The World Health Organization rebuked Chinese authorities on Friday for withholding scientific research that may link the origin of the coronavirus to wild animals called raccoon dogs, asking why the data was not available three years ago and why, after it was posted online in January. , could not be found now.
Before the Chinese data disappeared, an international team of virus experts downloaded and began analyzing the research. They say it supports the idea that the pandemic could have started when illegally traded raccoon dogs infected humans at the Huanan Seafood Wholesale Market in Wuhan, China.
But the gene sequences were removed from a scientific database after experts offered to collaborate on the analysis with their Chinese counterparts.
“This data could have been shared, and should have been shared, three years ago,” said Dr. Tedros Adhanom Ghebreyesus, WHO director-general. The missing evidence now “must be shared with the international community immediately,” he said.
According to experts reviewing it, the investigation offers evidence that raccoon dogs, fox-like animals known to transmit coronaviruses, had left DNA at the same spot in the Wuhan market where the genetic signatures of the dog were also discovered. new coronavirus.
To some experts, that finding suggests that the animals may have been infected and may have transmitted the virus to humans.
With vast amounts of genetic information extracted from swabs from animal cages, carts and other surfaces on the Wuhan market in early 2020, genetic data has been the focus of restless anticipation among virus experts since learning about it a year ago. in an article by Chinese scientists.
A French biologist discovered the genetic sequences in the database last week, and she and a team of colleagues began searching for clues to the origins of the pandemic.
That team has yet to publish a paper outlining the findings. But the researchers delivered an analysis of the material to a WHO advisory group studying the origins of Covid this week at a meeting that also included a presentation by Chinese researchers on the same data.
The analysis seemed to clash with earlier claims by Chinese scientists that samples taken at the market that tested positive for the coronavirus had been transported only by sick people, said Sarah Cobey, an epidemiologist and evolutionary biologist at the University of Chicago who was not involved. in the last analysis.
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“It’s just very unlikely to see that much animal DNA, especially raccoon dog DNA, mixed in with viral samples, if it’s just mostly human contamination,” Dr. Cobey said.
Questions remain about how the samples were collected, what exactly they contained, and why the evidence had disappeared. In light of the ambiguities, many scientists reacted cautiously, saying it was difficult to assess the research without seeing a full report.
The idea that a lab accident could have accidentally triggered the pandemic has come to the fore of renewed interest in recent weeks, thanks in part to a new Department of Energy intelligence assessment and hearings led by the new Republican leadership. of the camera.
But several virus experts not involved in the latest analysis said what was known about swabs collected from the market supported the case that animals sold there had caused the pandemic.
“This is exactly what you would expect if the virus emerged from an intermediate host or from multiple intermediates on the market,” said Dr. Cobey. “I think ecologically, this is close to a closed case.”
Dr. Cobey was one of 18 scientists who signed an influential letter in the journal Science in May 2021 urging serious consideration of a scenario in which the virus could have spilled out of a laboratory in Wuhan.
On Friday, he said that laboratory leaks continued to present enormous risks and that more oversight of the investigation of dangerous pathogens was needed. But Dr Cobey added that an accumulation of evidence, related to the clustering of human cases around the Wuhan market, the genetic diversity of the viruses there, and now the raccoon dog data, strengthened the case for the origin of the market.
The new genetic data does not appear to prove that a raccoon dog was infected with the coronavirus. Even if it had been, there would still be a chance that another animal could have transmitted that virus to people, or even that someone infected with the virus could have transmitted it to a raccoon dog.
Some scientists emphasized those points Friday, saying the new genetic data did not appreciably change the discussion about the origins of the pandemic.
“We know that it is a promiscuous virus that infects a lot of species,” said David Fisman, an epidemiologist at the University of Toronto, who also signed the May 2021 letter in Science.
Chinese scientists had launched a study in February 2022 looking at the market samples. Some scientists speculated that the Chinese researchers may have published the data in January because they were asked to make it available as part of a review of their study by a scientific journal.
The Chinese study suggested that the samples that tested positive for the virus came from infected people, rather than from animals sold on the market. That fits with a narrative long promulgated by Chinese officials: that the virus arose not just from outside the market, but also from outside the country.
But the Chinese report had left clues that the viral material on the market had been mixed with genetic material from animals. And the scientists said the new analysis by the international team illustrates an even stronger link to animals.
“Scientifically, it doesn’t prove that raccoon dogs were the source, but it certainly smells like infected raccoon dogs in the marketplace,” said Jeremy Kamil, a virologist at the Louisiana State University Health Sciences Center in Shreveport.
He added: “It raises more questions about what the Chinese government really knows.”
The scientists cautioned that it was not clear whether the genetic material of the virus and the raccoon dogs had been deposited at the same time.
Depending on the stability of the genetic material of the virus and the animals, said Michael Imperiale, a virologist at the University of Michigan, “they could have been deposited there at potentially very different times.”
Still, Dr. Arturo Casadevall, an immunologist at the Johns Hopkins Bloomberg School of Public Health and co-author of a recent study with Dr. Imperiale examining the origin of the coronavirus, said linking animal and viral material, however, was not possible. added to the evidence of a natural spill event.
“I would say that it strengthens the zoonotic idea,” he said, “meaning the idea that it came from an animal on the market.”
In the absence of the actual animal that first transmitted the virus to people, Dr. Casadevall said, assessing the origins of an outbreak would always involve weighing the odds. In this case, the animals sold on the market were recalled before researchers began taking samples in early 2020, making it impossible to find a culprit.
Tim Stearns, dean of graduate and graduate studies at Rockefeller University in New York, called the latest finding “an interesting piece of the puzzle,” though he said it “is not definitive in itself and highlights the need for further research.” thorough investigation.”
For all the missing items, some scientists said the new findings highlighted the amount of information scientists were able to piece together about the early days of the pandemic, including the addresses of the first patients and market sequence data.
Theodora Hatziioannou, a virologist at Rockefeller University, said it was critical that the raw data be published. But, she said, “I think the evidence is overwhelming right now for a market origin.”
And the most recent data, he said, “makes it even more unlikely that this started somewhere else.”
Felicia Goodrum, an immunobiologist at the University of Arizona, said finding the virus in a real animal would be the strongest evidence of a commercial origin. But finding virus and animal material on the same swab was close.
“For me,” he said, “this is the best option.”