This Radiolab episode explores the concept of "Patient Zero" through three distinct narratives. It begins with Typhoid Mary, the first documented healthy carrier of typhoid fever, and her controversial quarantine. The show then debunks the myth of Gaëtan Dugas as the origin of the AIDS epidemic, tracing HIV’s true roots to a chimpanzee spillover in Cameroon around 1908. Finally, it investigates the invention of the high-five, contrasting a fabricated college athlete story with the tragic life of Glenn Burke, the gay baseball player who likely popularized the gesture.