Newly released data from early in the Covid-19 pandemic has offered a crucial insight into the outbreak’s origins, suggesting that Covid-infected animals were present at a market in Wuhan and could have been a “potential source of human infections”.
A pre-print report on Monday by a team of international researchers fleshed out analysis of previously unseen genomic samples collected by Chinese scientists at the Huanan market in Wuhan in the early days of the pandemic.
Initially leaked last week after a meeting of the World Health Organization (WHO) committee studying the origins of the outbreak, it appeared to show a likelihood that racoon dogs and other species were present at the market and potentially infected.
“This adds to the body of evidence identifying the Huanan market as the spillover location of Sars-CoV-2 and the epicentre of the Covid-19 pandemic,” said the report.
The latest research on Covid-19’s origins came as the US president, Joe Biden, signed into law a bill requiring the release of intelligence materials on potential links between the outbreak and a laboratory in the Chinese city of Wuhan. This follows reports that the US Department of Energy had assessed with “low confidence” that the laboratory may have been linked to the outbreak.
“We need to get to the bottom of Covid-19’s origins … including potential links to the Wuhan Institute of Virology,” Biden said in a statement. “In implementing this legislation, my administration will declassify and share as much of that information as possible.”
Biden’s move came as newly updated genetic material from Wuhan’s Huanan market from China’s Centre for Disease Control and Prevention (CDC) was briefly released on a globally accessible database. The Chinese CDC presented those findings at a meeting of WHO experts researching the virus’s origins.
The new research examined genomic sequences from the newly released material, which was collected at the Wuhan market.
The research looked at samples including swabs from stalls at the market, sewage systems and 18 specific to animals – both frozen carcasses and live – around the site, including strays around the market.
What is significant about the new research is that it identifies high levels of DNA from several species that were not identified as having been tested during the original sampling.
That includes racoon dogs, which it is speculated may have been present at the market before it was cleared early in the outbreak as part of the Chinese health authorities’ immediate intervention.
Although some of the material was leaked last week, the new report adds more detail about other animals present at the market, as well as showing that some of the Sars-CoV-2 positive environmental samples had more animal than human genetic material in them, which the researchers said was consistent with the animals being infected.
The release of the new research followed a statement from the WHO’s Scientific Advisory Group for the Origins of Novel Pathogens two days ago assessing the importance of what they had been shown.
“The presentations from China CDC and invited international researchers indicated that there were newly available data from the Huanan Seafood Wholesale Market,” it said.
“Analyses of these data suggest that, apart from Sars-CoV-2 sequences, some samples also contained human DNA, as well as mitochondrial DNA of several animal species, including some that are known to be susceptible to Sars-CoV-2.
“This included DNA from wild raccoon dogs, Malaysian porcupine and bamboo rats among others, in SarsS-CoV-2-positive environmental samples.
“Although this does not provide conclusive evidence as to the intermediate host or origins of the virus, the data provide further evidence of the presence of susceptible animals at the market that may have been a source of human infections.”
The new material is significant as a search for an intermediary animal host has been one of the twin focuses of investigations into Covid’s origins along with the lab leak theory. However, scientific consensus on the outbreak has leaned towards the theory that it was most likely zoonotic in origin, jumping from an animal to humans, as has occurred with other similar viruses.
The release of the new data – amid longstanding and well-aired concerns about China’s transparency around its own research into the outbreak – leaves many questions unanswered, not least why it has taken so long for the genetic sequences to emerge.
“The data does point even further to a market origin,” Kristian Andersen, an evolutionary biologist at Scripps Research, who attended the WHO meeting earlier this month and is one of the scientists who has examined the samples, told the journal Science last week.
Like the new data, the Biden administration move to declassify US intelligence on the source of the outbreak is unlikely to be the last word in either the scientific debate or the highly polarised political debate over the origins.
While considerable attention was paid to the disclosure that the US Department of Energy had assessed a lab leak as the source – albeit with low confidence, backing a similar assessment by the FBI – a majority of US agencies lean towards the outbreak being a natural event.