THIS IS SCARY STUFF 

So it’s not a zombie disease, but it is just as scary. Chronic Wasting Disease (CWD) is a relatively newly identified member of the family of diseases known as Transmissible Spongiform Encephalopathies (TSEs). The way this group of diseases kills you is spelled out in its name. It is transmissible (duhhhh), affects the brain (encephalopathy), and the fun part…it kills cells in the infected individual leaving holes in the brain that make it resemble a sponge in appearance #NOTGOOD… TSEs affect a wide number of mammal species, including humans. Do you remember mad cow disease? That was a TSE. Have you ever heard of Creutzfeldt Jakob Disease (CJD)? Also a TSE. The route in which CJD and mad cow disease spread, helps spotlight the truly frightening aspects of CWD. So let me give you a brief history of each (this is fun!). 

WHERE DID IT COME FROM

All mammals have prion proteins in their body, mostly in the central nervous system. Scientists are not sure of the function of these healthy prions, but in very rare instances one of these proteins will misfold, causing other proteins in contact with it to do the same. This is known as the sporadic form of the disease. For CJD, an extremely rare TSE, this is usually where it ends. Prion diseases are always fatal with no cure, so the infected individual dies and the infected tissue in the brain remains there and is buried with the host. So how do we know it is transmissible? Well…this is a little gross…

      THE HUMAN VERSION

In Papua New Guinea an indigenous tribe had the cultural tradition of cannibalism as part of its death ritual. When a member of the group would die, their family and friends would consume the brain of the deceased to help them pass on into the afterlife safely (I think). At some point one member of the tribe sporadically acquired CJD, and you can guess what happened next. By consuming the brain of the deceased, tribal members became infected by the misfolding prions. There is also no effective treatment available for prion diseases, and in the case of transmissible CJD, within a year the infected individual is dead. You can see how this would cause a problem for the tribe in Papua, New Guinea. As more members of the community died, there were more funerals, and yes, more brains were eaten. Once the medical community investigated this phenomena, however, it was easy to stop. The cannibalism stopped, so the disease spread stopped. Unfortunately, to this day 1 million individuals worldwide die from the sporadic form of CDJ. But we don’t have to worry about it being transmitted to others. Now mad cow. 

MAD COW DISEASE

Mad cow disease or bovine spongiform encephalopathy (BSE), sporadically appeared in a cow in the United Kingdom in the 1980s. Unfortunately, this occurred during a time that the beef industry was looking to save money by using the left over parts of a cow (sustainably) as food for the alive cows. You heard correctly, the cows were participating in a cannibalistic ritual similar to the tribe in Papua New Guinea (without consent). By eating the tissue of the infected cow, others acquired the infectious prion protein, and the transmission cycle began. What makes this disease particularly relevant to our concern over CWD, is that a strain of mad cow disease broke the species barrier and began infecting humans. 232 people have died from mad cow disease, all living in or having traveled to the United Kingdom. Once authorities stopped the practice of intentionally forcing cows into cannibalism, mad cow has (hopefully) stopped transmitting to humans. Phew! That was a close one…but wait…I will now introduce you to CWD. 

WHY CWD IS WORSE…WAY WORSE

Chronic Wasting Disease is a TSE on steroids. First identified in Colorado in the 1960s, it is now found in deer populations in 26 states and 3 Canadian provinces, as well as Norway, Sweden, Finland and South Korea. Unlike the previous examples of prion diseases, where tissue from the central nervous system had to be ingested for the disease to spread, CWD can spread through bodily fluids such as saliva, urine, and fecal matter. Once these prions are leaked into the environment they remain contagious for years and possibly decades (yes you heard me correctly, decades). They can bind to certain soils and plants and can not be killed by strategies that work on viruses and bacteria (like extreme heat and ultraviolet light). So theoretically a deer could take a piss on some kale at an organic farm in California, and then end up in your vegetable section at whole foods in Vermont. From here you could take it home and cook it (cooking won’t kill the prions), put the sautéed Kale outside for a deer (I don’t know why), and the poor fuck could get CWD. Great! 
But there is more sports fans. For reasons scientists currently don’t understand, even though a prion is not a living organism (even by bacteria standards), it evolves. Or at least changes. New strains of CWD have been found. As the strains change, and more humans eat contaminated meat (yes, people are most certainly eating plenty of infected meat in states that have CWD), the likelihood of it jumping to humans increases. It’s analogies to continuing to put the ball on the roulette wheel and waiting for it to land on 7. In fact Dr. Osterholm, one of the primary investigators of mad cow disease, and now infamous for his joe rogan podcast episode in March of 2020, where he basically predicted exactly how Covid would spread throughout the world, has stated that it is inevitable that CWD will jump the species barrier to humans. YIKES! The one question I have is that if this happens, will it transmit between people like it does between deer? If that is the case, what would we do with infected people? Leprosy islands? Because every place where they spit, urinate, or defecate would be contagious for decades…So you wouldn’t want them going to the bathroom at your local Walmart. Anyways, long story short, wolves kill the sick and weak individuals in deer and elk populations, even before they are visibly sick (more coming on this soon). This is really important for stopping the spread of CWD among wild deer populations, by drastically shortening the time infected deer can shed the prions into the environment and between animals. In fact, if wolves still occupied their historic range it is possible CWD wouldn’t have entrenched itself in wild deer populations. So maybe we need a lot more wolves in a lot more places. What do you think?

Protecting Wolves and Bears (with Kristin Combs)