4 ms·

I think it largely comes down to there being no benefit to the prion. It’s more of a lightly continuous sort-of-poison than an actual actor looking for its own

by donatj 5y ago

I think it largely comes down to there being no benefit to the prion. It’s more of a lightly continuous sort-of-poison than an actual actor looking for its own reproduction. Viruses and bacterias existence depends on reproduction. Prions just kinda appear naturally from folding errors. They don’t “want” to exist, even to the minimal extent of a virus, they just happen.

Victerius 5y ago
I like to tell people that early humans lived in close contact with animals for hundreds of thousands of years, and until a few generations ago, when most people were still farming for a living. If prions had the potential to end the human race, they would already have.
- XorNot 5y ago
  The slight problem there is, prions probably did end a bunch of tribes which were sufficiently local - and then left the area alone long enough that the prion contamination in the environment broke down. Today we have international animal shipping and trade, and global distribution. Prions are able to spread from exposure to shared pastures. A couple years of contamination used to be no big deal - today, if missed, it can spread all through the food supply.
  - darkerside 5y ago
    I always wonder how much more truth there is to haunted houses and forbidden lands than we think. Just superstition? Maybe, but maybe not.
  - Gare 5y ago
    It is hypothesised that Kuru (and vCJD) in some individuals (due to genetics) might take 40-50 years to develop if introduced through intestine. Well after the individual had a chance to reproduce.
- phreeza 5y ago
  The advent of agriculture and animal husbandry is generally thought to be much more recent than your comment makes it sound. More like ten thousand years ago.
- ajuc 5y ago
  I think prions are a bigger problem in crowded single-species environment than in comparatively sparse mixed-species pre-industrial world. In particular when you feed cows proteins made from dead cows it's making it more likely to create prion problems than when wild animals live in small herds in forests (and the ones that are sick are killed by predators or starvation before they can infect others more than likely).
  - lazide 5y ago
    Feeding the output back into the input definitely makes it a bigger problem, however Chronic Wasting Disease in Elk and Dear in North America is becoming a huge problem and is a prion disease, and they’re living wild. So it doesn’t require it, it just increases the odds (and they don’t eat each other to spread it - it’s highly infectious and demonstratively infects if they share browsing/grazing land). It doesn’t appear to spread between them and humans, but it definitely makes me nervous.
- mschuster91 5y ago
  We're actually having a worse situation re/ animals than our ancestors. We nowadays cram farm animals in stables so tightly that without antibiotics and medical treatment the animals would almost immediately perish. Our farms and our animal "care" practices have been the breeding ground for all recent global pandemics (swine flu, bird flu, SARS/MERS/SARS2). Not to mention the conditions that farm and slaughterhouse workers have to work and live in (as evidenced by massive COVID outbreaks). The chance of any infectious agent "jumping the species" due to cramped conditions or because of exposure of workers to contaminated animal parts in unclean slaughterhouses is immense - the current SARS-CoV-2 pandemic in my opinion is a warning signal of something much worse to come, and no matter what kind of agent it will be, we're pretty much screwed. Half the population or more of the world doesn't believe in vaccination, a quarter or more don't have access to vaccines or any kind of modern medicine at all, we are already running out on reserve antibiotics...
arghwhat 5y ago
Virus does not "want" to exist either - they just happen. There is no success criteria or will, just a structure that happens to cause self-replication, with variants that cause more aggressive replication being more present and common. Prions are in that sense no different - they are just less successful.
- donatj 5y ago
  I think it’s debatable as to the meaning of “want” of non-thinking/non-living things. Viruses continued existence depends on reproduction however, which they’ve been doing for billions of years. That’s a “want” in my book as far as something seemingly inanimate can want. Viruses that don’t “want” reproduction fail to do so and disappear.
  - andybak 5y ago
    Still not sure I get the distinction with prions that you're making. The essential idea is roughly "we end up with more of the things that replicate more". Despite the redundancy, there is a crucial idea in here. If we allow the use of the word "want" metaphorically then anything that replicates "wants" to reproduce including memes, crystals, prions and computer viruses. Maybe you're just saying that a prion isn't as good at replicating as a virus? It seems like a difference of degree rather than kind.
    - __s 5y ago
      They may be suggesting that prions don't have a large space to evolve within through random mutation
    - tomxor 5y ago
      > Maybe you're just saying that a prion isn't as good at replicating as a virus? It seems like a difference of degree rather than kind. They are qualitatively different. A virus infects a cell, and critically, can quickly adapt (through random mutations) in an unthinking war between the various forces of the immune system and transmission mode efficacy; A prion does not evolve, it's a misfold of a single type of protein. If you want to compare it to a virus, it's like a virus that is incapable of replicating anything other than an exact copy - and can also only replicate itself using a particular cell (one type of protein). Why the human body cannot effectively defend itself against particular propagating misfolded proteins is a mystery to me though... perhaps it's too low level to be identified by the immune system as something to attack, much like a poison.

by donatj 5y ago

Victerius 5y ago

I like to tell people that early humans lived in close contact with animals for hundreds of thousands of years, and until a few generations ago, when most people were still farming for a living. If prions had the potential to end the human race, they would already have.

XorNot 5y ago
The slight problem there is, prions probably did end a bunch of tribes which were sufficiently local - and then left the area alone long enough that the prion contamination in the environment broke down. Today we have international animal shipping and trade, and global distribution. Prions are able to spread from exposure to shared pastures. A couple years of contamination used to be no big deal - today, if missed, it can spread all through the food supply.
- darkerside 5y ago
  I always wonder how much more truth there is to haunted houses and forbidden lands than we think. Just superstition? Maybe, but maybe not.
- Gare 5y ago
  It is hypothesised that Kuru (and vCJD) in some individuals (due to genetics) might take 40-50 years to develop if introduced through intestine. Well after the individual had a chance to reproduce.
phreeza 5y ago
The advent of agriculture and animal husbandry is generally thought to be much more recent than your comment makes it sound. More like ten thousand years ago.
ajuc 5y ago
I think prions are a bigger problem in crowded single-species environment than in comparatively sparse mixed-species pre-industrial world. In particular when you feed cows proteins made from dead cows it's making it more likely to create prion problems than when wild animals live in small herds in forests (and the ones that are sick are killed by predators or starvation before they can infect others more than likely).
- lazide 5y ago
  Feeding the output back into the input definitely makes it a bigger problem, however Chronic Wasting Disease in Elk and Dear in North America is becoming a huge problem and is a prion disease, and they’re living wild. So it doesn’t require it, it just increases the odds (and they don’t eat each other to spread it - it’s highly infectious and demonstratively infects if they share browsing/grazing land). It doesn’t appear to spread between them and humans, but it definitely makes me nervous.
mschuster91 5y ago
We're actually having a worse situation re/ animals than our ancestors. We nowadays cram farm animals in stables so tightly that without antibiotics and medical treatment the animals would almost immediately perish. Our farms and our animal "care" practices have been the breeding ground for all recent global pandemics (swine flu, bird flu, SARS/MERS/SARS2). Not to mention the conditions that farm and slaughterhouse workers have to work and live in (as evidenced by massive COVID outbreaks). The chance of any infectious agent "jumping the species" due to cramped conditions or because of exposure of workers to contaminated animal parts in unclean slaughterhouses is immense - the current SARS-CoV-2 pandemic in my opinion is a warning signal of something much worse to come, and no matter what kind of agent it will be, we're pretty much screwed. Half the population or more of the world doesn't believe in vaccination, a quarter or more don't have access to vaccines or any kind of modern medicine at all, we are already running out on reserve antibiotics...

arghwhat 5y ago

Virus does not "want" to exist either - they just happen. There is no success criteria or will, just a structure that happens to cause self-replication, with variants that cause more aggressive replication being more present and common. Prions are in that sense no different - they are just less successful.

donatj 5y ago
I think it’s debatable as to the meaning of “want” of non-thinking/non-living things. Viruses continued existence depends on reproduction however, which they’ve been doing for billions of years. That’s a “want” in my book as far as something seemingly inanimate can want. Viruses that don’t “want” reproduction fail to do so and disappear.
- andybak 5y ago
  Still not sure I get the distinction with prions that you're making. The essential idea is roughly "we end up with more of the things that replicate more". Despite the redundancy, there is a crucial idea in here. If we allow the use of the word "want" metaphorically then anything that replicates "wants" to reproduce including memes, crystals, prions and computer viruses. Maybe you're just saying that a prion isn't as good at replicating as a virus? It seems like a difference of degree rather than kind.
  - __s 5y ago
    They may be suggesting that prions don't have a large space to evolve within through random mutation
  - tomxor 5y ago
    > Maybe you're just saying that a prion isn't as good at replicating as a virus? It seems like a difference of degree rather than kind. They are qualitatively different. A virus infects a cell, and critically, can quickly adapt (through random mutations) in an unthinking war between the various forces of the immune system and transmission mode efficacy; A prion does not evolve, it's a misfold of a single type of protein. If you want to compare it to a virus, it's like a virus that is incapable of replicating anything other than an exact copy - and can also only replicate itself using a particular cell (one type of protein). Why the human body cannot effectively defend itself against particular propagating misfolded proteins is a mystery to me though... perhaps it's too low level to be identified by the immune system as something to attack, much like a poison.