BEIJING (AP) — Genetic material collected at a Chinese market near where the first human cases of COVID-19 were identified shows raccoon dog DNA mixing with the virus, giving evidence to the theory adds that the virus comes from animals and not from a lab. say international experts.
“These data do not provide a definitive answer as to how the pandemic began, but each and every piece of data is important in moving us closer to that answer,” World Health Organization director-general Tedros Adhanom Ghebreyesus said on Friday.
How the corona virus came about remains unclear. Many scientists believe it most likely jumped from animals to humans at a wildlife market in Wuhan, China, like many other viruses in the past. But Wuhan is home to several labs involved in coronavirus collection and study, fueling theories scientists say are plausible that the virus may have leaked from one.
The new findings do not resolve the issue, 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, saying in a news conference that “this data could and should have been shared three years ago.”
The samples were collected in early 2020 from surfaces at the Huanan Seafood Market in Wuhan, where the first human cases of COVID-19 were found in late 2019.
Tedros said the genetic sequences were recently uploaded to the world’s largest public virus database by scientists at the China Center for Disease Control and Prevention.
They were then removed, but not before a French biologist accidentally discovered the information and shared it with a group of scientists outside of China studying the origins of the coronavirus.
The data shows some of the COVID-positive samples taken from a pen known to be involved in the wildlife trade also contained raccoon dog genes, suggesting 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 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 after that and take environmental samples of a zoonotic spillover event … that’s basically what you would expect.”
The dogs, named for their raccoon-like faces, are often bred for their fur and sold for meat at animal markets across China.
Ray Yip, an epidemiologist and founding member of the US Centers for Disease Control’s China office, said the findings are significant, although not definitive.
“The market environmental sampling data released by China CDC is by far the strongest evidence supporting animal origin,” Yip told the AP in an email. He was not connected to the new analysis.
WHO’s chief technical officer for COVID-19, Maria Van Kerkhove, warned that the analysis had not found the virus in any animals, nor had it found any clear evidence that animals had infected humans.
“What this provides are clues to help us understand what might have happened,” she said. The international group also told WHO it found DNA from other animals, as well as raccoon dogs, in the samples from the fish market, 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 such as pangolins, ferrets or raccoon dogs.
Efforts to determine the origins of the COVID-19 pandemic have been complicated by factors such as the massive spike in human infections over the first two years of the pandemic and an increasingly acrimonious political strife.
It took virus experts more than a dozen years to determine 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 wildlife infected with the coronavirus in the market. But it’s also possible that humans introduced the virus and infected the raccoon dogs, or that infected humans simply accidentally left traces of the virus around the animals.
After scientists from the group contacted the China CDC, they said the sequences had been removed from the global virus database. Researchers are puzzled as to why the data on the samples collected over three years ago wasn’t released earlier. Tedros has asked China to share more of its COVID-19 research data.
Gao Fu, the former head of China’s CDC and lead writer for the Chinese newspaper, did not immediately respond to an Associated Press email asking for comment. But he told Science magazine the sequences were “nothing new. It was known that there was illegal animal trade and therefore the market was closed immediately.”
Goldstein said his group presented their findings this week to a WHO advisory panel studying the origins of COVID-19.
Michael Imperiale of the University of Michigan, a microbiology and immunology expert who wasn’t involved in the data analysis, said that finding a sample with sequences of the virus and a raccoon dog “puts the virus and the dog in very close proximity.” But it doesn’t necessarily mean the dog was infected with the virus; it just says they were in the same very small area.”
He said that the bulk of the scientific evidence at this point supports natural exposure in the market, citing research published last summer that showed the market was likely the early epicenter of the scourge, and concluded that the virus was twice transmitted from animals to humans . “What’s the probability that there were two different lab leaks?” he asked.
Mark Woolhouse, an infectious disease expert at the University of Edinburgh, said it was crucial to see how the raccoon dogs’ genetic sequences matched what is known about the historical evolution of the COVID-19 virus. If the dogs are shown to have COVID and these viruses are found to have earlier origins than those that infected humans, “that’s probably as good evidence as we can expect that this is a spillover event in the market.” was.”
After a weeks-long visit to China to investigate the origins of the pandemic, the WHO released a report in 2021 concluding that COVID-19 most likely jumped from animals to humans, and the possibility of a laboratory origin as “extremely unlikely”.
But the UN health agency backtracked the following year, saying “key data” was still missing. And Tedros has said that all hypotheses remain on the table.
China’s CDC scientists, who previously analyzed samples from the Huanan market, released a preprint paper in February advising that humans brought the virus to the market, not animals, implying that the virus originated elsewhere. Your 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 others in the US intelligence community disagree, believing it’s more likely it came from animals first.
Experts say the true origin of the pandemic may not be known for many years — if at all.
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Cheng reported from London. AP science writer Laura Ungar contributed to this story from Louisville.
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Dake Kang and Maria Cheng, The Associated Press
