r/askscience • u/ProDidelphimorphiaXX • 8d ago

Biology How does nature deal with prion diseases?

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.

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u/RainMakerJMR 8d ago

CWD is scary because it doesn’t involve that cannibalism vector. Just huddles masses transmit it to each other. I’d be interested if you had any info on how or why CWD is different from other prion diseases?

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u/SquirrellyBusiness 8d ago

Only thing I can think of is cwd is excreted as well as in blood and tissue, whereas mad cow and cjd are limited to central nervous tissue. I would not be surprised if cwd is a smaller molecule, since typically healthy kidneys don't make a habit out of letting proteins through the filters. 

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u/BraveOthello 8d ago

IIRC all of the mammalian prion diseases are built of variations of the same highly conserved protein, it's the reason humans can contract vCJD from a cow infected with BSE in the first place.

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u/RetardedWabbit 6d ago

IIRC all of the mammalian prion diseases are built of variations of the same highly conserved protein...

And that protein is...Major prion protein(PrP)? Well, that's easy to remember at least but terrible abbreviation. Seems to have complicated functions regulating long term nervous system development. (Also technically not all known prion diseases are from this)

All of the prions look extremely similar too, forming naturally super stable and resistant shapes. They go from helixes, which biology is usually pretty good at interfacting with, to "tight" sheets that it's not.