Diversity of HIV-1 subtype C strains isolated in Romania

Two unique aspects particularities of the HIV-1 epidemics in Romania are the high prevalence of subtype F1 strains and the large pediatric population infected in the late 1980s and early 1990s. During recent years, more infections with other subtypes have been seen in newly diagnosed patients. After subtype B, subtype C was the most frequent one. This subtype is prevalent in countries from sub-Saharan Africa and India, being responsible for half of the total HIV-1 infections in the world. We have identified 37 patients infected with subtype C, sequenced the reverse transcriptase and protease regions of their pol genes, and applied phylogenetic analyses to the sequences. We have also included 20 subtype F1 strains isolated from both teenagers (children at the time of diagnosis) and adults. The phylogenetic analysis was performed by using the PhyML method, the GTR (general time reversible) model of evolution and gamma distribution of variability of rates between sites, empirically calculated from the data. The epidemiological data indicates that the main route of transmission for the adult subjects was by heterosexual contact and a relatively small number of patients were possibly infected abroad. In three cases, blood transfusion prior to 1989 or surgical procedures at early ages were suspected to be the cause of the HIV infection and three other patients were most probably parenterally infected. The phylogenetic analyses showed that the Romanian C strains are very diverse overall, clustered in several groups characterized by common transmission route (transfusion/surgical procedures) or local geographical relatedness. The HIV-1 epidemics in Romania apparently followed different patterns for subtypes F and C. While subtype F1 seems to have been monoclonally introduced and extensively spread in the 80s, the subtype C strains, although present in the late 80s, failed to spread to the same extent.