Epidemiological characteristics of human immunodeficiency virus type-2 infection in Africa

There are things yet to be clarified about African HIV-2 infection, compared to HIV-1 infection. However, the epidemiological characteristics have gradually been elucidated through various studies. HIV-2 infection is believed to have existed in the 1960s in Africa and is presently epidemic in West Africa. The HIV-2 seropositive rate for the general population is higher in urban regions than in rural areas. The peak age of persons infected with the HIV-2 tends to be higher than that of persons infected with the HIV-1, but no sex difference was recognized between the HIV-2 and HIV-1 seropositive rates. Sexual contact, mother-to-child transmission and blood transfusion have been confirmed as HIV-2 transmission modes. Prostitutes and patients with other STD are recognized as being high-risk groups for the HIV-2 infection. Patients who are infected with both HIV-1 and HIV-2 have also been identified, but it is suggested that the pathogenicity of HIV-2 is lower than that of HIV-1.