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> In a lab environment the virus is repeatedly exposed to human cells and gets better at infecting human cells with each iteration. That is just replicating wh
by lamontcg 4y ago
> In a lab environment the virus is repeatedly exposed to human cells and gets better at infecting human cells with each iteration.
That is just replicating what nature does when it hops from individual to individual. Nature has billions of animals to do serial passage through.
And we still don't know that the species jump happened in the market, and I'm somewhat skeptical of the claims of this author. I tend to think it was circulating in rural Hubei, probably coinfecting domestic animals and people, getting better and better at infecting people until the market event happened which was where it found a densely packed human population where it spread with R0 significantly greater than 1 and took off. There's no evidence of that though because when the grandparents of farmers in rural villages die of pneumonia nobody bothers collecting samples because that's normal.
And we only noticed it when it started to efficiently infect human beings because that is when the pandemic started. The initial poor cryptic spread between humans and animals before that wouldn't have been detected because poor spreading couldn't cause the pandemic to start.
And we know that its possible for the virus to jump backwards and forwards between humans and minks, so the idea that an intermediate animal reservoir would have been infected with this virus and would have repeatedly attempted to jump to farm workers until it finally got good at spreading in humans is not that far fetched at all. Then the intermediate animal host becomes a massive bioreactor in close contact with humans, giving it many opportunities to roll the dice until it finds a combination that unlocks its pandemic potential, and then the first time it was transported into a dense human population it takes off.
There could be a hundred other viruses in animals in China all knocking on the door, occasionally infecting humans and not being good at it all right now, happening every day in China. This one was very good at infecting humans, along with being very good at infecting all kinds of other animals (mink, deer, dogs, cats, etc) because in order to cause a pandemic it had to be good at that, if it was bad at that it wouldn't have happened. It is like the anthropic principle--the virus seems incredibly lucky, because it had to be.
- Consultant32452 4y agoIt would actually be extremely unlikely for a virus that is "medium good at spreading to humans" to stay in an isolated location, especially one that spreads asymptomatically.
- lamontcg 4y agoIf it spreads asymptomatically though isn't that "good" at spreading rather than "medium"? SARS-1 disn't have a presymptomatic infectious phase and the peak of symptoms was roughly the peak of infectiousness, and it was mostly severely virulent, and it didn't produce a global pandemic and was controllable. To have an uncontrollable pandemic you really need that silent spreading, so the pandemic virus that emerges necessarily has that property from the "start".
- Consultant32452 4y agoHow does a virus that's pretty good at spreading through humans but not yet amazing at spreading through humans stay in an isolated region for months or even years?
- mcguire 4y agoWhat does "isolated region" mean to you?
- Consultant32452 4y agoThe example given by the other poster is rural Hubei.
- lamontcg 4y agoI don't think it would, and I don't know why you'd think I'm suggesting that.
- Consultant32452 4y ago>I tend to think it was circulating in rural Hubei, probably coinfecting domestic animals and people, getting better and better at infecting people until the market event happened which was where it found a densely packed human population where it spread with R0 significantly greater than 1 and took off. How would a virus that's medium good at infecting humans, but not yet amazing at infecting humans, stay in rural Hubei for years without escaping?