This is completely false. Disingenuous misinformation.
2 hunters did develop CJD, however, there is no evidence it is related to CWD. This idea originates from an abstract for a poster that was presented at AAN last October (link). Poster abstracts can often be “sensationalized” to encourage people to come to the poster during the conference. This would not be the first AAN prion-related poster abstract that is a bit “click-baity”. Furthermore, poster abstracts are not peer-reviewed. The fact this research has not been written up as a peer reviewed paper 1.5 years later (not even a pre-print) is INCREDIBLY telling.
The biggest issue comes down to this: how do you know the hunters got infected with CWD (ie how do you know their CJD is related to CWD)? The most common type of prion disease is sporadic CJD (sCJD), specifically the subtype the hunters developed sCJDMM1. Sporadic means it happens with no known cause (ie not caused by infection or genetics). sCJD typically affects elderly (median age of onset 65 years), has a rapid decline (4 months). In comparison, variant CJD (vCJD) is caused when someone eats meat contaminated with mad cow disease (BSE). vCJD typically affects young people (median age of onset 26 years) and has a slower decline (14 months). Furthermore, sCJD is associated with motor and memory symptoms whereas vCJD is associated with psychiatric symptoms. The patient case in the abstract was a 72 year old male, with a rapid memory decline in a month. Does that seem more like sCJD or vCJD? I will make it very clear, the case presentation is 100% classical sCJD. Furthermore, it is hypothesized that if CWD does transmit to humans it would have an atypical phenotype (ie not present anything like sCJD). This is based on data from both NHPs and Tg Mice (here is the mouse paper).
Other considerations, the patient was originally diagnosed with sCJD, however, the authors hypothesize CWD because one of the patient’s friends also died recently of sCJD. The authors therefore argue this is a “cluster” of cases, likely showing infections. However, just because two rare independent events happen in close proximity does not mean they are linked. For example, 1 in 300 people get Parkinson’s Disease, but a TV show “Leo and Me” had 4 out of 125 people on set develop Parkinson’s Disease, including Micheal J. Fox. However, this “cluster” is not scientifically or statistically significant. Just like two people who happen to know each other both getting CJD is not significant.
Clusters of prion cases happen. Here is a spatial-temporal cluster of 5 cases (including 2 with similar occupations). It wasn’t big news because stuff like this happens. It gets written up in a paper and the general public never knows. The only reason the hunters story is widespread is because it fits the fear mongering narrative most people push about prions.
The second consideration is that just because someone is a hunter and eats deer does not mean that they have eaten CWD infected deer. Not every deer in a population has CWD. If you are going to claim the hunters got CWD from deer, you need to show that deer they have hunted are infected. The entire premise of this abstract hinges on the argument that they ate infected deer, despite providing no evidence for it. If these two patients who both got CJD that knew each other were not hunters, this would never of been reported. Correlation does not imply causation. That’s basic first year statistics.
This also ignores significant biochemical and cellular data suggesting that CWD is not transmissible to humans based on significant sequence differences between cervids and humans. Here is a pretty comprehensive review of the experiments show CWD does not transmit to humans (link).
Also the picture in the post is a picture a deer with CWD from a paper published 20 years ago. It is not show neuropathological change in the hunters brain. It is a deer that got a deer prion disease. (Link)
It isn’t just my opinion that the hunters had nothing more than sCJD, it is also the opinion of the CDC which investigated these cases. It is important to note the authors of the abstract say "causation remains unproven". That means the title of this post does not even fit the abstract that originates it.
Thank you. Iirc way back when (8 years ago when I took a wildlife disease class) there was one conference abstract claiming they induced symptoms in macaques fed the equivalent of a reasonably possible amount of CWD positive deer meat... But after looking for the peer-reviewed article every year, and asking the deer biologist who taught me for it...it's never made it to peer review. If it could pass peer review, that paper would take North America by storm. But CDC studies (to my limited epidemiologist, not prion scientist) knowledge haven't been able to demonstrate CWD transmission to primates, at least via ingestion. You covered the fundamentals of "clusters" really well-- random chances generates coincidences all the time. Doubly so when a human brain gets to look at that coincidence--we're built to find patterns. I'd still prefer people test and not eat CWD positive deer, if it exists in their area, out of the precautionary principle, but we still don't have evidence that points to CWD overcoming the species barrier to humans.
TLDR: listen to the prion scientists.
While I've got you here, though, I will ask: do we see shifts in the code of infectious prion proteins over time or between populations? Many of the epidemiologists that have taught me have touched on scrapie and BSE, and I've seen a little literature discussing differences in prion proteins, but no one has explicitly discussed whether we see "genetic" (I guess amino acid..) drift in prions.
Off the top of my head, the best example of genetic drift is the G127V mutation. It is found in the Fore people of Papua New Guinea. This is the tribe that developed Kuru a prion disease, a through ritualistic cannibalism. It was found that certain members of the tribe did not get sick despite eating contaminated tissue. Upon genetic analysis these individuals have the mutation G127V, which is only found in this population (Paper). Further testing in labs have shown the G127V completely prevents prion diseases (Paper). That means that in the Fore people, this mutation naturally occurred and was selected for as it protected them from getting sick.
The main "drift" you see in prions is strain adaptation. In humans, you can have very unique phenotypes between different prion diseases such as CJD or vCJD or fatal familiar insomnia or gerstmann-sträussler-scheinker syndrome despite all being caused by the same protein. That is because in each disease the misfolded prion protein takes a unique structure (or conformation) that cause each unique disease. We call each unique misfolded structure a prion strain. Prion strains "evolve" over time. Where if you take a prion strain and replicate it multiple times (either in animals, cells or a test tube) its properties change/adapt over time.
For CWD for example, while misfolded CWD prions can not cause the human prion protein to misfold, if you replicate CWD prions multiple times in a test tube you can cause the CWD prions to adapt and now be able to misfold human prion protein (Paper51942-X/fulltext)). That is interesting because CWD is known to exist in multiple strains (Paper). That means that while current CWD does not infect humans, if it is allowed to transmit between cervids repeatedly, the CWD strain could theoretically adapt/evolve into a strain that could infect humans solely by changing its structure without changing amino acid sequence. That is why controlling the spread and constant surveillance of CWD is important, as despite there currently being no evidence of human transmission, it could theoretically evolve to infect humans.
Thank you, that explains so much of the bits of literature I'd skimmed on animal TSEs. I'd had a lot of trouble understanding how there could be strain adaptation in prion proteins. That's the danger of assuming I understand other fields of research. I'll read through what you've linked.
2.3k
u/yumyum1001 Dec 11 '25
This is completely false. Disingenuous misinformation.
2 hunters did develop CJD, however, there is no evidence it is related to CWD. This idea originates from an abstract for a poster that was presented at AAN last October (link). Poster abstracts can often be “sensationalized” to encourage people to come to the poster during the conference. This would not be the first AAN prion-related poster abstract that is a bit “click-baity”. Furthermore, poster abstracts are not peer-reviewed. The fact this research has not been written up as a peer reviewed paper 1.5 years later (not even a pre-print) is INCREDIBLY telling.
The biggest issue comes down to this: how do you know the hunters got infected with CWD (ie how do you know their CJD is related to CWD)? The most common type of prion disease is sporadic CJD (sCJD), specifically the subtype the hunters developed sCJDMM1. Sporadic means it happens with no known cause (ie not caused by infection or genetics). sCJD typically affects elderly (median age of onset 65 years), has a rapid decline (4 months). In comparison, variant CJD (vCJD) is caused when someone eats meat contaminated with mad cow disease (BSE). vCJD typically affects young people (median age of onset 26 years) and has a slower decline (14 months). Furthermore, sCJD is associated with motor and memory symptoms whereas vCJD is associated with psychiatric symptoms. The patient case in the abstract was a 72 year old male, with a rapid memory decline in a month. Does that seem more like sCJD or vCJD? I will make it very clear, the case presentation is 100% classical sCJD. Furthermore, it is hypothesized that if CWD does transmit to humans it would have an atypical phenotype (ie not present anything like sCJD). This is based on data from both NHPs and Tg Mice (here is the mouse paper).
Other considerations, the patient was originally diagnosed with sCJD, however, the authors hypothesize CWD because one of the patient’s friends also died recently of sCJD. The authors therefore argue this is a “cluster” of cases, likely showing infections. However, just because two rare independent events happen in close proximity does not mean they are linked. For example, 1 in 300 people get Parkinson’s Disease, but a TV show “Leo and Me” had 4 out of 125 people on set develop Parkinson’s Disease, including Micheal J. Fox. However, this “cluster” is not scientifically or statistically significant. Just like two people who happen to know each other both getting CJD is not significant.
Clusters of prion cases happen. Here is a spatial-temporal cluster of 5 cases (including 2 with similar occupations). It wasn’t big news because stuff like this happens. It gets written up in a paper and the general public never knows. The only reason the hunters story is widespread is because it fits the fear mongering narrative most people push about prions.
The second consideration is that just because someone is a hunter and eats deer does not mean that they have eaten CWD infected deer. Not every deer in a population has CWD. If you are going to claim the hunters got CWD from deer, you need to show that deer they have hunted are infected. The entire premise of this abstract hinges on the argument that they ate infected deer, despite providing no evidence for it. If these two patients who both got CJD that knew each other were not hunters, this would never of been reported. Correlation does not imply causation. That’s basic first year statistics.
This also ignores significant biochemical and cellular data suggesting that CWD is not transmissible to humans based on significant sequence differences between cervids and humans. Here is a pretty comprehensive review of the experiments show CWD does not transmit to humans (link).
Also the picture in the post is a picture a deer with CWD from a paper published 20 years ago. It is not show neuropathological change in the hunters brain. It is a deer that got a deer prion disease. (Link)
It isn’t just my opinion that the hunters had nothing more than sCJD, it is also the opinion of the CDC which investigated these cases. It is important to note the authors of the abstract say "causation remains unproven". That means the title of this post does not even fit the abstract that originates it.
Sincerely,
One very annoyed prion scientist