“Scientifically, it doesn’t prove that raccoon dogs were the source, but it sure smells like infected raccoon dogs were at the market,” said Jeremy Kamil, a virologist at Louisiana State University Health Sciences Center Shreveport.
He added, “It raises more questions about what the Chinese government really knows.”
Scientists cautioned that it was not clear that the genetic material from the virus and from raccoon dogs had been deposited at the same time.
Depending on the stability of genetic material from the virus and the animals, said Michael Imperiale, a virologist at the University of Michigan, “they could have been deposited there at potentially widely different times.”
Still, Dr. Arturo Casadevall, an immunologist at the Johns Hopkins Bloomberg School of Public Health who co-authored a recent study with Dr. Imperiale examining the origin of the coronavirus, said that linking animal and viral material nevertheless added to the evidence of a natural spillover event.
“I would say it strengthens the zoonotic idea,” he said, “that is, the idea that it came from an animal at the market.”
In the absence of the actual animal that first spread the virus to people, Dr. Casadevall said, assessing the origins of an outbreak would always involve weighing probabilities. In this case, animals sold at the market were removed before researchers began taking samples in early 2020, making it impossible to find a culprit.
Tim Stearns, the dean of graduate and postgraduate studies at the Rockefeller University in New York, said that the latest finding was “an interesting piece of the puzzle,” though he said it was “not in itself definitive and highlights the need for a more thorough investigation.”