Genetic diversity and phylogenetic analysis of human immunodeficiency virus type 1 subtypes circulating in French Guiana.

We investigated the characterization of different HIV-1 subtypes present in French Guiana by use of three different methods. Serological methods were used for the initial screening, which were then confirmed by the heteroduplex mobility assay (HMA). The V3 env region was subsequently sequenced for phylogenetic analysis, to confirm the subtype of the samples, and to assign a subtype to samples that gave results that were difficult to interpret or discordant by serology or HMA. A total of 221 HIV-1 seropositive samples were typed; 110 of them were confirmed by HMA and 16 were sequenced. Of the 221 samples tested 210 patients (95%) were found to be infected with subtype B, 10 (4.5%) were infected with subtype A, and one patient was infected with subtype F. Phylogenetic analysis demonstrated that the strains from French Guiana were closely related to the subtype A and B subtypes, and that one strain was closely related to an F subtype (100% bootstrap value). Four strains from French Guiana clustered in the subtype A (99% bootstrap value) and the other strains were associated with subtype B (100% bootstrap value). The geographic position of French Guiana suggested that HIV-1 was probably introduced into the country via several routes, and thus the pattern of the HIV-1 epidemic might evolve in the near future.