Kirby Institute, University of New South Wales, Sydney, NSW
Last reviewed: December 2018
The acquired immune deficiency syndrome (AIDS) is caused by the human immunodeficiency virus (HIV). HIV-1 was initially identified by Luc Montanier at the Institute Pasteur, Paris, in 1983  and was then more fully characterized in 1984 by Robert Gallo in Washington  and Jay Levy in San Francisco [3, 4]. A second virus, HIV-2, was isolated from West African patients in 1986 . Viruses similar to HIV-1 and HIV-2 have been isolated from chimpanzees and wild African monkeys . It is most likely that HIV-1 and HIV-2 crossed species from primates to humans in Africa several times over the last hundred years with the earliest known samples of HIV-1 isolated from preserved tissues samples from 1959 and 1960 [6-8]. The genetic diversity of these two HIV-1 isolates at that time estimates the most recent common ancestor for HIV-1 to be around 1908 [6-8].