How did HIV spread wordwide? This is one of the most obscure mysteries of the AIDS. A recent paper published in PNAS journal provides an answer for the initial steps of the disease after leaving Africa in 60s. As Dr. Worobey said:
«Our results show that the strain of virus that spawned the U.S. AIDS epidemic probably arrived in or around 1969. That is earlier than a lot of people had imagined, [..] Haiti was the stepping stone the virus took when it left central Africa and started its sweep around the world,»
The «USA first model» has been the most accepted for scientific community for several years and with these new data it could be possible to reorganize the different HIV strains and learn how the HIV mutated and diversified. Take together this info could help with the vaccine development.
This paper reminds me the OPV-AIDS hypothesis, which argues that AIDS originated from live polio vaccines prepared in chimpanzee tissue cultures which were administered to up to one million Africans between 1957 and 1960.