The World Health Organization reprimanded Chinese officials on Friday for rejecting research that could link Covid’s origins to wildlife, questioning why data had not been made available for three years. before and why it was lost.
Before the Chinese data disappeared, an international team of virus experts downloaded and began analyzing the study, which appeared online in January. They say it supports the idea that the pandemic may have started when trading was illegal raccoon dog infected people at the Wuhan seafood market.
But the gene sequence was removed from scientific databases after experts offered to collaborate on analysis with their Chinese counterparts.
Dr Tedros Adhanom Ghebreyesus, director general of the WHO, said: “These data could have been — and should have — been shared three years ago. The missing evidence now “needs to be shared with the international community immediately,” he said.
According to experts who are reviewing it, the study offers evidence that raccoon dogs, fox-like animals known to spread coronavirus, left DNA in the same place in the Wuhan market where the genetic signature was found. transmission of the new coronavirus was also detected.
To some experts, that finding suggests that these animals may have been infected and may have transmitted the virus to humans.
With the huge amount of genetic information pulled from the swabs of animal cages, carts and other surfaces at the Wuhan market in early 2020, genetic data has become the focal point of virology experts’ relentless predicted since they learned about it a year ago in a paper by Chinese scientists.
A French biologist discovered gene sequences in a database last week, and she and a team of colleagues have begun mining them for clues to the origins of the pandemic.
That group has yet to release a paper outlining the findings. But the researchers analyzed material for the WHO advisory group studying the origins of Covid during a meeting this week, which also included a presentation by Chinese researchers on the same data.
Sarah Cobey, an epidemiologist and evolutionary biologist at the University of Chicago who was not involved, said the analysis appeared to contradict earlier arguments by Chinese scientists that samples taken from market positive for coronavirus was transported by sick people alone. in the latest analysis.
Dr Cobey said: “It is very unlikely to see such a large amount of animal DNA, particularly raccoon dog DNA, mixed with virus samples, if it were simply human infection. “.
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Questions remain about how the samples were collected, what exactly they contained, and why the evidence disappeared. To the ambiguity, many scientists reacted cautiously, saying that it is difficult to evaluate the study without seeing the full report.
The idea that a lab incident could inadvertently trigger a pandemic has been at the center of renewed interest in recent weeks, thanks in part to a new perspective. intelligence assessment of the Department of Energy and hearing led by the new leadership of the Republican Party.
But some virologists who were not involved in the latest analysis say what is known about swabs collected at the market strengthens the case that animals sold there caused the pandemic.
“That’s exactly what you would expect if the virus emerged from one or more intermediate hosts on the market,” said Dr Cobey. “I think ecologically, this is almost a closed case.”
Dr Cobey was one of 18 scientists who signed an influential letter in the journal Science in May 2021 calling for serious consideration of a scenario in which a virus could spill out of a lab. in Wuhan.
On Friday, she said lab leaks continue to pose enormous risks and require more oversight of studies of dangerous pathogens. But Dr Cobey added that the accumulation of evidence – regarding the clustering of human cases around the Wuhan market, the genetic diversity of the virus there, and now data on raccoon dogs – reinforced the market-origin case.
New genetic data does not appear to prove that a raccoon dog has been infected with the coronavirus. Even if that were the case, it’s still possible that another animal may have passed the virus on to humans, or even that someone infected with the virus could have passed the virus on to a raccoon dog.
Several scientists emphasized those points on Friday, saying the new genetic data did not significantly alter the discussion about the origins of the pandemic.
“We know it’s an indiscriminate virus that infects many species,” said David Fisman, an epidemiologist at the University of Toronto who also signed the May 2021 letter in the journal Science.
Chinese scientists have come up with a learn in February 2022 to see samples on the market. Some scientists speculate that the Chinese researchers may have posted the data in January because they were asked to provide them as part of a review of their research by a scientific journal.
Chinese research has suggested that the virus-positive samples came from infected people, not from animals sold on the market. That fits a story long spread by Chinese officials: that the virus arose not only from outside the market but also from outside the country.
But the Chinese report left clues that viral material at the market was mixed with genetic material from animals. And scientists say the international team’s new analysis illustrates an even stronger link with animals.
“Scientifically, that doesn’t prove that raccoon dogs are the source, but it certainly smells like it,” said Jeremy Kamil, a virologist at Louisiana State University Health Science Center, Shreveport. like infected raccoons at the market.
“That raises more questions about what the Chinese government actually knows,” he added.
Scientists warn that it is not clear that genetic material from the virus and from the canine raccoon was deposited at the same time.
Depending on the stability of genetic material from viruses and animals, “they could have been deposited there at very different times,” said Michael Imperiale, a virologist at the University of Michigan.
However, Dr. Arturo Casadevall, an immunologist at the Johns Hopkins Bloomberg School of Public Health who co-authored a recent study with Dr. Imperiale examining the origin of the coronavirus, says there is a link between the material and the virus. Whether animals and viruses still add more evidence of the spread of viruses. natural spillover events.
“I would say it reinforces the idea of animal-to-human transmission,” he said, “i.e. the idea that it came from an animal at the market.”
In the absence of animals actually spreading the virus to humans, assessing the source of an outbreak will always involve weighing the probabilities, said Dr. Casadevall. In this case, the animals sold at the market were removed before the researchers started taking samples in early 2020 so the culprit could not be found.
Tim Stearns, dean of graduate and graduate studies at Rockefeller University in New York, says the latest finding is “an interesting piece of the puzzle,” though he says it’s “not the end in itself.” explicitly and emphasizes the need for further investigation. Thorough investigation.”
For all the missing elements, some scientists say the new findings highlight the amount of information scientists have gathered about the beginning of the pandemic, including the home addresses of first patient and sequence data from the market.
Theodora Hatziioannou, a virologist at Rockefeller University, says it’s important that the raw data be made public. However, she said, “I think there is a lot of evidence of market origin right now.”
And the latest data, she said, “makes this even more unlikely.”
Felicia Goodrum, an immunologist at the University of Arizona, says finding the virus in actual animals would be the strongest evidence of market origin. But finding virus and animal material in the same swab is close.
“For me,” she said, “this is the next best thing.”
