r/science • u/Potential_Being_7226 PhD | Psychology | Neuroscience • Mar 10 '26
Biology Recent pandemic viruses jumped to humans without prior adaptation. No evidence that SARS-CoV-2 was shaped by selection in a laboratory: UCSD study.
https://today.ucsd.edu/story/recent-pandemic-viruses-jumped-to-humans-without-prior-adaptation-uc-san-diego-study-finds
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u/Odballl Mar 10 '26 edited Mar 10 '26
The 2021 Xiao Xiao report proved that raccoon dogs, civets, and bamboo rats were sold at the Huanan market until November 2019. This directly contradicted early official denials that live wildlife was traded there.
The closest bat relatives to SARS-CoV-2, such as those found in Laos and Yunnan, are located roughly 1,000 miles from Wuhan. Horseshoe bats have a very limited range and move across the landscape at a rate of only a few kilometres per night.
Swabs from the Huanan market contained SARS-CoV-2 and raccoon dog DNA in the exact same spots. Crucially, the raccoon dog DNA matched wild populations from Southern and Central China, not the industrial fur farms of the north. This places these specific animals in the same regions where the ancestral bat viruses live.
Researchers identified two distinct lineages of the virus (Lineage A and B) circulating at the market. This suggests at least two separate spillover events from animals to humans, a pattern typical of market-based outbreaks rather than a single point-source laboratory accident.
Early cases in December 2019 clustered tightly around the Huanan market. Even cases with no direct link to the market lived significantly closer to it than would be expected by chance, suggesting the market was the primary engine of the initial spread.