A study of seroprevalence of HIV-1 and HIV-2 in six provinces of People's Republic of Angola: clues to the spread of HIV infection.

A seroepidemiological study was carried out to determine the distribution of the human immunodeficiency viruses type 1 (HIV-1) and type 2 (HIV-2) in the People's Republic of Angola, where HIV-2 existence was previously unknown and HIV-1 seropositivity was only reported to be present in Luanda and Cabinda. A total of 1,695 serum samples were obtained from healthy persons (control group) and from a group of patients in the provinces of Zaire (13), Lunda-Norte (L.N.) (749), Luanda (556), Huambo (154), Kuando-Kubango (K.-K.) (49), and Namibe (119). All samples were tested for HIV-1 and HIV-2 antibodies by enzyme-linked immunosorbent assay and an indirect immunofluorescence assay using MOLT-T4 cells. Positive samples were confirmed by the Western-blot technique. Sera giving cross reactivity at the level of HIV-1 and HIV-2 large glycoproteins were further tested by radioimmunoprecipitation assay and by reactivity against a peptide corresponding to the dominant epitope of the transmembrane protein. The overall seroprevalance was 14.2%, with significantly higher values in the patient group [19.4% (HIV-1 = 8.8%; HIV-2 = 8.4%; HIV-1 + HIV-2 = 2.2%)] than the control group [9.3% (HIV-1 = 3.3%; HIV-2 = 5.3%; HIV-1 + HIV-2 = 0.7%)]. HIV-2 as well as HIV-1 infection is actually present in Angola in all studied provinces. Higher seroprevalence was seen in the provinces of Zaire, Lunda Norte, and Huambo. People displacements, mainly as a consequence of the war, certainly play an important role in spreading HIV infection from the northern frontier areas of the country to the central and southern regions.