Subtypes of HIV - Major Types - HIV-2

HIV-2

HIV-2 has not been widely seen outside of Africa. The first case in the United States was in 1987. Many test kits for HIV-1 will also detect HIV-2.

As of 2010, there are 8 known HIV-2 groups (A to H). Of these, only groups A and B are epidemic. Group A spread mainly in West Africa, but also to Angola, Mozambique, Brazil, India, and very limitedly to Europe or the US. Group B is mainly confined to West Africa.

HIV-2 is mostly related to simian immunodeficiency virus endemic in sooty mangabeys (Cercocebus atys atys) (SIVsmm), a monkey species inhabiting the forests of littoral West Africa. Phylogenetic analyses show that the viruses most closely related to the two strains of HIV-2 which spread considerably in humans (HIV-2 groups A and B) are the SIVsmm found in the sooty mangabeys of the Tai forest, in western Ivory Coast.

There are six additional known HIV-2 groups, each having been found in just one person. They all seem to derive from independent transmissions from sooty mangabeys to humans. Groups C and D have been found in two people from Liberia, groups E and F have been discovered in two people from Sierra Leone, and groups G and H have been detected in two people from the Ivory Coast. Each of these HIV-2 strains, for which humans are probably dead-end hosts, is most closely related to SIVsmm strains from sooty mangabeys living in the same country where the human infection was found.