HIV-2, which is closely related to SIV from sooty mangabeys, was first identified in 1986 in patients with AIDS in Guinea-Bissau and Cape Verde, West Africa. Like HIV-1, HIV-2 is an immunodeficiency virus that causes AIDS in humans. However, although HIV-1 and HIV-2 are related, there are important structural differences between them which influence pathogenicity, natural history and therapy.
The HIV-2 epidemic has its epicentre in West Africa, and is also found in those countries that have had historical colonial links with the region, in particular Portugal and France. Sociocultural issues such as civil war and migration have had major impacts on the spread of HIV-2. Recent data from Guinea-Bissau suggest that the incidence of HIV-2 is now falling, in contrast to that of HIV-1, which has remained stable since 1999 . Diagnoses of HIV-2 are increasing in India but in Europe and the United States the prevalence remains low [2–4]. HIV-2 does not protect against HIV-1 and dual infection is observed. In the United Kingdom, approximately 137 HIV-2 monoinfections and 35 HIV-1 and HIV-2 dual infections have been reported to the Health Protection Agency (HPA) .
Y Gilleece, DR Chadwick, J Breuer, D Hawkins, E Smit, LX McCrae, D Pillay, N Smith and J Anderson on behalf of the BHIVA Guidelines Subcommittee. See Appendix for list of members of the BHIVA Guidelines Writing Group on HIV-2.
HIV Medicine (2010) , 11, 611–619.