A Chinese research team has analysed biological evidence from the market where Covid-19 is believed to have originated more than three years ago. The study, which is peer-reviewed, shows that the virus was associated with wild animals sold in the Huanan seafood and wildlife market. This could help investigate how the coronavirus outbreak started. The swabs that were positive for the virus also had genetic material from wild animals. Some scientists think this supports the idea that the disease came from an animal to a human. But others say the findings are not conclusive and wonder why the genetic data of the samples was not released earlier. Another possibility is that the virus escaped from a Wuhan lab by accident.
The journal Nature published the new analysis that other scientists have verified. It reveals more details about the samples taken from the market, such as the stalls, surfaces, cages and machines. The paper by the Chinese research team showed that some samples from the wildlife areas had the virus. They also found that raccoon dogs and other animals that can catch the virus were alive in those places. But the Chinese researchers say that their findings are not enough to confirm how the outbreak began.
“These environmental samples cannot prove that the animals were infected,” the paper explains.
The possibility remains, it adds, that the virus was brought into the market by an infected person, rather than an animal.
Prof David Robertson, from the University of Glasgow, a virologist who has been involved in the genetic investigation into the origin of SARS-CoV-2 since it emerged in 2020 advised.
“The most important thing is that this very important dataset is now published and available for others to work on.”
But he added that the contents of the samples were “compelling evidence that animals there were probably infected with the virus”.
“It’s the whole body of evidence that’s important,” he said.
“When you bring this together with the fact that the early Covid-19 cases in Wuhan are linked to the market, it’s strong evidence that this is where a spillover from an animal in the market occurred.”
The published findings come amid signs that the lab leak theory is gaining ground among authorities in the US.
The Chinese government has strenuously denied suggestions that the virus originated in a scientific facility, but the FBI said it now believes that scenario is the “most likely”, as does the US Department of Energy.
Various US departments and agencies have investigated the mystery and produced differing conclusions, but on 1 March the FBI’s director accused Beijing of “doing its best to try to thwart and obfuscate”, and disclosed the bureau had been convinced of the lab leak theory “for quite some time now”.
The FBI has not made their findings public, which has frustrated some scientists.