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0 pointsDownGoat5y ago0 comments

Some virologists suggest that the common cold corona viruses that are endemic, might have been deadly when novel, and caused similar pandemics, but mutated to something less dangerous over time.

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dwd5y ago

It's not that they mutate specifically to less dangerous versions; rather the subtle variations that don't kill their host before spreading persist while the ones that are rapidly fatal quickly disappear when containment measures are put in place.

Which makes this one bad as it's infectious for a long time before there are symptoms or it kills the host - hence the panic.

djsumdog5y ago

I've wondered that too. What if in human pre-history (10,000+ years ago) modern rhinoviruses and coronaviruses that cause common colds, were once terribly deadly. We could just be the descendants of survivors who evolved immune systems that were able to deal with these viruses?

One of the techniques of trying to make vaccines is to attenuate it by exposing to to different hosts; so that it will mutate into a form that's less harmful to humans; kinda the opposite of what probably happened here, where a virus that was not deadly to either bats or pangolins but caused havoc when it got to us.

selectodude5y ago

SARS-2 isn't particularly dangerous for children. Most of them don't even have symptoms. Maybe all of our cold-causing coronaviruses are deadly when they present for the first time to an adult but since we all get them as children, our immune systems are better prepared.

akiselev5y ago

It need not even be pre-historical. Until indoor plumbing, germ theory, and modern medicine in general, infectious diseases were one of the few remaining modes of natural selection that humanity couldn't control. The usual solutions to nature's challenges like increasing density to allow for specialization and economies of scale or trading with neighbors just made the problem worse. Given how many people died due to the introduction of diseases to the Americas and the black plague in Europe, infectious diseases have definitely been a powerful driver of our evolution in the common era, let alone 10,000+ years ago.

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