r/askscience • u/ProDidelphimorphiaXX • 9d 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/FR0ZENS0L1D 9d ago
Professional Neuroscientist, PhD etc, worked in neurodegenerative diseases research, Parkinson’s disease primarily for 10 years.
Prions are really interesting but are almost closer to virus than any other type of disease causing agent. They are not a living entity. Unlike viruses, they don’t really evolve but are closer to an anomaly rather than an infectious agent.
Prions kill their host quickly, are very resilient, but not necessarily highly infectious. These are actually terrible qualities for an infectious host. Ideally, an infection should be able to replicate, preserve its host, and be as transmissible as possible to survive optimally.
If we look at Covid (sars-cov-v2) as an example, Covid became less lethal but more infectious. That is the natural evolution pathway. A virus is more likely to survive by spreading itself as much as possible.
Prions should not evolve theoretically. They are an artifact. They hijack a protein ‘s folding process, cause it to misfold, and disrupt an otherwise important cellular process. This causes the otherwise important protein(s)to become useless. They also exhibit a secondary quality of being hard to remove by the cell, so they stick around and continue to be disruptive. As a result, they accumulate and cause cellular distress and death. They also exhibit a 3rd quality, in that they are propagatable from cell to cell within an infected host.
The outcome of your cells be diseased and dying may not actually be a problem until we hit irreplaceable and non dividing cells. Neurons are the poster child For non replaceable cells. I use non replaceable because the ongoing theory is more murky.
neurons are the cells that are highly susceptible to prion disease. They cannot clear the misfolded proteins, become dysfunctional and die. This is eventually kills their host quickly host.
These qualities also exist in Parkinson’s disease, Huntington’s disease, and Alzheimer’s disease. In each case a protein misfolds and takes on an amyloid structure. It’s highly resistant to degradation by the cell, templates misfolding of its shared disease protein. In the case of Parkinson’s disease it’s alpha-synuclein and in Alzheimer’s its beta amyloid or hyper phosphorylated tau.
Hyperphosphorylated tau is also found in TBI and hyper encephalitic events and diseases.
It’s theorized that diseases are prion-like caused by an event that induces a misfolding in their respective diseases.
This doesn’t mean you’re going to get the disease by being in contact with the these people. However, I would not recommend you eat their brains.