Covid origins data links pandemic to raccoon dogs in Wuhan market

International scientists who examined previously unavailable genetic data from samples taken from a market near where the first human cases of Covid-19 were detected in China said they found suggestions that the pandemic originated animals, not a laboratory.

Other experts have yet to verify their analysis, nor has it appeared in a peer-reviewed journal so far. How the coronavirus started making people sick remains unclear.

“These data do not provide a definitive answer to how the pandemic started, but every piece of data is important in bringing us closer to that answer,” WHO Director-General Tedros Adhanom Ghebreyesus said during a briefing. a press briefing on Friday.

He also criticized China for not sharing the genetic information sooner, adding that “this data could and should have been shared three years ago.”

The samples were taken from surfaces in the Huanan seafood market in Wuhan after the first human cases of Covid-19 were discovered in late 2019.

Tedros said the genetic sequences were uploaded to the world’s largest public virus database in late January by scientists from the Chinese Center for Disease Control and Prevention; the data has since been deleted from the database.

A French biologist spotted the information by chance browsing through the database and shared it with a group of scientists based outside China investigating the origins of the coronavirus.

Genetic sequencing data showed that some of the samples, which were known to be positive for the coronavirus, also contained genetic material from raccoon dogs, indicating that the animals may have been infected with the virus, the scientists said. Their analysis was first reported in The Atlantic.

“There’s a good chance that the animals that deposited this DNA also deposited the virus,” said Stephen Goldstein, a virologist at the University of Utah who helped analyze the data. “If you were to go do environmental sampling following a zoonotic spread event…this is basically exactly what you would expect to find.”

Ray Yip, an epidemiologist and founding member of the US Centers for Disease Control’s office in China, said while the new findings weren’t definitive, they were important.

“Market environmental sampling data released by China CDC is by far the strongest evidence to support animal origins,” Yip told the AP in an email. It was not linked to the new analysis.

Scientists have been searching for the origins of the Covid-19 pandemic since the virus emerged, but that search has been complicated by factors including the massive spike in human infections in the first two years of the pandemic and a political dispute. more and more bitter.

It took more than a dozen years for virus experts to identify the animal origin of SARS, a related virus.

The researchers say their analysis is the first solid indication that there may have been wild animals infected with the coronavirus on the market. Some of the samples containing raccoon dog DNA were taken from a booth that tested positive for Covid-19 and was known to be involved in the wildlife trade, Goldstein said.

But it’s also possible that humans first brought the virus to market and infected raccoon dogs, or that infected humans left traces of the virus near the animals.

After the group’s scientists contacted the Chinese CDC, they say, the sequences were extracted from the Global Virus Database. Researchers are puzzled as to why data on samples collected more than three years ago has not been made public sooner.

Earlier this week, some of the scientists presented their findings to an advisory group the World Health Organization appointed to investigate the origins of Covid, Goldstein confirmed.

Mark Woolhouse, an infectious disease expert at the University of Edinburgh, said it will be crucial to see how the genetic sequences of raccoon dogs match up with what is known about the historical evolution of the Covid-19 virus. .

He said that while the analysis shows that animal viruses have origins that predate those that infected people, “that’s probably the best evidence we can expect to get that this was an event. overflow in the market”.

After a week-long visit to China to study the origins of the pandemic, the WHO published a report in 2021 concluding that Covid most likely jumped to humans from animals, ruling out the possibility of an origin of laboratory as “extremely unlikely”.

But the UN health agency backtracked the following year, saying “key pieces of data” were still missing.

In recent months, WHO Director Tedros has said all hypotheses remain on the table, while he and senior officials have pleaded with China to share more data on their Covid-19 research.

The Chinese CDC scientists who previously analyzed the samples published a preprint article in February. Their analysis suggested that humans brought the virus to market, not animals, implying that the virus originated elsewhere.

The article does not mention that animal genetic material was found in samples that tested positive for Covid-19, and the authors did not upload the raw data until March. Gao Fu, the former head of China’s CDC and lead author of the article, did not immediately respond to an email seeking comment.

Wuhan, the Chinese city where Covid-19 was first detected, is home to several laboratories involved in collecting and studying coronaviruses, fueling theories that the virus may have leaked from one.

In February, the Wall Street Journal reported that the US Department of Energy had assessed “with low confidence” that the virus had leaked from a lab. But other members of the US intelligence community disagree, believing it is more likely that it came from animals first. Experts say the true origin of the pandemic may not be known for many years – if ever.