liú xíng bìng xué jiā / tōng guò / zhuī zōng / bìng lì / shì tú / què rèn / zhè cì / yì qíng / de / líng hào bìng rén

流行病学家通过追踪病例，试图确认这次疫情的零号病人。

Epidemiologists tracked the cases in an attempt to identify the patient zero of this outbreak.