The details are really surprising for their simplicity, and for illustrating how a "good" but mistaken story gets spread and takes a long, long time to correct. Ed Yong explains that, when first investigating the rise of AIDS in the US, the researchers found this:
One of those 40 cases was a Canadian flight attendant named Gaëtan Dugas. Having had sex with patients from both California and New York, he seemed to connect the epidemic from coast to coast. As the 57th AIDS patient to reach the CDC team’s attention, Dugas was originally billed as Case 057. But since he came from outside California, and wasn’t even a
U.S. resident, the investigators started referring to him offhandedly as the “Out-of-California patient”—or “Patient O” for short.
That was an unfortunate move. “When the study got written up and was circulated beyond the immediate team to other people within the CDC, that ambiguous oval got interpreted by some as a zero,” says Richard McKay, a medical historian at the University of Cambridge, who recently tracked down the details of the case. By the time the CDC study was published in 1984, Patient O had become Patient 0. In the paper’s sole diagram, Dugas sits at the center, like the spider in a web of disease.
Labels have power. As “Patient Zero,” with its connotations of ground zero, Dugas came across as not just the center of that particular AIDS cluster, but as the source of the entire U.S. epidemic. The CDC team did their best to naysay this misconception, but it gained steam globally in 1987, after the journalist Randy Shilts published his bestselling book And The Band Played On. Shilts identified Dugas by name, and while he never specifically claimed that the man was the source of the U.S. AIDS epidemic, reviewers and media commentators weren’t so restrained.
The idea fit with the prejudices of the day: Here was a modern Typhoid Mary, whose homosexuality and irresponsible promiscuity had brought a plague to American shores.
“Whether it’s explicit or not, there’s always a focus on the potential moral failings of the first recognized individual,” says McKay. But the concept of Patient Zero has been weakening for years, with several lines of evidence showing that HIV—the virus behind AIDS—likely arrived in the U.S. well before Dugas was ever infected.
Now, a new study exonerates Dugas once and for all. It combines McKay’s historical detective work with genetic evidence compiled by Michael Worobey, an evolutionary biologist at the University of Arizona. He sequenced the complete genomes of HIV taken from U.S. samples collected in the late 1970s, and showed that Dugas could not possibly have been the first AIDS patient in the U.S. Indeed, the disease likely entered the country from Haiti in 1971, flying under the radar for a decade before anyone realized what was happening.