The researchers analyzed hundreds of samples that were collected by Chinese officials in Wuhan, China in January 2020 at the onset of Covid-19, BBC reports. The officials swabbed various places at the Huanan Seafood Wholesale Market including animal cages and equipment used to clean slaughtered animals after several people who were there at the same time ended up in the hospital with a "mystery pneumonia."
While the Chinese officials published their analysis of the samples last year, the new research team from the US and France claimed they've analyzed the data with more advanced genetic methods involving DNA and RNA to trace what animals were in the Wuhan market in January 2020.
"We are seeing the DNA and RNA ghosts of these animals in the environmental samples, and some are in stalls where [the Covid virus] was found too," said Professor Florence Débarre of the French National Centre for Scientific Research.
Professor Kristian Andersen from the Scripps Institute in the US stated, "We find a very consistent story in terms of this pointing - even at the level of a single stall - to the market as being the very likely origin of this particular pandemic."
Essentially, the researchers found that animals susceptible to the Covid virus such as raccoon dogs and the Covid virus itself were close in proximity. Some of the swabs picked up both coronavirus and animal genetic material. The researchers were not able to prove that the animals were infected but said that raccoon dogs specifically are capable of transmitting the virus.
The data revealed that there were two potential instances of Covid being transmitted from animals to humans in the market and that the outbreak at the market most likely started at the same time as the pandemic in humans.
“If we estimate when do we believe most likely the pandemic started versus when do we believe most likely the outbreak at the market started, these two overlap, they’re one and the same,” Andersen said.
Professor Michael Worobey from the University of Arizona, stated: "Rather than being one small branch on this big bushy evolutionary tree, the market sequences are across all the branches of the tree, in a way that is consistent with the genetic diversity actually beginning at the market," adding that, in his opinion, all the data pointed to an animal origin of Covid. “It's far beyond reasonable doubt that this is how it happened”, and that other explanations for the data required "really quite fanciful absurd scenarios," he said. "I think there's been a lack of appreciation even up until now about how strong the evidence is."
