The protracted and rancorous debate over the origin of the covid pandemic has added a small but potentially significant data point: A sample taken in a Wuhan market in early 2020 showed genetic traces of both the coronavirus and a raccoon dog, according to scientists who have analyzed newly obtained data from China.
Like so many elements of the mystery, the new data, first reported by The Atlantic, falls short of proving how, where and when people first became infected with the virus. But it boosts the theory that the pandemic started through natural spillover from animals rather than emerging from a laboratory, a theory favored by some researchers.
The new evidence comes via swabs taken in animal stalls at the Huanan Seafood Market in Wuhan. Investigators collected them in early 2020 after the market had been closed and all the animals removed. One swab contained a mixture of genetic material that included a large amount from a raccoon dog along with traces from the coronavirus, said Stephen Goldstein, a virologist at the University of Utah who was part of the team that analyzed the data.
The data come from Chinese scientists who have submitted a paper to a scientific journal that has not yet been published, Goldstein said. The scientists involved in the new analysis, which has not been peer-reviewed or published in a journal, said they plan to post their work online within the next couple of days.
“We can’t definitively prove that there were infected raccoon dogs who were the first source of the virus going into humans,” Goldstein said, “but it is highly suggestive of that.”
Other animals that were probably sold in the market are also capable of being infected with SARS-CoV-2, the virus that causes covid-19. But the new evidence “moves raccoon dogs to the top of the list of animals that started the pandemic,” Robert Garry, a virologist at Tulane University who took part in the new analysis and has long favored the market theory, said Friday in an email.
“It’s just one more brick on this massive wall of evidence that all fits together,” Worobey said. “If it weren’t so politicized, it’s one of the clearest sets of evidence for how a pandemic emerged that we’ve ever had.”
But David A. Relman, a professor of microbiology and immunology at Stanford University who has said both origin scenarios are plausible, called the new data “very inconclusive” in an email. “Frankly, the breathlessness and alacrity with which stories like this one are promoted, in the face of very incomplete and confusing ‘data’, leaves me frustrated and concerned,” he said.
The virus origin debate has become heavily politicized, and this latest data point, coming from scientists who have long argued for a market origin, is unlikely to shift the views of those who favor the lab leak theory.