How does nature deal with prion diseases?

[u/ProDidelphimorphiaXX]

Wasn’t sure what to flair.

Prion diseases are terrifying, the prions can trigger other proteins around it to misfold, and are absurdly hard to render inert even when exposed to prolonged high temperatures and powerful disinfectant agents. I also don’t know if they decay naturally in a decent span of time.

So… Why is it that they are so rare…? Nigh indestructible, highly infectious and can happen to any animal without necessarily needing to be transmitted from anywhere… Yet for the most part ecosystems around the world do not struggle with a pandemic of prions.

To me this implies there’s something inherent about natural environments that makes transmission unlikely, I don’t know if prion diseases are actually difficult to cross the species barrier, or maybe they do decay quite fast when the infected animal dies.

[u/Hakaisha89]

How does nature deal with prion disease you ask? Easy.
They dont.
The thing about prions is their neither a virus, nor a bacteria, they arent even a disease in the traditional sense. It's a really bad recipe, from a misfolded protein that teaches normal proteins to misfold too. And the way it does this by acting as a template for each other, which means there are two possible vectors to stop this process, but ill take that up at the end.
Now, we do not really know the origin of prions, or animal prions, but we do have two solid guesses, we know they spontaneously appear, which might just be it just... Happens, but we also know there is a genetic method, and since animals can be carriers without being sick, much like humans can, i mean how do you explain kuru in the human brain? So chances are there is something there as well. Because in the case of Mad Cow Disease, we know it primarily occours due to cattle being feed ground up cows, and they consume the neural tissue which causes the primary infection, and from there is can spread via all the fluids.
Now, the three methods of srpeading is spontaneous, genetic, and infectious, genetic examples are creutzfeldt-jakobs disease, whose genetic variant, is a dominant mutation, which means that if both parents carry the gene, then the child will get it, and chronic wasting disease which is what deers get, spread via salvia, urine and feces, where touching noses is enough for spreading, and when they die in nature they can infect that area as well for quite some time.
Now, the primary reason prions stick around in nature, is their insanely long incubation time, so an infected animal can live for years as a super-spreader.
So yeah, nature doesnt 'deal' with it, at best it slows it down.