23 ms·

It already has with the BSE crisis, and I'm not sure if we 100% understand how close to a much greater crises we came. I remember there was period in the UK bac

by jajag 2y ago

It already has with the BSE crisis, and I'm not sure if we 100% understand how close to a much greater crises we came. I remember there was period in the UK back in the nineties where there was the grim prospect of hundreds of thousands of cases - thankfully it never came close to that. And there are European countries where I still can't donate blood, because I lived in the UK during the outbreak.

giantg2 2y ago
"I'm not sure if we 100% understand how close to a much greater crises we came." That's basically my point. It doesn't seem like we changed our practices that much. I would have thought we'd test the animals, process them separately, etc.
- gustavus 2y ago
  My understanding is that one of the changes we made is we stopped feeding cow brains to other cows, which was the root cause of the problem.
  - consumer451 2y ago
    My personal pet theory was that prions are an evolutionary mechanism which prevents cannibalism in mammals. I know nothing about evolutionary biology, and I wonder if there is any chance that this is true.
    - sapiogram 2y ago
      I think your theory makes a lot of sense if you reverse the causality: Mammals have evolved to not engage in cannibalism to avoid prions. Other diseases as well, of course.
      - deleted 2y ago
        [deleted]
    - kaikai 2y ago
      One of the first thing you learn in evolutionary biology is that evolution doesn’t have intent.
      - consumer451 2y ago
        Yeah, I guess even I know better than that and should have chosen my words more carefully.
    - nrdvana 2y ago
      Also not a biologist, but as I understand it: Every living creature synthesizes proteins. Every time you synthesize a protein, there is a tiny tiny chance that it synthesizes "backward". Backward proteins are physically incompatible with "forward" proteins, and also increase the risk that more proteins synthesize backward. It leads to a cascade of errors where lots of proteins synthesize backward and the cells and internal structures can no longer function. It's like you fall apart due to half your Lego bricks being upside-down. And, this is all a statistical probability that could occur in any moment to any living organism. The evolutionary defenses are to break apart all incoming proteins and reassemble them yourself, and have a cycle of life that starts new organisms from scratch. Large carnivores can't hope to break apart every incoming protein, though. So, basically our lifespans and reproduction method of growing up from a single cell are the evolutionary defenses against the natural phenomenon of prions. But yes, prion disease is probably what forces all higher foodchain animals to avoid cannibalism.
      - gustavus 2y ago
        So that has raised an interesting question in my mind. But as far as I know the only significant case of prion disease amongst human beings, excluding CJD which seems to be generically determined, was the instance of Kuru among the Papau New Guinea tribes; however we know other societies practiced cannibalism at a certain scale such as the Aztecs in which people were eating other people all over the place, yet we don't have widespread evidence of Kuru. Is there something distinct about Brian tissue which puts it at a higher risk for prion disease formation?
        zdragnar 2y ago
        Just a bystander shooting from the hip, but does the fact that brain nerve cells aren't recycled and rebuilt but live as long as the person does mean they are more prone to accumulating bad proteins? Other tissue like skin or muscle that regularly break down and regrow would offer a lot more opportunity for the body to filter out the prions, but once in the brain cells, there's nothing for them to do but accumulate.
        rcxdude 2y ago
    - lazide 2y ago
      ‘Prevents’ is an odd way of putting it. A thing eating dead instances of its same family is already a near ideal situation for passing disease, no fancy evolutionary mechanism required. Frankly, hard to imagine a better one. If mammals needed a ‘anti cannibalism’ evolutionary mechanism there are plenty of other mechanisms - like disgust responses - that would actually prevent disease.
  - giantg2 2y ago
    There's also the non-typical BSE - or BSE that is spontaneous. Typically this only affects older cattle. The interesting thing is that for other prions like scapie and CWD are thought to spread through body fluids and feces and be available in the environment for years. But I don't see any of these concerns listed with BSE. Makes me wonder how much is guess work and how much is confirmed about any of them. But I suspect environmental contamination could be a possible vector. If spread through stuff like urine and feces, CAFOs could be a significant source. This could be a problem if they can be infected for years before symptoms arise, while time to market is 18 months.
- sigmoid10 2y ago
  There were lots of changes that permeated far beyond Britain. There was a time when every cow was tested in Germany if it was merely alive during the time when contaminated animal-based feed was going around, even if it wasn't fed anything like that. The EU only lifted general testing like 10 years ago - 20 years after the original outbreak. People have also completely stopped using the kind of feed ingredients that allow transmission of the disease to livestock intended for human consumption in most parts of the world. It was a shitty situation, especially in Britain, and many people there probably still carry the disease without knowing it because it can take up to 50 years to show symptoms. That's also the reason why many countries still won't allow you to donate blood if you lived in Britain at the time as the other comment mentioned. So saying that we didn't learn from it or changed nothing is just wrong. Another outbreak like the original one is basically impossible in the western world.

by jajag 2y ago

giantg2 2y ago

"I'm not sure if we 100% understand how close to a much greater crises we came." That's basically my point. It doesn't seem like we changed our practices that much. I would have thought we'd test the animals, process them separately, etc.

gustavus 2y ago
My understanding is that one of the changes we made is we stopped feeding cow brains to other cows, which was the root cause of the problem.
- consumer451 2y ago
  My personal pet theory was that prions are an evolutionary mechanism which prevents cannibalism in mammals. I know nothing about evolutionary biology, and I wonder if there is any chance that this is true.
  - sapiogram 2y ago
    I think your theory makes a lot of sense if you reverse the causality: Mammals have evolved to not engage in cannibalism to avoid prions. Other diseases as well, of course.
    - deleted 2y ago
      [deleted]
  - kaikai 2y ago
    One of the first thing you learn in evolutionary biology is that evolution doesn’t have intent.
    - consumer451 2y ago
      Yeah, I guess even I know better than that and should have chosen my words more carefully.
  - nrdvana 2y ago
    Also not a biologist, but as I understand it: Every living creature synthesizes proteins. Every time you synthesize a protein, there is a tiny tiny chance that it synthesizes "backward". Backward proteins are physically incompatible with "forward" proteins, and also increase the risk that more proteins synthesize backward. It leads to a cascade of errors where lots of proteins synthesize backward and the cells and internal structures can no longer function. It's like you fall apart due to half your Lego bricks being upside-down. And, this is all a statistical probability that could occur in any moment to any living organism. The evolutionary defenses are to break apart all incoming proteins and reassemble them yourself, and have a cycle of life that starts new organisms from scratch. Large carnivores can't hope to break apart every incoming protein, though. So, basically our lifespans and reproduction method of growing up from a single cell are the evolutionary defenses against the natural phenomenon of prions. But yes, prion disease is probably what forces all higher foodchain animals to avoid cannibalism.
    - gustavus 2y ago
      So that has raised an interesting question in my mind. But as far as I know the only significant case of prion disease amongst human beings, excluding CJD which seems to be generically determined, was the instance of Kuru among the Papau New Guinea tribes; however we know other societies practiced cannibalism at a certain scale such as the Aztecs in which people were eating other people all over the place, yet we don't have widespread evidence of Kuru. Is there something distinct about Brian tissue which puts it at a higher risk for prion disease formation?
      - zdragnar 2y ago
        Just a bystander shooting from the hip, but does the fact that brain nerve cells aren't recycled and rebuilt but live as long as the person does mean they are more prone to accumulating bad proteins? Other tissue like skin or muscle that regularly break down and regrow would offer a lot more opportunity for the body to filter out the prions, but once in the brain cells, there's nothing for them to do but accumulate.
      - rcxdude 2y ago
  - lazide 2y ago
    ‘Prevents’ is an odd way of putting it. A thing eating dead instances of its same family is already a near ideal situation for passing disease, no fancy evolutionary mechanism required. Frankly, hard to imagine a better one. If mammals needed a ‘anti cannibalism’ evolutionary mechanism there are plenty of other mechanisms - like disgust responses - that would actually prevent disease.
- giantg2 2y ago
  There's also the non-typical BSE - or BSE that is spontaneous. Typically this only affects older cattle. The interesting thing is that for other prions like scapie and CWD are thought to spread through body fluids and feces and be available in the environment for years. But I don't see any of these concerns listed with BSE. Makes me wonder how much is guess work and how much is confirmed about any of them. But I suspect environmental contamination could be a possible vector. If spread through stuff like urine and feces, CAFOs could be a significant source. This could be a problem if they can be infected for years before symptoms arise, while time to market is 18 months.
sigmoid10 2y ago
There were lots of changes that permeated far beyond Britain. There was a time when every cow was tested in Germany if it was merely alive during the time when contaminated animal-based feed was going around, even if it wasn't fed anything like that. The EU only lifted general testing like 10 years ago - 20 years after the original outbreak. People have also completely stopped using the kind of feed ingredients that allow transmission of the disease to livestock intended for human consumption in most parts of the world. It was a shitty situation, especially in Britain, and many people there probably still carry the disease without knowing it because it can take up to 50 years to show symptoms. That's also the reason why many countries still won't allow you to donate blood if you lived in Britain at the time as the other comment mentioned. So saying that we didn't learn from it or changed nothing is just wrong. Another outbreak like the original one is basically impossible in the western world.