scientific American:2

“Prions are misshapen yet durable versions of proteins normally present in nerve cells that cause like proteins to misfold and clump together, starting a chain reaction that eventually consumes entire brain regions … [S]cientists have learned that such a process may be at work not only in mad cow and other exotic diseases but also in major neurodegenerative disorders….”

Indeed, in the past two decades, researchers have discovered a compelling link between a particular kind of protein known as TDP-43 — which behaves just like the toxic prions causing BSE — and human neurodegenerative diseases such as Alzheimer’s, Parkinson’s and Lou Gehrig’s disease.3

According to research4 published in 2011, TDP-43 pathology is detected in 25 to 50 percent of Alzheimer’s patients, particularly in those with hippocampal sclerosis, characterized by selective loss of neurons in the hippocampus, which is associated with memory loss. Other research shows Alzheimer’s patients with TDP-43 are 10 times more likely to have been cognitively impaired at death than those without it.5,6

CWD Is on the Rise

According to recent reports, CWD is now found in 16 percent of male animals tested in Colorado. One particularly hard-hit herd of deer in Boulder, Colorado, was found to have an infection rate of 40 percent. As noted by The Denver Post,7 Colorado Parks and Wildlife leaders recently announced that combating CWD is a top priority. To that end, a special task force has been launched to develop strategies aimed at tracking the disease.

A key component is to require hunters to test their kills for presence of CWD, and to reduce prevalence by encouraging hunters to hunt bucks in herds known to have high infection rates. (It should be noted that infected animals should NOT be eaten, due to the potential risk of transmission of the infection.) Mike Miller, a Colorado Parks and Wildlife veterinarian, describes the telltale signs of infection in animals as follows:8

“As the central nervous system damage progresses, behavioral signs become more apparent. The animals aren’t paying attention. They may not respond. They may lag behind. As things progress more, they have more trouble moving. They carry their head differently. They don’t pick their feet up the way they should.

In the later stages, some animals pick up a habit of drinking lots of water. Some develop a difficulty swallowing. They tend to feed inefficiently. They’re sort of mouthing the plants but not biting and swallowing the way a normal animal would.”

Hunters Urged to Test All Carcasses and Share Results

Other proposed strategies to contain the disease include “Discouraging large gatherings of deer, elk and moose to slow the spread of CWD via exchanges of animal body fluids. Tactics include removing of salt licks … and enforcement of rules prohibiting baiting of big game.” They will also tighten requirements for safe disposal of infected carcasses at landfills and prohibit the transport of carcasses between states. Matt Dunfee, director of the Chronic Wasting Disease Alliance issued the following statement:9

“If you are a hunter, we will need you to hunt because we need the samples you can provide. If you are a wildlife enthusiast and want to see healthy deer and elk, you’ll need to push for funding for studies and for implementing all the recommendations in this plan for scientific management of CWD.

The challenge for the public will be allowing these animals to be harvested. This disease does not go away. There is no vaccine. It is always fatal. And the only hope we have to manage it is to try to keep the prevalence low.”

Importantly, hunters are urged to test all meat before consuming it. The idea that a healthy-looking animal is going to be free of the disease is a foolhardy approach at best. “The vast majority of the time hunters find out their animal has CWD, they’re shocked, because it looked great. It was moving just like everything else. It had great body fat,” Dunfee says.10

The reason for this is because the disease develops over time. An animal may remain asymptomatic for up to two years. And, while some insist there’s a strong species barrier between deer and humans, research linking the prion-like protein TDP-43 to neurological diseases in humans hint at a potential risk of eating contaminated venison.

How Modern Farming Methods Created Mad Cow Disease and CWD

Store-bought meat from animals raised in concentrated animal feeding operations (CAFOs) are not necessarily a safe bet either. Mad cow disease is a result of forcing natural herbivores to eat animal parts and byproducts, and from my perspective, the possibility of contracting a lethal neurodegenerative disease is just one more in a long list of reasons to avoid CAFO meats. As mentioned earlier, the protein TDP-43, found in many with Alzheimer’s, acts like the toxic and infectious prions11 causing mad cow and CWD.

Mad cow disease and CWD are both essentially man-made diseases, created through modern factory farming methods in which herbivores are forced into cannibalism. One of the primary modes of transmission of mad cow is feeding cows bone meal and waste products from other cattle infected with the disease.

As a result, it’s now illegal to feed beef-based products to cows. However, the beef industry still uses chicken litter in cattle feed — a mixture of chicken manure, dead chickens, feathers and spilled chicken feed, the latter of which includes cow meat and bovine bone meal — and that too can introduce mad cow disease.

Pigs, chickens and turkeys can also be fed cattle byproducts, and current laws permit byproducts of those animals to be fed back to cattle12 as well. This is a second loophole that can allow mad cow agents to infect healthy cattle — and you, should you end up eating infected meat. Similarly, CWD is the result of domesticating wild animals and feeding them an unnatural diet. The disease is often imported and spread via game farm animals.

Infected deer and elk shed the infectious prions in saliva and urine, starting around three months after being infected. They remain contagious for the remainder of their life, contaminating land and water as they go along. Game farms cater to hunters who are more or less guaranteed a kill, and the potential for these infectious prions to spread to humans through consumption of infected game animals is therefore a valid concern.13

Eating BSE-Infected Meat Can Be Deadly

Eating beef infected with mad cow — which, again, is very similar to CWD — is known to cause Creutzfeld-Jakob disease in humans. Symptoms are similar to Alzheimer’s and include staggering, memory loss, impaired vision, dementia and, ultimately, death.14 Between 2002 and 2015, prevalence of Creutzfeld-Jakob rose by 85 percent across the U.S. In 2015, there were 481 cases.15

There’s no effective treatment, and death typically occurs within a year. As noted by Center for Food Safety, which reported on a 2012 mad cow outbreak:16

“Tissue from infected cows’ central nervous systems (including brain or spinal cord) is the most infectious part of a cow. Such tissue may be found in hot dogs, taco fillings, bologna and other products containing gelatin, and ground or chopped meat. People who eat contaminated beef products are at risk of contracting the human version of mad cow disease…

The disease slowly eats holes in the brain over a matter of years, turning it sponge-like, and invariably results in death … The incubation period for mad cow disease in cattle is thought to be approximately five years; it may be latent in humans for a decade or more before manifesting itself.”

The prions causing CWD may also mutate over time, thereby facilitating interspecies spread. As noted by Dunfee, “A strain could be steps from vaulting the species barrier between deer and people.” So, if you’re a hunter, please make sure to test the meat for CWD, and if found positive, don’t eat it, and follow reporting and safe disposal protocols.

The Case for Foodborne Alzheimer’s

The idea that neurodegenerative diseases like Alzheimer’s and Lou Gehrig’s may be spread via CAFO meats goes back at least a decade. A 2005 study17 published in the journal Medical Hypotheses, titled “Thinking the Unthinkable: Alzheimer’s, Creutzfeldt-Jakob and mad cow disease, the Age-Related Reemergence of Virulent, Foodborne, Bovine Tuberculosis or Losing Your Mind for the Sake of a Shake or Burger,” states:

“In the opinion of experts, ample justification exists for considering a similar pathogenesis for Alzheimer’s, Creutzfeldt-Jakob and the other spongiform encephalopathies such as mad cow disease. In fact, Creutzfeldt-Jakob and Alzheimer’s often coexist and at this point are thought to differ merely by time-dependent physical changes. A recent study links up to 13 percent of all ‘Alzheimer’s’ victims as really having Creutzfeldt-Jakob disease.”

The researchers also note that bovine tuberculosis serves as a vector for mad cow disease in humans, which further increases the risks. Bovine tuberculosis is one of the most prevalent disease threats in American CAFOs, and the researchers quote data from the U.S. Department of Agriculture suggesting that anywhere from 20 to 40 percent of American dairy herds are infected at any given time. According to the authors:

“The health risk for milk tainted with M. bovis has been known for decades and there was a time not so long ago when ‘tuberculin-tested’ was printed on every milk container. Schliesser stated that meat from tuberculous animals may also constitute a significant risk of infection. At the turn of the 20th century 25 percent of the many U.S. deaths from TB in adults were caused by M. bovis.

Dairy products aside, when past and present meat consumption are factored in, there is three times the risk of developing Alzheimer’s in meat eaters as opposed to vegetarians.

The investigation into the causal trail for Creutzfeldt-Jakob, indistinguishable from Alzheimer’s except for its shorter, lethal course might have grown cold where it not for Roel’s and others who linked mad cow in cattle with M. bovis and related paratuberculosis on clinical, pathologic and epidemiological grounds.

The southwest of the U.K., the very cradle of British BSE and CJD [Creutzfeld-Jakob disease] outbreaks, saw an exponential increase in bovine tuberculosis just prior to its spongiform outbreaks. All of this brings up the unthinkable: that Alzheimer’s, Cruetzfeldt-Jackob, and mad cow disease might just be caused by eating the meat or dairy in consumer products or feed.”

Take Control of Your Health by Choosing Your Foods Wisely

Could Alzheimer’s disease, which now is the third leading cause of death in the U.S., be the result of a slower-acting form of mad cow or CWD? As shocking as that may sound, the links between the diseases are compelling, and they all point to one main culprit: factory farm practices, which eliminate hygiene and replace animals’ natural diets with unnatural grain diets, into which animal byproducts are mixed in.

This sets in motion a disease-producing cycle that can only be stopped by reverting back to farming according to natures design. The bottom line is, an animal’s diet matters greatly. You cannot judge the benefits of the animal’s diet based on added weight gain or added milk production alone. There can be all sorts of unforeseen ramifications when you alter the natural course of nature, including man-made scourges like mad cow and CWD.

Organic, grass fed and finished meat that is humanely raised and butchered is really about the only type of meat that is healthy to eat. The American Grassfed Association currently certifies producers of 100 percent grass fed beef and animal products, so be sure to look for “AGA Certified” when shopping for grass fed beef. If you live in the U.S., the following organizations can help you locate farm-fresh foods raised in a humane, sustainable manner:

Demeter USA provides a directory of certified Biodynamic farms and brands. This directory can also be found on

American Grassfed Association

The goal of the American Grassfed Association is to promote the grass fed industry through government relations, research, concept marketing and public education.

Their website also allows you to search for AGA approved producers certified according to strict standards that include being raised on a diet of 100 percent forage; raised on pasture and never confined to a feedlot; never treated with antibiotics or hormones; born and raised on American family farms. provides lists of farmers known to produce raw dairy products as well as grass fed beef and other farm-fresh produce (although not all are certified organic). Here you can also find information about local farmers markets, as well as local stores and restaurants that sell grass fed products.

Weston A. Price Foundation

Weston A. Price has local chapters in most states, and many of them are connected with buying clubs in which you can easily purchase organic foods, including grass fed raw dairy products like milk and butter.

Grassfed Exchange

The Grassfed Exchange has a listing of producers selling organic and grass fed meats across the U.S.

Local Harvest

This website will help you find farmers markets, family farms and other sources of sustainably grown food in your area where you can buy produce, grass fed meats and many other goodies.

Eat Well Guide: Wholesome Food from Healthy Animals

The Eat Well Guide is a free online directory of sustainably raised meat, poultry, dairy and eggs from farms, stores, restaurants, inns, hotels and online outlets in the United States and Canada.

Community Involved in Sustaining Agriculture (CISA)

CISA is dedicated to sustaining agriculture and promoting the products of small farms.

The Cornucopia Institute

The Cornucopia Institute maintains web-based tools rating all certified organic brands of eggs, dairy products and other commodities, based on their ethical sourcing and authentic farming practices separating CAFO “organic” production from authentic organic practices.

If you’re still unsure of where to find raw milk from organic, grass fed cows, check out and They can tell you what the status is for legality in your state, and provide a listing of raw dairy farms in your area. The Farm to Consumer Legal Defense Fund18 also provides a state-by-state review of raw milk laws.19 California residents can also find raw milk retailers using the store locator available at

About Dr. Joseph Mercola (67 Articles)
Dr. Mercola finished his family practice residency in 1985 but was trained by the conventional model. In his first years of private practice, he treated many symptoms with prescription drugs and was actually a paid speaker for the drug companies. But as he began to experience the failures of this model in his practice, he embraced natural medicine and has had an opportunity over the last thirty years to apply these time tested approaches successfully with thousands of patients in his clinic. Over 15 years ago he founded to share his experiences with others. The site is the most visited natural health site in the world for the last seven years with nearly two million subscribers. He's also written two NY Times bestselling books, and has had frequent appearances on national media including the Dr. Oz show and major news channels.
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