Virological and polymerase chain reaction studies of HIV-1/HIV-2 dual infection in Côte d'Ivoire

Dual serological reactivity to the human immunodeficiency virus (HIV) types 1 and 2 is common in Côte d'Ivoire. To assess whether dual infection is the reason for dual seropositivity we sought HIV-1 and HIV-2 proviral DNA in primary uncultured peripheral blood mononuclear cells from selected seropositive patients in Côte d'Ivoire with the polymerase chain reaction (PCR). PCR on primary lymphocytes in 36 dually seropositive samples revealed the presence of both HIV-1 and HIV-2 proviral DNA in 12 cases and the presence of HIV-1 only in 24 cases. In 18 of these 36 samples a virus was isolated and identified by PCR. HIV-1 was isolated from the 9 specimens with only HIV-1 proviral DNA in the primary lymphocytes. Among dually PCR-positive samples, 2 viral isolates reacted with both HIV-1 and HIV-2 primers; and only HIV-2 (n=1) or HIV-1 (n=6) strains were isolated from the other samples. The findings show that surveys based on serology may overestimate the prevalence of mixed infections in areas where both HIV-1 and HIV-2 occur.