New Research Identifies Wuhan Animal Market As Most Likely Covid Source

The Chinese have tried to deflect attention from their country's role in spreading the Covid virus. And right wingers in the US have tried to blame intentional Chinese bio-warfare research to deflect blame from the Trump administration.

But new research from evolutionary biology - and reported in the Wall Street Journal, one of those media fanning the bio-warfare flames - suggest that animals sold from the Huanan seafood market in Wuhan were the origin of the pandemic. JL  

Betsy McKay reports in the Wall Street Journal:

A scientist known for investigating viral origins has reconstructed the first known weeks of the Covid-19 pandemic, adding to a growing body of evidence that the virus behind it jumped from infected animals to humans rather than emerging from laboratory research.  A paper published Thursday concludes a wholesale seafood market in Wuhan, China, where live mammals were sold is very likely to be the site of the origin of the pandemic. Most of the known Covid-19 cases in December 2019 had a direct or indirect link to the Huanan market.

A scientist known for investigating viral origins has reconstructed the first known weeks of the Covid-19 pandemic, adding to a growing body of evidence that the virus behind it jumped from infected animals to humans rather than emerging from laboratory research.

In a paper published Thursday in the academic journal Science, Michael Worobey concludes a wholesale seafood market in Wuhan, China, where live mammals were sold is very likely to be the site of the origin of the pandemic.

The precise role of the Huanan market in the pandemic has been debated by scientists. Dr. Worobey, an evolutionary biologist at the University of Arizona who previously unearthed clues about the origins of the 1918 pandemic flu and HIV, showed that most of the known Covid-19 cases in December 2019 had a direct or indirect link to the Huanan market. These infected people worked at the market, visited it, had contact with someone who was there or lived nearby, he found by piecing together genetic data, reports and accounts of early patients.

Among his conclusions are that a man believed to be the first case actually got sick later, when the virus was likely spreading in the community. The man’s case has been used to question the importance of the market because he hadn’t visited it.

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The reconstruction suggests that early transmission of the virus was tied to the market, Dr. Worobey said. Most who were at the market and got ill visited a section where live raccoon dogs, which carry coronaviruses, were sold, which “provides strong evidence of a live-animal market origin of the pandemic,” he wrote.

“You can no longer just dismiss the Huanan market link,” Dr. Worobey said.

Dr. Worobey’s work adds to mounting evidence of a natural, or so-called zoonotic, origin of SARS-CoV-2, the virus that causes Covid-19. While many virologists and others who study epidemics say a laboratory accident in Wuhan can’t be ruled out, they believe it’s far more likely that the new virus’s origin occurred in nature.

SARS-CoV-2 appears to have come from a bat, then infected another animal and made some crucial changes in its genetic makeup and jumped to humans, recent research suggests. That would follow the pattern of other new viruses that virologists have traced to “spillovers” from animals to humans.

“My feeling has always been that the virus emerging from an animal source was more likely and my confidence in that is growing” due to Dr. Worobey’s article and other recent research, said Stephen Goldstein, an evolutionary virologist at the University of Utah.

For his analysis, Dr. Worobey, said, “I just trawled through anything I could find,” including the World Health Organization-led team’s report, genomic data, local media reports, and announcements from Chinese officials that had been taken down but stored on an internet archive.

He found that 10 of 19 early patients evaluated by doctors at hospitals in Wuhan worked at the Huanan market or had been there. A 41-year-old accountant believed to have become sick Dec. 8—making him officially the first known case—actually was ill from a dental problem then and developed Covid-19 symptoms on Dec. 16 instead, Dr. Worobey wrote. That would mean he could have caught the virus from someone in the broader community, since he didn’t visit the market, Dr. Worobey said.

Dr. Worobey said he learned of the accountant’s dental problem from information in a video from China sent to him by a reviewer of his article, and other details were corroborated by hospital records and a scientific paper.

The first known cases are almost certainly not the first people to have been infected with the virus, Dr. Worobey said. Finding the precise origin of the pandemic will require more information about people who were sick earlier and more data from China, said Jesse Bloom, a virologist at the Fred Hutchinson Cancer Research Center in Seattle. “In my view, tracing the origin of SARS-CoV-2 through the known early patients is an instance where the data aren’t sufficient to provide an answer,” he said.

Finding the origin of an epidemic can take years; scientists have yet to pinpoint the precise source of the virus that caused the epidemic of severe acute respiratory syndrome, or SARS, in 2002 and 2003.

Still, they have made a lot of progress in a short time. “We know more about SARS-CoV-2 and how it got into the human population than these other viruses,” including the first SARS, said Robert Garry, a virologist at Tulane University School of Medicine who was an author of one of the first scientific papers concluding the virus had a natural origin.

Researchers at the Pasteur Institute, a French nonprofit, reported in September that they had found three coronaviruses in bats in caves in northern Laos, close to the Chinese border, that very closely resemble SARS-CoV-2 and can infect human cells. The portion of the bat viruses that attach to cells, called the receptor binding domain, differs from that portion of SARS-CoV-2 by only one or two amino acids, the researchers said. Their findings were reported on a preprint server, and are being reviewed for publication in a scientific journal.

One of the viruses, collected in 2020 and dubbed in their study “Banal-52,” is so close that it is “essentially the progenitor of SARS-CoV-2,” Dr. Garry said during a webinar this week hosted by the Global Virus Network, a coalition of virologists.

The discovery of these viruses undermines the hypothesis that SARS-CoV-2 was created or adapted in a laboratory, he said. The differences between these viruses and SARS-CoV-2 show that the latter circulated in another animal after bats, adapting other properties such as a furin cleavage site that made it more transmissible among humans, he said.

Guards protect the entrance as members of the World Health Organization team arrive at the Huanan market in Wuhan, China, in January 2021.

PHOTO: HECTOR RETAMAL/AGENCE FRANCE-PRESSE/GETTY IMAGES

The viruses in Laos and another close relative of SARS-CoV-2 found years ago in China, called RaTG13, support the idea that close ancestors of the pandemic pathogen probably came from a bat in southern China or northern Laos, said Dr. Bloom.

Dr. Bloom was among 18 scientists who signed a letter published in May calling for a deeper investigation into both the hypothesis that the pandemic resulted from a laboratory leak as well as from a spillover from infected animals to humans.

“It’s still unclear where the first infection happened and how the outbreak originated in Wuhan,” he said.

Dr. Worobey also signed the letter, he said, because he was concerned that the possibility of a laboratory accident wasn’t being taken seriously enough. U.S. intelligence agencies were unable to determine conclusively how the pandemic originated, after a 90-day assessment earlier this year, though they said the virus wasn’t developed as a biological weapon.

Experts in emerging pathogens have said the new virus could have spread to humans from an infected live animal or animals at the Huanan market, following a pattern seen with previous outbreaks of novel diseases. Scientists at the Chinese Center for Disease Control and Prevention backed that hypothesis in a January 2020 report that said “all current evidence points to wild animals sold illegally in the Huanan Seafood Wholesale Market.”

But subsequent reports cast doubt on the market because several early patients appeared to have no link to it, including the accountant. A March 2021 report by a World Health Organization-led team that included international and Chinese scientists said no evidence that live mammals were sold at the market in 2019 had been found.

In June, a team of researchers from China, the U.K. and Canada provided new evidence, though, of the opportunity for an animal spillover. They reported that more than 47,000 wild animals had been sold in Wuhan in the two and a half years before the first confirmed cluster of Covid-19 cases. The animals, often kept in crowded conditions where viruses can spread, and butchered on site, included at least four species that could carry SARS-CoV-2, including raccoon dogs.