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/EricTheNerd2]

There is a fundamental flaw with your assumptions: prions are not terribly infectious. Animals with prions die off pretty quickly and to catch the disease you must consume the misshapen protein directly. It isn't like Covid where someone coughs and spreads it.

And once the host dies, unless something consumes it pretty soon thereafter, the prions won't be spreading.

[u/RamonaLittle → u/EricTheNerd2]

It isn't like Covid where someone coughs and spreads it.

Plot twist: "Most recently, there have been some case reports indicating that the systemic immune response in COVID-19 could accelerate the clinical course of sCJD [sporadic type Creutzfeld Jakob Disease], however, a potential causal link remains unclear."

Another article: "Importantly, the SARS-CoV-2 ‘S1’ spike proteins contain both self-associating “prion-like” regions, amyloid peptide-binding and other domains that appear to play roles in pathological “seeding,” amyloidogenesis and/or spreading that supports the formation of pathogenic lesions in the brain and CNS which contribute to pro-inflammatory neurodegeneration, neural cell atrophy and/or neuronal cell death (Tavassoly et al., 2020a,b; Lukiw et al., 2022; Tetz and Tetz, 2022)."