Did COVID-19 begin with raccoon dogs?

The weight of evidence—scientific and epidemiological—points to a zoonotic origin for SARS-CoV-2 with the epicenter at the Huanan wet market in Wuhan, China. Although the virus is endemic in bats, there’s little evidence for a direct jump of the virus from bats to humans in Wuhan. The most parsimonious hypothesis is that some other mammal intermediated the transmission.

While several animals known to be at the wet market have been suspects, the raccoon dog (which is not related to raccoons) is at the top of the list. Recent review of the data supports this inference:

“Today, mounting evidence from more than a dozen studies point to a person, or people, catching the virus from a wild animal or animals at the Huanan Seafood Market in Wuhan, China, the city at the epicentre of the outbreak. And the animal at the top of the list is the raccoon dog (Nyctereutes procyonoides).

“There is a large focus on raccoon dogs,” says Kristian Andersen, an evolutionary biologist at Scripps Research in La Jolla, California.

“Some scientists, including virologist Edward Holmes at the University of Sydney in Australia, have suspected raccoon dogs all along.”

*snip*

“Most researchers agree that SARS-CoV-2 probably originated in Rhinolophus bats living in Yunnan, southern China, in Laos, or other parts of southeast Asia, in part because that’s where the virus’s closest known relatives have been found.

“Scientists have been trying to figure out how the virus got from those regions to Wuhan — a journey of more than 1,000 kilometres — which is well outside the hotspots where these viruses circulate in bats.

“That’s why it is important to consider the geographic ranges of suspect intermediate animals to see whether they overlap with those bats, says Alex Crits-Christoph, a computational biologist at a non-profit organization, based in Baltimore, Maryland. Among the animals at the Huanan market, the ranges of wild raccoon dogs, civets, hoary bamboo rats and greater hog badger overlap with that of the bats. Fitting with this hypothesis, the mitochondrial DNA from raccoon dogs at the Huanan market did not match those from farmed animals in northeastern China, and were instead closer to wild-caught animals in central and southern China.”

Is this proof of a zoonotic origin? No. Is this proof that the pandemic began with a customer or vendor at the wet market who was exposed to an infected raccoon dog? No. Science doesn’t deal in proof, it deals in the weight of evidence. If you want metaphysical certitude, you are talking about religion, not science. The weight of scientific and epidemiological evidence as of now points strongly to a zoonotic origin, with a probable transmission via infected raccoon dogs.

https://www.nature.com/articles/d41586-025-00426-3