Emerging genetic diversity of HIV-1 in South America

Objective: Genotype determination and risk group analysis of HIV-1 infected individuals in selected regions of South America. Design: Cross-sectional convenience sampling of HIV-1-positive individuals in Peru, Ecuador, Uruguay and Paraguay from March, 1994 through September, 1998. Methods: HIV-1-positive subjects were identified through the national AIDS surveillance program in each country. A standardized questionnaire was used to obtain demographic, clinical and risk factor data on each study subject . Viral DNA was extracted from participants' peripheral blood mononuclear c ells either directly or after co-cultivation. A nested PCR was used to obta in selected fragments of the envelope genes for genotyping by the heterodup lex mobility assay (HMA). A 600 bp sequence encompassing the V3 loop was se quenced from a selection of 23 of these samples for phylogenetic analysis a nd confirmation of HMA genotype. Results: Among the 257 successfully genotyped HIV-1-positive samples, genot ype B was found in 98.3% (228/232) of those obtained from subjects in Peru, Ecuador, and Paraguay. In contrast, 56% (14/25) of the samples from Urugua y were genotype F, and the remainder were genotype B. Genotype F was detect ed for the first time in Peru (2/224) and Paraguay (1/4), and genotype A fo r the first time in Peru (1/224). Phylogenetic analysis confirmed the genot ype identified by HMA in the 23 samples sequenced. There was no detectable genetic clustering of HIV-1 within the different high-risk groups or geogra phic locations. Conclusions: These findings verify and extend the presence of several diffe rent HIV-1 genotypes in South America. (C) 2000 Lippincott Williams & Wilki ns.