New studies agree that animals sold at Wuhan market are most likely what started

CNN
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In June, the World Health Organization recommended that scientists continue to research all possible origins of the Covid-19 pandemic, including a lab leak. Two newly published studies take totally different approaches but arrive at the same conclusion: The Huanan Seafood Market in Wuhan, China, was most likely the epicenter for the coronavirus.

The studies were posted online as preprints in February but have now undergone peer review and were published Tuesday in the journal Science.

In one, scientists from around the world used mapping tools and social media reports to do a spatial and environmental analysis. They suggest that although the “exact circumstances remain obscure,” the virus was probably present in live animals sold at the market in late 2019. The animals were held close together and could easily have exchanged germs. However, the study does not determine which animals may have been sick.

The researchers determined that the earliest Covid-19 cases were centered at the market among vendors who sold these live animals or people who shopped there. They believe that there were two separate viruses circulating in the animals that spilled over into people.

“All eight COVID-19 cases detected prior to 20 December were from the western side of the market, where mammal species were also sold,” the study says. The proximity to five stalls that sold live or recently butchered animals was predictive of human cases.

“The clustering is very, very specific,” study co-author Kristian Andersen, a professor in the Department of Immunology and Microbiology at Scripps Research, said Tuesday.

The “extraordinary” pattern that emerged from mapping these cases was very clear, said another co-author, Michael Worobey, department head of Ecology and Evolutionary Biology at the University of Arizona.

The researchers mapped the earliest cases that had no connection to the market, Worobey noted, and those people lived or worked in close proximity to the market.

“This is an indication that the virus started spreading in people who worked at the market but then started that spread … into the surrounding local community as vendors went into local shops, infected people who worked in those shops,” Worobey said.

The other study takes a molecular approach and seems to determine when the first coronavirus infections crossed from animals to humans.

The earliest version of the coronavirus, this research shows, probably came in different forms that the scientists call A and B. The lineages were the result of at least two cross-species transmission events into humans.

The researchers suggest that the first animal-to-human transmission probably happened around November 18, 2019, and it came from lineage B. They found the lineage B type only in people who had a direct connection to the Huanan market.

The authors believe that lineage A was introduced into humans from an animal within weeks…