New data on COVID origins points to raccoon dogs in Chinese market
“These data don’t provide a definitive answer to how the pandemic started, but every piece of data is important in bringing us closer to that answer.”
BEIJING (AP) — Genetic material collected from a Chinese market near where the first human cases of COVID-19 were identified shows that raccoon dog DNA mixes with the virus, adding evidence to the theory according to which the virus came from animals, not a lab, say international experts.
“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,” World Health Organization Director-General Tedros Adhanom said on Friday. Ghebreyesus.
How the coronavirus emerged remains unclear. Many scientists believe it most likely jumped from animals to humans, like many other viruses have in the past, at a wildlife market in Wuhan, China. But Wuhan is home to several labs involved in collecting and studying coronaviruses, fueling theories that scientists are plausible that the virus could have leaked from one.
The new findings do not settle the matter, and they have not been formally reviewed by other experts or published in a peer-reviewed journal.
Tedros criticized China for not sharing the genetic information sooner, telling a press briefing that “this data could and should have been shared three years ago.”
The samples were taken from surfaces at the Huanan Seafood Market in early 2020 in Wuhan, where the first human cases of COVID-19 were discovered in late 2019.
Tedros said the genetic sequences were recently uploaded to the world’s largest public virus database by scientists from the Chinese Center for Disease Control and Prevention.
They were later taken down, but not before a French biologist spotted the information by chance and shared it with a group of scientists based outside China who are studying the origins of the coronavirus.
The data shows that some of the COVID-positive samples taken from a stall known to be involved in the wildlife trade also contained raccoon dog genes, indicating the animals may have been infected with the virus, the scientists say. Their analysis was first reported in Atlantic.
“There is 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.”
The dogs, named for their raccoon-like faces, are often bred for their fur and sold for meat in animal markets across China.
Ray Yip, epidemiologist and founding member of the US Centers for Disease Control’s office in China, said the results are significant, although not definitive.
“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.
WHO COVID-19 technical officer Maria Van Kerkhove warned that the analysis did not find the virus in any animals, nor did it find hard evidence that animals have infected humans.
“What this provides are clues to help us understand what may have happened,” she said. The international group also told the WHO that they had found DNA from other animals as well as raccoon dogs in the seafood market samples, she added.
The genetic code of the coronavirus is strikingly similar to that of bat coronaviruses, and many scientists suspect that COVID-19 jumped to humans either directly from a bat or via an intermediate animal like pangolins, ferrets or raccoon dogs.
Efforts to determine the origins of the COVID-19 pandemic have been complicated by factors including the massive 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 virus experts to identify the animal origin of SARS, a related virus.
Goldstein and his colleagues say their analysis is the first solid indication that there may have been wild animals infected with the coronavirus on the market. But it’s also possible that humans brought the virus into the marketplace and infected raccoon dogs, or that infected humans simply left traces of the virus near the animals.
After the group’s scientists contacted the Chinese CDC, they say, the footage was removed 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. Tedros pleaded with China to share more of its research data on COVID-19.
Gao Fu, the former head of China’s CDC and the Chinese newspaper’s lead author, did not immediately respond to an Associated Press email seeking comment. But he told Science magazine that the footage was “nothing new. It was known that there was an illegal trade in animals and that is why the market was immediately closed.
Goldstein said his group presented its findings this week to a WHO advisory group investigating the origins of COVID-19.
Michael Imperiale of the University of Michigan, a microbiology and immunology expert who was not involved in the data analysis, said the discovery of a sample with sequences of the virus and a raccoon dog ” places the virus and the dog very close”. But this does not necessarily mean that the dog has been infected with the virus; it just says they were in the same very small area.
He said the bulk of the scientific evidence at this stage supported natural exposure in the market, and pointed to research published last summer showing the market was likely the first epicenter of the plague and concluding that the virus has spread. spread from animals to people twice. . “What’s the chance there were two different lab leaks?” He asked.
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. . If dogs are shown to have COVID and these viruses turn out to have older origins than those that have infected people, “that’s probably the best evidence we can expect to get that it’s was a spillover event in the market”.
After a week-long visit to China to study the origins of the pandemic, the WHO released a report in 2021 concluding that COVID-19 most likely spread to humans from animals, ruling out the possibility of a laboratory origin as “extremely unlikely”.
But the UN health agency backtracked the following year, saying “key pieces of data” were still missing. And Tedros said all assumptions remain on the table.
Chinese CDC scientists who previously analyzed samples from the Huanan market published a preprint paper in February suggesting humans brought the virus to the market, not animals, implying the virus originated Besides. Their article did not mention that animal genes were found in the samples that tested positive.
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.
Cheng reported from London. AP Science Writer Laura Ungar contributed to this story from Louisville.
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