HIV-1 subtypes among blood donors from Rio de Janeiro, Brazil

The prevalence of HIV infection in Brazil is one of the highest in the worl d. In addition, transfusion-transmitted HIV accounts for 2.3% of all AIDS c ases in Brazil. The objective of this study was to evaluate genetic diversi ty and distribution of HIV-1 strains circulating in the blood-donor populat ion. We characterized 43 seropositive blood units collected from volunteer blood donors residing throughout Rio de Janeiro, Brazil. Viral RNA was extr acted from plasma, reverse transcribed, and amplified by nested polymerase chain reaction (PCR) using HIV group M degenerate primers. Genetic heteroge neity was evaluated by direct automated cycle sequencing of the following g ene fragments: gag p24 (399 bp), env C2V3 (345 bp), and env gp41 (369 bp). Phylogenetic analysis reflected the complexity of the Brazilian HIV epidemi c: the majority of specimens, 33 of 43 (76.7%) were subtype B, and 6 of 43 (14%) were subtype F. The remaining 4 samples (9.3%) involved potential mos aic viruses of subtypes B and F or B and D. This survey is the first to doc ument HIV-1 genetic variation in the Brazilian blood-donor population.