Update on the human immunodeficiency virus.

At the end of 2011, UNAIDS estimated that 34 million (31.4 to 35.9) individuals were infected by HIV worldwide and that 2.5 million were newly infected during the year. Since 2001, we have observed an increased number of HIV-infected patients in the world, due to an expanded access to antiretroviral drugs. More than 23,5 million (22.1 to 24.8) HIV-infected patients live in Sub-Saharan Africa. The number of HIV-infected patients in France is estimated at 152,000. Two types of HIV cause AIDS: HIV-1 and HIV-2 that are subdivided in groups (M, N, O, P for HIV-1; A to H for HIV-2), subtypes (A-D, F-H, J-K for HIV-1 group M), sub-subtype (A1-A4 for subtype A, F1 and F2 for subtype F in HIV-1 group M), circulating recombinant forms (CRF), and unique recombinant forms in a small number of patients. Virological diagnostic and monitoring techniques have been constantly upgraded since HIV-1 was isolated in 1983 and the first serological tests became available in 1985. This is especially true for HIV-1, the most prevalent worldwide.