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/cloisteredsaturn]

Prion diseases are rare because of the method of transmission - you have to consume the affected tissue, usually the brain. See: CJKD, BSE, kuru

Those animals who do get infected usually die pretty quickly. Those prions are misfolded proteins so they’re going to degrade eventually, and won’t spread to another organism unless consumed.

They’re not transmitted via aerosols, air droplets, or on surfaces like, for example, cold and flu viruses are.

[u/SquirrellyBusiness → u/cloisteredsaturn]

Chronic wasting disease is excreted and transmitted on surfaces and persistent in the environment for years. 

[u/cloisteredsaturn → u/SquirrellyBusiness]

It isn’t transmissible to humans afaik (but people should still take precautions if they hunt deer, moose, elk, etc) but even with the environment being contaminated, another cervid still has to consume those infected materials.

I do remember reading somewhere that those prions can remain in the environment for decades. Poor deer.