In the tortuous mythology of the AIDS epidemic, one legend never seems to die: Patient Zero, aka Gaétan Dugas, a globe-trotting, sexually insatiable French Canadian flight attendant who supposedly picked up HIV in Haiti or Africa and spread it to dozens, even hundreds, of other men before his death in 1984.
But after a new genetic analysis of stored blood samples, bolstered by some intriguing historical detective work, scientists on Wednesday declared him innocent.
The strain of HIV responsible for almost all AIDS cases in the United States, which was carried from Zaire to Haiti around 1967, spread from there to New York City around 1971, researchers concluded in the journal Nature. From New York, it spread to San Francisco around 1976.
The new analysis shows that Dugas' own blood, sampled in 1983, contained a viral strain already infecting men in New York before he began visiting gay bars here after being hired by Air Canada in 1974.
Myths like that of Patient Zero echo in prevention efforts even today, experts said. Many vulnerable groups, including young gay men and African women, fail to use protective drugs or avoid testing because they fear being stigmatized or accused of being carriers.
Reflecting on the epidemic's early days, Dr. Anthony S. Fauci, then a doctor treating AIDS patients and now the director of the National Institute of Allergy and Infectious Diseases, said he remembered it seeming plausible at the time that one person was responsible.
In hindsight, he added, the idea now seems absurd. "We were unaware of how widespread it was in Africa," Fauci said.
The new data are consistent with the scenario described in 2011 in The Origins of AIDS, by Dr. Jacques Pépin, an infectious disease specialist at the University of Sherbrooke in Quebec. Relying on previous genetic research and African colonial records, Pépin showed that HIV was carried from Kinshasa to Haiti in the 1960s.
The blood samples analyzed in the new study were collected in 1978 and 1979 in New York and San Francisco as part of an effort to make a hepatitis B vaccine.