The New York Post once described Gaétan Dugas, a French Canadian flight attendant, under the incendiary headline "The Man Who Gave Us AIDS." Known colloquially as "Patient Zero," Dugas figured prominently in Chronicle journalist Randy Shilts's 1987 And the Band Played On. Shilts invented the term in that volume, misreading "Patient O" as in the letter, as zero, as in the number. The letter merely signified that he was from "Outside" of the country — other letters like "NY" might have meant New York, to give one example.

At the time, the term "Patient Zero" wasn't even established to mean the first case of a disease or virus — but it soon came to signify just that, and with it, Dugas (who died in 1984) has long carried blame for the spread of the deadly virus. But a new study published in the journal Nature and picked up by the Times this week debunks that thinking, folklore that is itself symptomatic of a culture that created and trafficked in pariahs. Strains of HIV arrived in New York in 1971 and SF in 1976 according to the new research, and analysis shows that Dugas's blood, which was sampled in 1983, had a viral strain of HIV that predated his arrival in New York.

“It’s a great example of the latest science technology being applied to answer questions from so long ago,” Dr. Paul Volberding, director of the AIDS Research Institute at UCSF and an early treater of HIV positive and AIDS patients told the Chronicle, who also covered the study. "We're still gaining insight into how this epidemic spread — how rapidly it spread, where it spread — even now, 35 and apparently a whole lot more years later.”

The Nature study was co-authored by Michael Worobey, an evolutionary biologist at the University of Arizona at Tucson, and Richard McKay, a historian at the University of Cambridge. To conduct it, scientists used blood samples taken from New York men and San Francisco men who had participated in a hepatitis B vaccine study in the late '70s. Six percent of the NY samples and 3 percent of the SF samples were found to have HIV at the time. After so many years, new lab techniques were needed to gather information about the time-degraded blood samples. But using mathematical models and parsing different strains, “You can really come up with a rich model of how a virus moves through space and time,” says UCSF scientist Satish Pillai, who spoke to the Chronicle. It's that timeline that essentially exonerates Dugas.

The Times recalls that Dugas became a central figure in part because he was candid about his prodigious sex life, keeping a diary and providing names of sex partners to investigators. Shilts himself died of AIDS a decade later in 1994, and was initially reluctant to characterize Dugas as he eventually did — demonizing him partly through a publicity campaign for his 1987 book. Of course, fans of the 1993 Canadian musical film Zero Patience will have little time for a reexamination of the urban legend.

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