One of the most demonised patients in history – Gaetan Dugas has been convincingly cleared of claims he spread HIV to the US, say scientists.
Mr Dugas, a homosexual flight attendant, gained legendary status in the history of HIV/Aids when he became known as Patient Zero.
But a study, in the journal Nature, showed he was just one of thousands of infected people in the 1970s.
It also showed New York was a crucial hub for the spread of the virus.
Aids only started to be recognised in 1981 when unusual symptoms started appearing in gay men.
But researchers were able to look further back in time by analysing stored blood samples, some of them containing HIV, from hepatitis trials in the 1970s.
The team at the University of Arizona developed a new method to reconstruct the genetic code of the virus in those patients.