HIV, the AIDS-causing virus, may have settled in America during the early 70s. The disease has long been established before medical experts found the microbe fueling its spread.

The analysis dispels the long-believed theory that a flight attendant of French-Canadian descent slept with numerous men in New York and California to trigger the epidemic in the 80s.

Blood samples from the man known as Patient Zero and those extracted from associated or infected individuals during the late 70s have been taken in for hepatitis B testing. The investigation apparently supports the new claim.

After isolating eight HIV cases, viral genomes are then classified. Findings suggest that the pathogen is already in circulation during the targeted decade. Prior to its spread in the US back in 1967, it is believed that the virus has jumped from Africa to the Caribbean. From there, the HIV invades New York in 1971 and by 1976, it was already in San Francisco.

Researchers have discovered that genome sequences are similar among the eight cases examined which means that the pathogen has already affected America in the late 70s.

In a 2007 study entitled Proceedings of the National Academy of Sciences, Michael Worobey, head of the University of Arizona's Department of Ecology and Evolutionary Biology, cites that HIV found on Patient Zero's blood samples closely resembles those discovered on the ones taken from homosexual men from 1975 to 1979.

Perhaps the only thing linking Patient Zero, who is identified as Gaetan Dugas, to many AIDS victims is his extensive knowledge about the men he had sex with. During the course of the research, investigators at the US Centers for Disease Control and Prevention have used the flight attendant's name a little too often to link the sexual transmissions.

Meanwhile, investigator William Darrow points out that the Patient Zero narrative has been misinterpreted. The Dugas file has been named patient 'O,' which meant Outside-of-California status. Along the way, the 'O' becomes zero. This apparently reinforces the flight attendant's standing as Patient Zero.