Katherine J. Wu writes:

For three years now, the debate over the origins of the coronavirus pandemic has ping-ponged between two big ideas: that SARS-CoV-2 spilled into human populations directly from a wild-animal source, and that the pathogen leaked from a lab. Through a swirl of data obfuscation by Chinese authorities and politicalization within the United States, and rampant speculation from all corners of the world, many scientists have stood by the notion that this outbreak—like most others—had purely natural roots. But that hypothesis has been missing a key piece of proof: genetic evidence from the Huanan Seafood Wholesale Market in Wuhan, China, showing that the virus had infected creatures for sale there.

This week, an international team of virologists, genomicists, and evolutionary biologists may have finally found crucial data to help fill that knowledge gap. A new analysis of genetic sequences collected from the market shows that raccoon dogs being illegally sold at the venue could have been carrying and possibly shedding the virus at the end of 2019. It’s some of the strongest support yet, experts told me, that the pandemic began when SARS-CoV-2 hopped from animals into humans, rather than in an accident among scientists experimenting with viruses.

“This really strengthens the case for a natural origin,” says Seema Lakdawala, a virologist at Emory University who wasn’t involved in the research. Angela Rasmussen, a virologist involved in the research, told me, “This is a really strong indication that animals at the market were infected. There’s really no other explanation that makes any sense.” [Continue reading…]