Molecular characterization of human immunodeficiency virus type 1-infectedindividuals from Bolivia reveals the presence of two distinct genetic subtypes B and F

Thirty HIV-1-positive samples from Bolivia were genetically characterized o n the basis of HMA and DNA sequencing, revealing the presence of B and F su btypes, in accordance with the molecular epidemiology pattern already descr ibed for other South American countries such as Brazil and Argentina. The i nterpatient divergence of subtype B Bolivian specimens was on average 14.2% (4.3-19.8%) at the nucleotide level, whereas the two unlinked subtype F sa mples (BO23 and BO29) were only 8.2% divergent, suggesting a more recent in troduction of this subtype in the country. In our study group, which repres ents 13% of the HIV/AIDS cases already described in Bolivia as of May 1996, the transmission occurred more frequently through heterosexual exposures ( 46.7%), followed by homosexual (23.3%), bisexual (10%), intravenous drug us e (3.3%), and vertical (3.3%); in one case the potential exposure category could not be defined (3.3%). No association could be established between ex posure categories, gender, or clinical classification and subtype distribut ion in the Bolivian HIV/AIDS patients.