High levels of HIV genetic variability among female sex workers in Argentina.

PANDO MA; BAUTISTA CT; EYZAGUIRRE LM; CARRION G; MARONE R; MONTANO S; SANCHEZ J; CARR JK; AVILA MM

Toronto

Conferencia; XVI International AIDS Conference; 2006

IAS

Background: Relatively high HIV prevalence (range=1.0-6.1%), has been documented among female sex workers (FSWs) in previous cross-sectional studies conducted in the cities of Buenos Aires, Salta, Rosario, Córdoba, Mendoza and La Plata in Argentina in 2000-02. High levels of STIs, sexual contact with foreigners and use of illegal drugs characterize this study population. In order to study the molecular epidemiology in this high-risk group, we examined the levels of genetic diversity. Methods: Twenty HIV-infected samples previously detected in these studies were genotyped. DNA was extracted from peripheral blood mononuclear cells and subjected to PCR amplification of the envelope (env) and protease/reverse transcriptase (Pro/RT). Genotype screening was conducted by heteroduplex mobility assay (HMA) of env and sequencing of Pro/RT regions. Phylogenetic and recombinant analysis of the sequences was performed. Results:  HMA was completed in 17 samples, Pro/RT sequence in 16 samples and nearly full-length sequence in 5 samples. HMA detected 6 subtype B strains, 3 of which were confirmed by Pro/RT sequence, the other 3 were BF recombinants based on either Pro/RT or full-length sequence. Subtype F was detected in 9 samples by HMA and all of them were BF recombinants by Pro/RT sequence. Four of these samples were confirmed to be BF by nearly full-length sequence. Subtype C was found in two samples by both HMA and Pro/RT. In total, 71% of the samples were found to be BF recombinants, 18% subtype B and 12% subtype C. One dually-infected individual (B and a BF recombinant) was documented. Conclusions: High levels of HIV genetic diversity were observed among FSWs in Argentina; almost three-quarters were infected with diverse unique BF recombinants. The dual infection suggests the importance of re-infection in this high risk group which represents an important source of genetic diversity among heterosexually exposed populations in Argentina.