Pangolins, link to SARS and Corona viruses (1 Viewer)

Deb Burhinus said:

Thanks for this James.

I have a question, is there a possibility that the ‘novel’ coronavirus is actually from a milder mutated form of SARS or even MERS - and so had already made the ‘jump’ to humans without the help of an interim third host - or (ok 2 questions ) could another human coronavirus be the missing link - (ie a ‘piggy-back’ mutation) rather than eg pangolins. If coronaviruses can leapfrog using other viruses, given the number of cold viruses circulating that could be a worrisome thought?

ps some reading for John
https://www.thetrumpet.com/22131-chinas-test-tube-pandemic

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I’m not quite sure I understand the questions, but I don’t think there is any possibility of the involvement of any non-SARS coronaviruses (eg MERS) let alone non-coronaviruses. And no reason to think SARS-CoV-1 was involved in any way. Basically SARS-CoV-2 is very similar to the horseshoe bat SARS strain RaTG13 and where it isn’t it’s mostly very similar to the pangolin CoV. So it’s probably a cross between two pretty closely related type 2 SARS corona viruses. The only unique element is the furin cleavage site which could have evolved through natural selection. Remember that probably the original leaps from bats to the intermediate hosts probably occurred decades ago.
James

jurek said:

It is probably because bats live in crowded colonies so their pathogens tend to be very virulent.

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What I've read is that it's actually insects that carry a lot of virulent pathogens from a variety of sources, and bats eat a variety of insects. (I just checked, the horseshoe bat in question is indeed insectivorous.) So they've evolved a rather special metabolism that's very tolerant/resistant to that... but we have not. Perhaps the worst possible thing one could eat.

Nice article on bats and viruses here
https://www.sciencedaily.com/releases/2020/02/200210144854.htm

James

This is a good article on the complexity of the issues:
https://www.theguardian.com/world/2020/mar/28/is-factory-farming-to-blame-for-coronavirus
See also this article that it references on wet markets:
https://theconversation.com/why-shutting-down-chinese-wet-markets-could-be-a-terrible-mistake-130625