The first known infections from SARS‑CoV‑2 were discovered in Wuhan, China.[17] The original source of viral transmission to humans remains unclear, as does whether the virus became pathogenic before or after the spillover event.[19][75][9] Because many of the early infectees were workers at the Huanan Seafood Market,[76][77] it has been suggested that the virus might have originated from the market.[9][78] However, other research indicates that visitors may have introduced the virus to the market, which then facilitated rapid expansion of the infections.