The first recognised cases of AIDS occurred in the USA in the early 1980s (see timeline) and the origin of Aids and HIV has puzzled scientists ever since the illness first came to light. For years it has been the subject of fierce debate and the cause of countless arguments.
A number of gay men in New York and California suddenly began to develop rare opportunistic infections and cancers that seemed stubbornly resistant to any treatment in 1981. At this time, AIDS did not yet have a name, but it quickly became obvious that all the men were suffering from a common syndrome. The discovery of HIV, the Human Immunodeficiency Virus, was made soon after. While some were initially resistant to acknowledge the connection (and indeed some remain so today), there is now clear evidence to prove that HIV causes AIDS. But, what was the source of the virus and when and where did HIV first begin to cause disease in humans?
There are several subtypes of HIV that are prevalent in different parts of the world. The earliest known case of any type of HIV in a human was from a blood sample analysed in 1998 but collected in 1959. This suggested that HIV/Aids might have been introduced to humans in the 1940s or early 1950s. However, in January 2000 (San Francisco, California) the results of a new study presented at the 7th Conference on Retroviruses and Opportunistic Infections, suggested that the first case of HIV infection occurred around 1930.
In 1999, an international team of researchers reported that a subspecies of chimpanzee, native to west equatorial Africa, was the original source of the virus. They believe that it passed to humans when hunters became exposed to infected blood.