The Reality of Chronic Wasting Disease

In Southwest Montana, as the winter snow melts revealing a grotesque aftermath, a crew of men drive through their ag fields towing a flatbed trailer, scanning the ground for the remains of whitetail deer. They pull alongside, throw a wasted carcass onto the trailer, and drive to the next. This year they’ve loaded over 80 dead animals and hauled them to a massive 10-yard dumpster, the kind you would see at a construction site, and sent them to a dump. They filled the first dumpster and ordered another.

Collecting the remains of deer to get them off the fields and into landfills has become a weekly occurrence for ranchers in SW Montana.

Our limited understanding of the history of Chronic Wasting Disease (CWD) only goes back to the 1960’s in Colorado where a captive deer at a research facility became the first animal where the disease was detected. Read that sentence again. The spread moved slowly North into Wyoming and was again found in a captive animal. The earliest study about whether CWD could transfer to humans was published in 2004, at that time it was only known to be found in deer and elk. It should be noted that whitetail deer were extirpated from SW Montana where these photos were taken in the 1890’s in a single year from what was described then as “black tongue.” Replacement deer were brought there in a trailer after WWII from Ovando, MT to create an additional source of meat for area residents. As is often the case with introduced species, they rapidly exploited the habitat and expanded their population rapidly.

Coyotes and birds are quick to consume these deer, spreading the disease through their feces wherever they go afterward.

Today, CWD has been detected in 27 states, Canada, Norway, Sweden, Finland, and South Korea in deer, elk, reindeer, sika deer, and moose— all animals within the family Cervidae. Recent experimental transmission studies indicate caribou are also susceptible to the disease. (Kuznetsova, Alsu, et al. “Potential role of soil properties in the spread of CWD in western Canada.” Prion 8.1 (2014): 92-99.) It is not known whether CWD can be transferred to humans, but within laboratory settings it has been transferred to mice with human genes, squirrel monkeys, and the Macaque, a primate that bears incredible genetic similarities to humans. Perhaps most alarming, is that the transfer of CWD to this primate was done by feeding it the meat of a Cervid who was infected with CWD but wasn’t showing any symptoms. A similar study was conducted in 2018 which did not show the Maceque as able to contract CWD.

CWD is a prion disease. A prion is a mutated protein, which has no nucleic acid, meaning that it cannot be killed like bacteria and viruses which cannot tolerate UV, heat, bleach, etc. Animals can become infected by drinking contaminated water, eating contaminated food, nose-to-nose contact, through bodily fluid transfer, or from eating an infected animal. Say one of these CWD deer in Montana dies in a hayfield, and those prions go into the soil and come back up in the hay, and that hay gets sold and transferred somewhere else… that’s where these prions go as well. There is no science to back this theory up, I’m just grasping at potential ways to understand how CWD can jump large distances and show up in new areas. A lot of what we understand about prions is so limited that the word “hypothetical” gets thrown over any statement like a wet blanket. We don’t currently have the means of testing plants to see if they contain the prion which causes CWD.

A suspected infected whitetail doe. An animal whose body condition appears poor is an early sign of CWD. There is no test available for live animals, yet scientists continue to proclaim the disease is 100% fatal.

Once this prion is inside an animal it travels to the brain. As it contacts other proteins, it causes them to mutate and become prions and spreads from the nervous system to the lymphatic system and then into every other part of the animal. Other prion diseases are Scrapie (found mostly in sheep), Mad Cow disease (which did infect and kill humans), and Creutzfeldt-Jakob disease. 

According to the CDC, prion diseases are always fatal. Brandon Mason from Eastman’s Hunting Journal brought up a very interesting point on that subject— how can we know CWD is 100% fatal if we cannot test live animals? That’s a problem.

Back on the ranch in Montana the manager first noticed extra “winterkill” in 2012, where there’d be around 20 dead animals in the field each spring, that number started to tick up in 2015, and by 2020 they were starting to observe living deer that looked very sick. The first case of CWD confirmed in Montana was near Billings in 2017 near the Wyoming border. On the ranch, they tested their first deer for CWD in 2019 and it came back as infected. In 2020, they tested every single deer they harvested with 30.9% of those tested coming back as positive. In 2021, they again tested every single animal they harvested and 60.1% came back as positive, substantially higher than the maximum 50% that has been described in peer-reviewed literature. This particular ranch is an excellent whitetail deer habitat, and the population has been well monitored. Since 2002 the density of whitetail was 130 deer per square mile. The survey this spring has that number reduced to 50 deer per square mile. It is likely that the density of deer in this area created a situation where the disease could spread quickly. In 2015 they harvested 38 deer per square mile which comprised of 21% bucks, this harvest rate did not increase or decrease the 130 deer per sq mile population. Since the increase of CWD, biologists have taken a similar approach to what they did with the Bighorn Sheep of the Tendoy Mountain Range, also in SW Montana, which is to eradicate the population. Easier done with sheep than deer.

A mature buck’s remains, at an age where he should be at his physical prime.

The likelihood is that every deer on this Montana ranch has been exposed to CWD but not all of them have died, which makes a guy wonder about the whole 100% fatal thing. We need to be taking a hard look at the deer which are exposed and not dying because therein may lie the answer to how to beat this problem.

Each deer harvested on this ranch gets weighed with its guts in as a “live weight” before being processed in an indoor facility. A hanging weight, the sex, the antler score on bucks, and whether a doe has milk or not is also recorded. Two teeth are pulled from each animal and sent to a lab to determine the animal’s age. This data has become helpful in the early detection of CWD. The average weight for a 5-year-old buck varies between 194 and 224lbs, largely depending on the amount of precipitation the land gets in a given year. A positive CWD buck killed in 2021 weighed 154lbs.

As the prions spread through the animal, their muscle mass decreases, holes and lesions develop in their brain, they stagger and salivate, and become irrational. They also lose their fear of vehicles, humans, and predators. Some develop pneumonia and drown. The early phases of this breakdown make them much easier to hunt, which increases the chances a hunter unknowingly takes home infected meat. Infected animals become excessively thirsty and urinate more, spreading the disease farther. Their ears become droopy, and bucks become less likely to shed velvet. “CWD can affect animals of all ages and some infected animals may die without ever developing the disease. CWD is fatal to animals and there are no treatments or vaccines.” CDC website. Domestic livestock have not been naturally infected yet, but by injecting the prion into their brains, goats, sheep and cattle have all become infected in a lab setting. (Williams, E. S. “Chronic wasting disease.” Veterinary pathology 42.5 (2005): 530-549.)

The test for CWD in Montana starts by removing a gland behind the deer’s jaw, it’s the same gland that swells up in your neck when you are sick. The testing process takes 52 steps to confirm and costs $17. Results take as long as three weeks. Of course, most folks don’t have cold storage to hang an animal for that long, and if the results come back as infected, they have now contaminated their facility. This puts hunters in quite a pickle. The CDC also recommends not using a knife to process a potentially infected game animal that you would use for any other purpose. It is not known at which stage of infection results become conclusive, but animals as young as 17 months have died from CWD.

As of January 2022, these are the counties where CWD has been confirmed. There is no scientific consensus about how CWD has been able to spread to isolated areas. Increased testing will likely increase the area where infected animals reside.

What do we have to lose? Quite a bit. This has the potential to continue spreading through carrier species and continue to affect individuals and populations in new areas. As lab studies have indicated, species like primates can be affected. In case you were duck hunting on that day of school, humans are primates. We could see dramatic decreases of our Cervid populations. Without the money from deer and elk hunting, every state wildlife agency in the country will likely go bankrupt. Areas like SW Montana, which depend on outfitting for much of their revenue are being devastated financially. Over 25 million dollars were spent on outfitters in Madison County alone in 2021. Property values are going down, and people are afraid to eat the venison their families have depended upon for generations.

What can we do? For starters, we need to test our animals. CWD isn’t found everywhere, but it also isn’t tested everywhere. Talk to your local biologist and see what they need in order to test the deer or elk you shoot. We need to stop moving meat around the country, especially from known CWD areas. We need to throw our weight into learning about prions, how they move through systems, and which proteins they mutate and are mutated from. We need to find a way to test living animals and a faster means of testing dead ones. A field testing kit would be ideal. Mostly, we need to take CWD seriously and do our best to stop the spread without making hasty decisions.

I’d like to thank the owner and manager of the SW Montana ranch for providing their data and photos for this article. The quorum of data used to understand this disease in the region has come from them, and without their contribution to science, we would be farther from understanding this disease than we are now. I offer my condolences to them for the loss of wildlife they have worked so hard to manage for. They asked not to be recognized.

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About the author: James Nash is an outfitter, professional hunter and cattle rancher from NE Oregon where he resides as the fifth generation of his family to raise cattle, hunt, and fish on the 6 Ranch. He studied history at Adolf Øien Videregående in Trondheim, Norway where he also competed on the Norwegian National Greco-Roman wrestling team, then studied Literature and Writing at the University of Montana Western in Dillon, Montana. Afterwards, Nash served as an Armor Officer and platoon commander in the M1A1 Abrams main battle tank in the US Marine Corps for five years. Nash was wounded in Afghanistan and received two Purple Heart Medals and after a period of convalescence was subsequently retired. He returned to the 6 Ranch and resumed guiding and outfitting, with a focus on other combat wounded veterans. Nash has guided salt and freshwater fly and gear fishing, all kinds of hunting, and back country wilderness trips since age 14. He hosts the 6 Ranch Podcast, and you can learn more about him on instagram @6ranchoutfitters.

{ 8 comments… add one }
  • Mike Bias April 7, 2022, 12:09 am

    Ben Gorman, you would do well to read something besides social media posts from you favorite outdoor bloggers. The author clearly points out these cross-species jumps were described from laboratory settings published within peer-reviewed scientific journals. The author appears to have done a comprehensive and timely search of the available published literature. EHD (epizootic hemorrhagic disease), though rampant in Montana last year, was primarily across the high-line of northeastern Montana along the Milk River and Missouri from Glasgow to North Dakota. Although, it was also detected along areas of the lower Yellowstone River. EHD also affects deer rapidly within a season, the infected animals usually dying quickly, and substantially easier to diagnose than CWD. Further, EHD often shows recurrence in the same areas across years. CWD on the other hand often takes months or years to manifest in an individual, has no cure, and can only be confirmed from complex analysis of dead animal tissues. Nothing in this article was sensationalized. The author has some very salient points that we, as wildlife managers, hunters, and conservationists need to take very seriously. Please, take some time, get to a University library, and read a book or two on wildlife disease or a journal before shooting your mouth off on something you clearly know little about.

  • Kyle Nye April 5, 2022, 1:52 pm

    Good article. Lots of good info in there. Glad to see some light being shed on a topic that needs more attention by the hunting community.

  • Ben Gorman April 5, 2022, 9:25 am

    So many false things in this report it’s not even funny. The epidemic that killed off thousands of whitetail deer this past year was caused by EHD dude, you don’t even have the right disease. And to report that CWD has now made the jump to cattle and primates is completely false and irresponsible. The impact of false reporting like this is astronomical and this article should be taken down.

    • Beau Ohm April 5, 2022, 10:20 am

      Ben, do you have any peer reviewed articles or studies to rebut what this article has stated? Would be interested in articulate response rather than defaming the writer.

    • Big Al 45 April 5, 2022, 10:35 am

      That’s one hell of a claim Ben.
      So, who are you, and what are your credentials?
      In addition, what are and where are your citations for your claims?????
      You owe it to everyone here and society in general to cite sources for your claim, otherwise YOU are doing what you accuse others of doing.
      Cowboy up Ben.

    • James T Nash April 5, 2022, 10:56 am

      Feel free to check out the peer reviewed scientific literature I cited on these points and provide any of the same that contradicts them.

      • JEFF April 12, 2022, 7:12 pm

        I agree with the people calling out Ben, but I am a bit confused by some of your comments, and concerned by another. First, let’s address the bleach isn’t effective thing. Bleach does indeed work to inactivated prions and clean surfaces, chunks of meat etc. need to be removed prior to cleaning.

        Maybe things are different in your area, but I would say there is no shortage of people trying to solve all of the issues you bring up, Universities are studying all aspects of CWD. Prions in general aren’t something new to the world of science, and are constantly being studied in people and animals alike. At the moment some of your (and my) hopes or wishes for CWD answers is a lot like bitching about a cure for cancer. I also don’t quite understand how you arrive at a conclusion live testing has not been figured out. (And some of your citations are 8 years old or older) Is it perfect? Probably not. But the facts are scientists have indeed found several ways of detecting CWD in live animals. I’m unsure how you are not aware of this as it was in just about every newspaper as a story out of Billings, Montana last year. The problem with live testing is it works great for farm raised animals, wild animals aren’t too likely to line up for testing. Proving a live animal has CWD doesn’t prove it isn’t always fatal anyway, so that argument seems a bit odd to me. On the plus side, people like you who get the word out about CWD to readers and fans helps make sure more people know about it. On the other hand, you missed the mark on some things, and that can be dangerous. I do however appreciate your articles.
        Best Regards,

    • JEFF April 13, 2022, 12:44 am

      There is always room for disagreement and discussion, and truly it should be encouraged. But your reply isn’t that. It is a poorly researched blatant, and might I add, nasty attack, for no reason. I’ll leave it up to others to slap you with some insults, but did you truly think *we would be impressed by anything less than facts or supported opinion? James was trying to spread knowledge about a subject that truly could disrupt not only big game in the wild, but everything from game farms, conservation and hunting Unfortunately our food chain supply could easily be affected should CWD jump species to bovine (that is a cow to you). So think of your audience before applying 3:00 a.m. social media skills to a real mans passion project.before you speak.

      *by we I mean people who have a true stake in this – otherwise known as hunters, game farmers, consumers and the like.
      Best of Luck to you big Ben…

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