International scientists who examined previously unavailable genetic data from samples collected at a market near where the first human cases of Covid-19 were discovered in China said they found suggestions that the epidemic originated from animals, rather than a laboratory.
Other experts have yet to verify their analysis, which has yet to appear in a peer-reviewed journal. How the coronavirus first started making people sick is still uncertain.
“This data does not provide a definitive answer to how the pandemic started, but every piece of data is important to bring us closer to that answer,” WHO Director-General Tedros Adhanom Ghebreyesus said at a news conference on Friday.
He also criticized China for not sharing genetic information earlier, adding that “this data could and should have been shared three years ago.”
The samples were collected from surfaces at the Huanan Seafood Market in Wuhan after the first human cases of Covid-19 were found in late 2019.
Tedros said the genetic sequences were uploaded to the world’s largest public virus database in late January by scientists at the Chinese Center for Disease Control and Prevention. The data has since been removed from the database.
A French biologist discovered the information by chance while searching the database and sharing it with a group of scientists based outside China and researching the origins of the coronavirus.
Genetic sequencing data showed that some 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, according to the scientists. Their analysis was first reported in The Atlantic.
“There’s a good chance that animals that deposited this DNA also deposited the virus,” said Stephen Goldstein, a University of Utah virologist who was involved in analyzing the data. “If you were to go and do environmental sampling in the aftermath of a zoonotic event…that’s exactly what you would expect to find.”
Ray Yip, an epidemiologist and founding member of the US Centers for Disease Control’s China office, said that while the new findings were not definitive, they were important.
“The market environmental sampling data published by China CDC is by far the strongest evidence in support of animal origins,” Yip told the AP in an email. It was not related to the new analysis.
Scientists have been searching for the origins of the Covid-19 pandemic since the virus first emerged, but that search has been complicated by factors including the huge spike in human infections in the first two years of the pandemic and an increasingly bitter political dispute.
It took more than a dozen years for virologists to pinpoint the animal origin of SARS, a related virus.
The researchers say their analysis is the first strong indication of possible wildlife infection with the coronavirus on the market. Some of the samples containing raccoon dog DNA were collected from a stall 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 scientists in the group contacted the CDC in China, they say, the sequences were pulled from the global virus database. The researchers are puzzled as to why the data on samples collected more than three years ago has not been made public.
Earlier this week, some scientists presented their findings to an advisory group tasked by the World Health Organization to investigate the origins of Covid, Goldstein confirmed.
Mark Woolhouse, an infectious disease expert at the University of Edinburgh, said it would be critical to see how genetic sequences from raccoon dogs match up with what is known about the historical evolution of the Covid-19 virus.
If the analysis shows that animal viruses have earlier origins than those that infected humans, he said, “this is likely to be as good evidence as we can expect this to be a spin-off in the market.”
After a weeks-long visit to China to study the origins of the pandemic, the World Health Organization released a report in 2021 concluding that Covid likely jumped to humans from animals, dismissing the possibility of a lab origin as “extremely unlikely”.
But the UN health agency backtracked the following year, saying “essential pieces of data” were still missing.
In recent months, WHO director Tedros said all hypotheses remained on the table, while he and top officials implored China to share more data on their research on Covid-19.
CDC scientists in China, who previously analyzed the samples, published a paper as a preliminary publication in February. Their analysis suggested that humans brought the virus to market, not animals, which means the virus originated elsewhere.
The paper did not say that animal genetic material was found in the samples that tested positive for Covid-19, and the authors did not upload the raw data until March. Gao Fu, former head of the Center for Disease Control and Prevention in China and lead author of the paper, 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 of them.
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 laboratory. But others in the American intelligence community disagree, and think it likely came first from animals. Experts say the true origin of the pandemic may not be known for many years – if it ever existed.
“Beer buff. Devoted pop culture scholar. Coffee ninja. Evil zombie fan. Organizer.”
A fire on a Philippine passenger ferry killed 28 people
The Vatican said Pope Francis will be hospitalized for several days with a respiratory infection
A huge scale dilemma for South Africa