A researcher in France has identified previously undisclosed genetic data from the Huanan Seafood Market in Wuhan, China, that she and colleagues say support the theory that coronavirus-infected animals there triggered the COVID-19 pandemic. Science has more.
Several of the researchers presented their findings on Tuesday to the Scientific Advisory Group for the Origins of Novel Pathogens (SAGO), an expert group convened last year by the World Health Organisation.
“The data does point even further to a market origin,” says Kristian Andersen, an evolutionary biologist at Scripps Research who attended the meeting and is one of the scientists analysing the new data. If so, the findings weaken the view of a vocal minority that a virology lab in Wuhan was the likely origin of SARS-CoV-2, perhaps when the coronavirus infected a lab worker, who spread it further.
Florence Débarre, a theoretician who specialises in evolutionary biology and works at the French National Centre for Scientific Research, unearthed the data, which consists of genetic sequences posted in GISAID, a virology database, by Chinese researchers. The Chinese team had collected environmental samples from the Huanan Seafood Market, which was connected to a cluster of early COVID-19 cases and despite its name also sold a variety of mammals for food. Since Débarre spotted the sequences, GISAID has removed them, noting that this was at the request of the submitter.
Given that the mystery of SARS-CoV-2’s origin has been a matter of intense global interest and divisive debate, the data’s discovery and subsequent disappearance will certainly raise questions about why the Chinese team — which includes the former head of China’s Center for Disease Control and Prevention (CDC), George Gao — did not make the sequences public earlier. Contacted by Science, Gao said the sequences are “[n]othing new. It had been known there was illegal animal dealing and this is why the market was immediately shut down”.
But Andersen and his colleagues hope Gao’s team will now make the sequences widely available. “We have urged China CDC and our colleagues there to release this data as soon as possible,” he says.
Gao’s team used swabs to collect environmental samples from many of the stalls of the Huanan market between January 1st, the day it was shut down, and March 2nd 2020. The group reported last year that some of the samples that tested positive for SARS-CoV-2 also had human genetic material, but no DNA from other animals. The team concluded in a preprint posted on Research Square on February 25th 2022, that this “highly suggests” humans brought the virus to the market — a finding that Gao and co-authors wrote meant the marketplace was not the origin of the pandemic but simply amplified early spread of SARS-CoV-2.
To some Chinese researchers and officials, that scenario suggested the virus originated outside China and somehow found its way to Wuhan. To lab leak supporters, it implied the pandemic might have started at the Wuhan lab.
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Lower down, the article notes that Andersen adds he does not expect the new data to convince everyone that the virus originated at the market as “he suspects some people may interpret the new information to mean simply that humans infected with SARS-CoV-2 transmitted the virus to the animals at the market”.
We’ll have to wait to see the detail when it’s published, but from these reports it sounds like it’s pretty inconclusive. If it did corroborate the wet market theory it would be very surprising at this point, as the evidence that the virus did not originate there is now very strong. It includes not only the fact that no animal reservoirs of the virus were found there but that many of the early sequenced cases had no connection to the market, that the cases at the market were all (except one) of the later lineage B, plus all the evidence that the virus is engineered including being immediately well-adapted to human transmission with a unique (in SARS-like viruses) furin cleavage site in its receptor binding domain. Traces of the virus have also been found in Brazil, England and the U.S. during November 2019, strongly challenging the idea that the December wet market outbreak was the point of origin.
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