An international team of virologists said Thursday they had discovered genetic data linking the coronavirus to raccoon dogs from a market in Wuhan, China, adding to evidence that the worst pandemic in a century may have been ignited. An infected animal that is handled through the illegal wildlife trade.
The genetic data was taken from swabs taken from the Huanan Seafood Wholesale Market and surrounding areas since January 2020, shortly after Chinese authorities closed the market due to suspicions that it was linked to a new virus outbreak. By then, the animals had been removed, but the researchers scrubbed the walls, floors, metal cages and carts often used to transport the animals.
In the samples that came back positive for the coronavirus, the international research team found genetic material belonging to animals, including large amounts matching a raccoon dog, said three scientists involved in the analysis.
The combination of virus and genetic material from an animal does not prove that a raccoon was infected by a dog. And even if a raccoon dog is infected, it’s not clear that the animal transmitted the virus to people. Another animal may have transmitted the virus to people, or someone infected with the virus may have transmitted the virus to a raccoon dog.
But the analysis showed raccoon dogs — fluffy animals related to foxes and capable of spreading the coronavirus — deposited genetic signatures in the same place where genetic material from the virus remains, the three scientists said. That evidence, they said, was consistent with a scenario in which the virus spread from a wild animal to humans.
A report containing full details of the findings of the International Study Group is yet to be published. Their analysis was reported first Atlantic.
While not resolving the question of how the epidemic began, the new evidence is sure to provide a shock to the debate about the origin of the epidemic.
In recent weeks, the lab leak theory that the coronavirus emerged from a research lab in Wuhan has gained traction thanks to a new intelligence assessment by the US Department of Energy and investigations led by new Republican leadership.
But genetic data from the market provide some more concrete evidence of how the virus might have spread from wild animals outside the lab to people. It also suggests that Chinese scientists have provided an incomplete account of evidence that could fill in the details of how the virus spread in the Huanan market.
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Jeremy Kamil, a virologist at Louisiana State University Health Sciences Center Shreveport, who was not involved in the study, said the findings show that “samples from markets of early Covid origin were contaminated with DNA reads from wild animals.”
Dr Kamil said there was little conclusive evidence that an infected animal had triggered the epidemic. But, he said, “it really draws attention to the illegal animal trade in an intimate way.”
Chinese scientists A study February 2022 sees the same market patterns. That study reported samples positive for the coronavirus, but said the virus came from victims shopping or working at the market, not from animals sold there.
At one point, the same researchers, including some affiliated with the Chinese Centers for Disease Control and Prevention, released raw data from swabs on the market to GISAID, an international repository of genome sequences for viruses. (Efforts to reach the Chinese scientists by phone Thursday were unsuccessful.)
On March 4, Florence Debare, an evolutionary biologist at the French National Center for Scientific Research, was searching the database for information related to the Huanan market when she noticed in an interview that more footage than usual appeared. At first Dr. was confused as to whether they contained new data. Debare put them away, logging back in last week to discover they had a collection of raw data.
Virus experts have been eagerly awaiting that raw sequence data from the market since learning of its existence in a Chinese report from February 2022. Dr. Debare said he alerted other scientists, including the leaders of the group that published the latest set of studies. Year indicating origin of the market.
An international team — including Michael Worobe, an evolutionary biologist at the University of Arizona; Christian Anderson, a virologist at Scripps Research Institute in California; and Edward Holmes, a biologist at the University of Sydney — began mining the new genetic data last week.
One model in particular caught their attention. Scientists involved in the analysis said it was taken from a cart attached to a particular stall in the Huanan market visited by Dr Holmes in 2014. That stall, Dr. Holmes found, had raccoon dogs caged on top of a separate cage that housed the birds, an ideal environment for new viruses to spread.
A swab taken from a cart in early 2020 contained genetic material from the virus and a raccoon dog, the research team found.
“In one of these samples, we were able to find relatively quickly that there was a lot of raccoon dog nucleic acid along with viral nucleic acid,” said Stephen Goldstein, a virologist at the University of Utah. A 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 had uploaded the files with an offer to cooperate, according to the rules of the online repository, scientists involved in the new analysis said. After that, the footage disappeared from GISAID.
It is not known who removed them and why.
Dr. Debare said the research team is looking for more data, including some from market samples that are not always made public. “The key is to have more data,” he said.
Scientists involved in the study said some of the samples also contained genetic material from other animals and humans. Angela Rasmussen, a virologist at the Institute of Vaccines and Infectious Diseases at the University of Saskatchewan in Canada, said human genetic material should be expected because people shop and work there. Connected to the market.
Dr. Goldstein also cautioned, “We don’t have an infected animal, and we can’t definitively prove that there was an infected animal in that stall.” The genetic material of the virus is sufficiently stable that it is not clear when it was deposited on the market, he said. He said the team was still analyzing the data and did not intend to make its analysis public before releasing the report.
“But,” he said, “the animals in the market were not sampled at the time, and it is good to hope that we can get them.”