The origin of the Wuhan coronavirus has always seemed a little underpants gnomes business-plan like with vagueness on some of the middle parts. I think it is fairly certain that the original reservoir from which the virus developed was a colony of horseshoe bats. And there seems little doubt that a particular Wuhan seafood animal market (a “wet” market) was the place where it really started to spread to the rest of Wuhan and thence the world.
The bit in the middle. The bit where the virus mutated and crossed over from bat to human host is less clear. It could be via pangolins as part of a scenario where the virus travels from bat to pangolin, encounters and merges with a different pangolin coronavirus and then spreads to humans. this is pertty standard virus behavior, for example flu viruses do this cross species merging all the time with flu strains jumping between humans, pigs and birds and mixing with other strains as they do. In fact that was the cause of some of the previous Chinese originated flu epidemics such as the 2009 swine flu one. But for the theory to hold in this case we would need a place, a market stall perhaps, where pangolins and bats were next to each other and that is something that there isn’t much evidence of.
But there are other issues. Many people have noticed that Wuhan has two major research centers and this has resulted in a number of theories that the virus was a leaked bioweapon or similar. But the leaked bioweapon theories don’t really explain why there seems to have been a major nexus in one particular wet market.
At the National Review, Jim Geraghty does a good job of giving background and covering the evidence to date. This includes a link to his earlier article where we learn that horseshoe bats with coronaviruses were a research subject at one of the institutes. But there’s still a bit of handwavium in the path from institute to market and on how the bat virus got a well known sequence from a pangolin virus.
So here’s my theory.
I believe the virus was probably created in a research institute – most likely the Wuhan Center for Disease Control & Prevention (WHCDC) – as part of the ongoing research into coronaviruses. My guess is that some clever researcher did a CRISPR-like replacement of a section of the original bat virus with the bit from the pangolin virus to create this new one. Why would a researcher do that? One reason would be to prove that they really had decoded the genome sufficiently well that they knew what part controlled where it bound to in mammalian cells and they changed it to bind to ACE2 from whatever it was in the bat version.
This also explains how the Chinese were so quick to release the full sequence of the virus (it’s easy to do that if you created it yourself).
But, you say, that still doesn’t get us to the market. Well now. Let us assume the researcher has done his edit, infected a bunch of bats and seen that it spread from one to another and still bound to ACE2. Great. Can write paper. But what to do with the infected bats? Who mostly probably haven’t died bet who are still full of the virus because the testing can be done pretty soon after infection occurs.
Obviously as a researcher you simply send a note to facilities to ask them to remove the bats. You assume the facilities staff will kill them and dispose of the bodies. But this is the PRC. I suspect the chances are high that some lowly paid janitor type sees an opportunity to make a quick yuan or thousand by not actually killing all of them but having a few fall out the back of the cage into a sack in the hands of a buddy who knows someone who knows a guy in the wet market that deals in exotic meat and has customers for bat soup.
This gets us infected and infectious live bats with the right coronavirus into the market where their blood and other bits can be spread around to infect people. But just because most of the infected bats went to the market doesn’t mean that all of them did or that they went there directly. Chances are that they got stored in someone’s apartment or garage or back garden shed or similar and quite possibly numerous grandmas, grampas and other relations, friends and acquaintances of the various middlemen in the chain got to see, poke and maybe even cook and eat some of these bats. And probably some of them got a bonus coronavirus as part of the deal.
So does that explain the middle bit convincingly?