summary - China CDC’s own environmental and animal surveillance at the Huanan market: 923 environmental swabs collected from 1 January 2020 (the day the market was closed and disinfection began) and 457 samples from animal-origin material (unsold refrigerator/freezer stock, strays, a fish tank, covering 18 species) from 18 January 2020. No animal-origin sample tested SARS-CoV-2-positive, but 74 environmental swabs did (mostly concentrated in the section that sold live wildlife), including one yielding a lineage-A genome. This is also the primary documentary source for the market’s closure-then-sampling timeline: closed and disinfection begun 1 Jan 2020, CDC swabbing starting the same day, animal-sample collection starting over two weeks later (18 Jan), after most live animals had already been removed. Note for balance: because no animal tissue itself tested positive, the paper’s own data cannot show an infected animal directly — the co-located-DNA argument for an infected intermediate host comes from the separate reanalysis of this same raw data (this slice’s other market-swab node).
relevance_note - China’s own primary market-surveillance dataset; establishes the closure/sampling timeline and the environmental-positivity pattern that both Worobey 2022’s case-geolocation paper and the international reanalysis build on — flag as the shared data-basis for step 2 (same raw samples, independent interpretations).