An international panel of virus experts said on Thursday they had found genetic data at a market in Wuhan, China that linked the coronavirus to raccoon dogs for sale there, adding evidence that the worst pandemic in a century could have been caused by the virus. an infected animal that has been sold through the illegal wildlife trade.

The genetic data was taken from swabs taken in and around the Huanan Seafood Wholesale Market starting in January 2020, shortly after Chinese authorities closed the market over suspicions that it was linked to a novel virus outbreak. By that time, the animals had already been removed, but the researchers were smearing walls, floors, metal cages and carts that were often used to transport animal cages.

In samples that tested positive for the coronavirus, an international research team found animal genetic material, including a large amount that matched a raccoon dog, three scientists involved in the analysis said.

Mixing the genetic material of the virus and the animal does not prove that the raccoon dog itself was infected. And even if a raccoon dog were infected, it would not be clear that the animal transmitted the virus to humans. Another animal could have transmitted the virus to humans, or someone infected with the virus could have passed the virus to a raccoon dog.

But the analysis did establish that raccoon dogs — furry animals that are related to foxes and known to be able to transmit the coronavirus — deposited genetic signatures in the same place where the genetic material from the virus was left, the three scientists said. This evidence, they say, is consistent with a scenario in which the virus entered humans from a wild animal.

A full report on the findings of the international research team has not yet been published. Their analysis was first reported Atlantic Ocean.

The new data is sure to revive the debate about the origin of the pandemic, even if it does not address the question of how it began.

In recent weeks, the so-called lab leak theory, which claims the coronavirus originated from a research lab in Wuhan, has gained traction thanks to a new intelligence assessment by the U.S. Department of Energy and hearings led by new Republican Chamber leadership.

But genetic data from the market offers some of the most tangible evidence of how the virus could have entered humans from wild animals outside the lab. It also suggests that Chinese scientists have given an incomplete account of the evidence that could fill in the details about how the virus spread in the Huanan market. .

Jeremy Kamil, a virologist at the Louisiana State University Health Sciences Center at Shreveport, who was not involved in the study, said the results showed “samples from the market that had early Covid lines were contaminated with wild animal DNA reads.”

Dr Kamil said he lacked conclusive evidence that an infected animal caused the pandemic. But, he says, “it really brings out the illegal animal trade in a personal way.”

Chinese scientists released study considering the same market samples in February 2022. This study reported that the samples were positive for coronavirus, but it was assumed that the virus came from infected people who shopped or worked at the market, and not from the animals that were sold there.

At some point, the same researchers, including those affiliated with the Chinese Centers for Disease Control and Prevention, posted raw swab data from the market to GISAID, the international repository for viral genetic sequences. (Attempts to contact Chinese scientists by phone on Thursday were unsuccessful.)

On March 4, Florence Debarre, an evolutionary biologist at the French National Center for Scientific Research, accidentally searched the database for information related to the Huanan market when, she said in an interview, she noticed that more sequences than usual were showing up. first about whether they contained new data, dr. DeBarr put them aside, only to log back in last week to find they had a lot of raw data stored in them.

Virus experts have been waiting for this raw sequence data from the market since they learned of its existence in a February 2022 Chinese report. Debarre said she alerted other scientists, including the leaders of a group that published a number of studies last year pointing to the market as the source.

An international team that included Michael Sparrow, an evolutionary biologist at the University of Arizona; Christian Andersen, virologist at the Scripps Research Institute in California; and Edward Holmes, a biologist at the University of Sydney, began collecting new genetic data last week.

One specimen in particular caught their attention. It was taken from a cart tied to a specific stall in the Huanan Market where Dr. S. Holmes visited in 2014, according to scientists involved in the analysis. This tent, doctor. Holmes found that raccoon dogs were kept in a cage on top of a separate cage with birds, and this is precisely the environment that facilitates the transmission of new viruses.

The research team found that a swab taken from a cart in early 2020 contained virus and raccoon dog genetic material.

“We were able to figure out relatively quickly that at least one of those samples had a lot of raccoon dog nucleic acid, along with virus nucleic acid,” said Steven Goldstein, a virologist at the University of Utah who worked on the study. new analysis. (Nucleic acids are the chemical building blocks that carry genetic information.)

After the international team stumbled upon the new data, they approached the Chinese researchers who uploaded the files to collaborate while respecting the rules of the online repository, the scientists involved in the new analysis said. After that, the sequences disappeared from GISAID.

It is not clear who removed them or why they were removed.

Dr. Debarre said the research team was looking for more data, including some of the market samples that have never been released to the public. “The important thing is that there is even more data,” she said.

Scientists involved in the analysis said some of the samples also contained genetic material from other animals and humans. Angela Rasmussen, a virologist with the Organization for Vaccines and Infectious Diseases at the University of Saskatchewan in Canada who worked on the analysis, said the human genetic material was to be expected given that people shopped and worked there and cases of Covid in humans were reported. were connected to the market.

Dr. Goldstein also warned that “we don’t have an infected animal, and we can’t prove for sure that there was an infected animal in that stall.” The genetic material of the virus is quite stable, he said, so it is not clear exactly when it entered the market. He said the team was still analyzing the data and that it had no intention of releasing its analysis prior to releasing the report.

“But,” he said, “given that the animals that were on the market were not selected at the time, this is the best we can hope for.”