AIDS existed in the 70s, it was silent.
.....it wasn't until the 1981 when the US CDC recorded a cluster of Pneumocystis carinii pneumonia in five homosexual men in Los Angeles.
Three of the earliest known instances of HIV infection are:
A plasma sample taken in 1959 from an adult male living in Kinshasa, today part of the Democratic Republic of the Congo.[147]
HIV found in tissue samples from "Robert R.", a 15 year old African-American teenager who died in St. Louis in 1969.[148]
HIV found in tissue samples from Arvid Noe, a Norwegian sailor who died around 1976.[149]
Two species of HIV infect humans: HIV-1 and HIV-2. HIV-1 is more virulent and more easily transmitted. HIV-1 is the source of the majority of HIV infections throughout the world, while HIV-2 is not as easily transmitted and is largely confined to West Africa.[150] Both HIV-1 and HIV-2 are of primate origin. The origin of HIV-1 is the Central Common Chimpanzee (Pan troglodytes troglodytes) found in southern Cameroon.[151] It is established that HIV-2 originated from the Sooty Mangabey (Cercocebus atys), an Old World monkey of Guinea Bissau, Gabon, and Cameroon.
Most experts believe that HIV probably transferred to humans as a result of direct contact with primates, for instance during hunting or butchery.[152] A more controversial theory known as the OPV AIDS hypothesis suggests that the AIDS epidemic was inadvertently started in the late 1950s in the Belgian Congo by Hilary Koprowski's research into a poliomyelitis vaccine.[153][154] According to scientific consensus, this scenario is not supported by the available evidence.[155][156][157]
A recent study states that HIV probably moved from Africa to Haiti and then entered the United States around 1969.[158]