HIV AIDS

HIV Origin Story

by Zoltan Fehervari 11/18/2018 Nature

More recent molecular timing and modeling studies have pushed back the earliest appearance of M group HIV-1 to around the beginning of the twentieth century. This would suggest that HIV-1 was circulating cryptically in Africa for generations before factors such as urbanization and mass movement of people propelled it onto the global stage. 
AIDS was first described as a new disease in 1981 (MILESTONE 1), and the causative lentivirus that came to be known as HIV-1 was identified a couple of years later (MILESTONE 2). However, the origins of HIV-1 and the reasons for its explosive appearance and rapid transformation into a global epidemic remained a mystery.
The inklings of an answer began to emerge from two West African patients presenting with an antigenically distinct AIDS-causing virus that subsequently came to be known as HIV-2 (MILESTONE 6). Genetically distant from HIV-1, HIV-2 was instead shown to be closely related to a lentivirus infecting an African monkey—the sooty mangabey. Subsequent studies confirmed that lentiviruses are endemic to many species of African monkeys and some apes—and these have collectively become known as simian immunodeficiency viruses (SIVs). Sooty mangabeys in particular were found to be naturally infected with a lentivirus known as SIVsmm (with the subscript indicating the name of the infected species), and genetic evidence showed that this virus was transmitted to humans, generating the HIV-2 epidemic.