HIV can be divided into two major types, HIV type 1 (HIV-1) and HIV type 2 (HIV-2). HIV-1 is related to viruses found in chimpanzees and gorillas living in western Africa, while HIV-2 viruses are related to viruses found in the endangered west African primate sooty mangabey.
HIV-2 has been found to be less pathogenic than HIV-1.
HIV-2 has not been widely recognized outside of Africa. The first case in the United States was in 1987.
As of 2010, there are 8 known HIV-2 groups (A to H). Of these, only groups A and B are pandemic. Group A is found mainly in West Africa, but has also spread globally to Angola, Mozambique, Brazil, India, Europe, and the US. Despite the presence of HIV-2 globally, Group B is mainly confined to West Africa.