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I believe that: 1. The closest known animal viruses to human SARS-1 were found in civet cats in 2003, within about a year of the first discovery of the virus i

I believe that: 1. The closest known animal viruses to human SARS-1 were found in civet cats in 2003, within about a year of the first discovery of the virus in humans. 2. No animal viruses closer to SARS-1 have since been discovered. Dr. Shi discovered various viruses in bats that we believe are ancestral to SARS-1, including WIV-1 in 2013. This is significant because we believe SARS-1 evolved primarily in bats, but those viruses have lower genetic identity with SARS-1 than does the virus found in the civets. If you disagree, please link a paper. Based on the above, I don't understand why you'd think 2013 is the important date. Within about a year of the emergence of both of the previous two novel coronaviruses in humans (SARS-1 and MERS), a near-identical virus was discovered in animals (civets and camels). This is suggestive but not conclusive evidence that those animals first infected humans, and strong evidence that those viruses existed in nature--somewhere, even if not exclusively in those animals--before they emerged in humans. For SARS-CoV-2, no such evidence has yet been found. This doesn't prove that SARS-CoV-2 is of unnatural origin, and I assume you'll mention the uncertainty in Ebola's zoonotic hosts shortly; but I don't see how anyone could treat that as irrelevant, except out of willful blindness.

lamontcg 5y ago
Discovery of WIV1: [Isolation and characterization of a bat SARS-like coronavirus that uses the ACE2 receptor](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5389864/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5389864/) WIV1 grows in primary human airway epithelial cell cultures: [SARS-like WIV1-CoV poised for human emergence](https://www.pnas.org/content/113/11/3048 https://www.pnas.org/content/113/11/3048) > Together, the data demonstrate that the WIV1-CoV spike can mediate infection of human airway cultures with no significant adaptation required. And thanks for putting words in my mouth but no, I'm not confusing those with MERS.
- tripletao 5y ago
  I didn't mean to suggest that you were confusing anything with MERS. I just brought MERS up to show that not only had we found an animal infected with SARS-1 within about a year of its emergence in humans, but we'd also found such an animal for MERS, on a similar timescale. This means that SARS-CoV-2 is the 1/3 for which we haven't, not impossible just by chance but slightly more surprising than just 1/2. And yeah, you'd mentioned WIV-1 above, and I'd assumed that's what you meant from the 2013 date. I noted this in point (2) of my grandparent comment. I just don't understand why you think that's more significant than finding the near-identical virus in civets. The SARS-1 civets might not have first transmitted SARS-1 to humans, but the WIV-1 bats definitely didn't--they're very different viruses, and while WIV-1 might indeed be able to infect humans it's definitely not what caused the actual outbreak. So why pick 2013 and not 2003?
  - lamontcg 5y ago
    We have no proof that civets gave us SARS-1 and not the other way around. Since it was also found in raccoon dogs, ferret badgers and domestic cats which one of those was the actual intermediate animal? Civets were just the first identified. Either one of them gave it to us and we gave it to the other three, or possibly we got it from bats and gave it to all four. AFAIK there's no conclusive phylogenetic analysis establishing which species got it from whom. MERS is much more obvious what happened.
    - tripletao 5y ago
      I think you're strictly right there. If they'd obtained sequences then they could have built that tree; but as far as I know they didn't, perhaps because the cost of sequencing was higher back then. That's still more evidence than we have for SARS-CoV-2, though. With SARS-1 we had the additional evidence that some wildlife traders had antibodies, presumably from mild infections by related viruses in the animals they handled. There's again no genomic evidence to exclude "reverse zoonosis" there, but the timing seems to make that pretty unlikely. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1140695/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1140695/

lamontcg 5y ago

Discovery of WIV1: [Isolation and characterization of a bat SARS-like coronavirus that uses the ACE2 receptor](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5389864/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5389864/) WIV1 grows in primary human airway epithelial cell cultures: [SARS-like WIV1-CoV poised for human emergence](https://www.pnas.org/content/113/11/3048 https://www.pnas.org/content/113/11/3048) > Together, the data demonstrate that the WIV1-CoV spike can mediate infection of human airway cultures with no significant adaptation required. And thanks for putting words in my mouth but no, I'm not confusing those with MERS.

tripletao 5y ago
I didn't mean to suggest that you were confusing anything with MERS. I just brought MERS up to show that not only had we found an animal infected with SARS-1 within about a year of its emergence in humans, but we'd also found such an animal for MERS, on a similar timescale. This means that SARS-CoV-2 is the 1/3 for which we haven't, not impossible just by chance but slightly more surprising than just 1/2. And yeah, you'd mentioned WIV-1 above, and I'd assumed that's what you meant from the 2013 date. I noted this in point (2) of my grandparent comment. I just don't understand why you think that's more significant than finding the near-identical virus in civets. The SARS-1 civets might not have first transmitted SARS-1 to humans, but the WIV-1 bats definitely didn't--they're very different viruses, and while WIV-1 might indeed be able to infect humans it's definitely not what caused the actual outbreak. So why pick 2013 and not 2003?
- lamontcg 5y ago
  We have no proof that civets gave us SARS-1 and not the other way around. Since it was also found in raccoon dogs, ferret badgers and domestic cats which one of those was the actual intermediate animal? Civets were just the first identified. Either one of them gave it to us and we gave it to the other three, or possibly we got it from bats and gave it to all four. AFAIK there's no conclusive phylogenetic analysis establishing which species got it from whom. MERS is much more obvious what happened.
  - tripletao 5y ago
    I think you're strictly right there. If they'd obtained sequences then they could have built that tree; but as far as I know they didn't, perhaps because the cost of sequencing was higher back then. That's still more evidence than we have for SARS-CoV-2, though. With SARS-1 we had the additional evidence that some wildlife traders had antibodies, presumably from mild infections by related viruses in the animals they handled. There's again no genomic evidence to exclude "reverse zoonosis" there, but the timing seems to make that pretty unlikely. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1140695/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1140695/