Covid-19 investigation
Previously unseen genome samples suggest animals in the Huanan market were a potential source
Newly released data early in the Covid-19 pandemic has provided crucial insight into the origins of the outbreak, suggesting that Covid-infected animals were present at a Wuhan market and could have been a “potential source of human infection”.
A pre-printed report Monday by a team of international researchers fleshed out analysis of previously unseen genome samples collected by Chinese scientists at Wuhan’s Huanan Market in the early days of the pandemic.
Originally leaked last week after a meeting of the World Health Organization (WHO) committee investigating the origins of the outbreak, it appeared to show a likelihood that raccoon dogs and other species were present and potentially infected in the market.
“This adds to the evidence identifying Huanan market as a spillover site of Sars-CoV-2 and an epicenter of the Covid-19 pandemic,” the report said.
The latest research into the origins of Covid-19 came as US President Joe Biden signed legislation mandating the release of intelligence materials on possible 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 lab may have been linked to the outbreak.
“We need to get to the bottom of the origins of Covid-19 … including possible links to the Wuhan Institute of Virology,” Biden said in a statement. “In implementing this legislation, my government will release and share as much of this information as possible.”
Biden’s move came as newly updated genetic material from Wuhan’s Huanan market was briefly released to a globally accessible database by the China Center for Disease Control and Prevention (CDC). China’s CDC presented these findings at a meeting of WHO experts researching the origins of the virus.
The new research examined genomic sequences from the newly released material collected at the Wuhan market.
The research examined samples including swabs from stalls at the market, sewage systems and 18 specific animals – both frozen and live – around the site, including strays at the market.
What is notable about the new research is that it identifies high levels of DNA from several species that were not identified as tested when the original sampling was carried out.
These include raccoon dogs, which it is speculated were present in the market before they were cleared as part of Chinese health officials’ immediate intervention early in the outbreak.
Although some of the material was leaked last week, the new report adds more details on other animals on the market and shows that some of the Sars-CoV-2 positive environmental samples contained more animal than human genetic material. what the researchers said matched the infected animals.
The release of the new research followed a statement two days ago by the WHO Scientific Advisory Group on the Origins of Novel Pathogens, which assessed the importance of what they had shown.
“The presentations by China CDC and invited international researchers showed that there was newly available data from the seafood wholesale market in Huanan,” it said.
“Analysis of this data indicates that some samples contained human DNA in addition to Sars-CoV-2 sequences, as well as mitochondrial DNA from multiple animal species, including some known to be susceptible to Sars-CoV-2.
“This included, among other things, DNA from wild raccoon dogs, Malaysian porcupines and bamboo rats in SarsS-CoV-2-positive environmental samples.
“While this does not provide conclusive evidence as to the intermediate host or the origin of the virus, the data provides further evidence of the presence of susceptible animals in the market that may have been a source of human infection.”
The new material is significant because the search for an intermediate animal host has been one of the two focuses of investigations into Covid’s origins, alongside the laboratory leak theory. However, the scientific consensus on the outbreak is leaning towards the theory that it was most likely zoonotic in origin and jumped from an animal to humans, as has happened with other similar viruses.
The release of the new data – amid long-standing and well-articulated concerns about China’s transparency regarding its own research on the outbreak – leaves many questions unanswered, not the least of which is why it has taken so long for the genetic sequences to surface.
“The data points 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 examined the samples, told Science last week.
Like the new data, the Biden administration’s move to release US intelligence on the source of the outbreak is unlikely to be the last word in the scientific debate or in the highly polarized political debate over its origins.
While the disclosure that the US Department of Energy had assessed a lab leak as the source has received considerable attention – albeit with low confidence, supporting a similar FBI assessment – a majority of US agencies are inclined to dismiss the outbreak as a natural event regard.
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