AEGiS-15IAC: BF inter-subtype recombinants are concentrated in the Southern Cone of South America.

15th International AIDS Conference

Bangkok, Thailand - July 11-16, 2004

BF inter-subtype recombinants are concentrated in the Southern Cone of South America.

Int Conf AIDS 2004 Jul 11-16; 15:(abstract no. ThOrC1365)

Carr JK, Montano SM, Laguna-Torres VA, Olson JG, Avila MM, Sanchez J, Sanchez GI, Andrade R, Aguayo N, Birx DL, Sanchez JL
Henry M Jackson Foundation, Rockville, MD, United States

BACKGROUND: The molecular epidemiology of HIV-1 in South America is complex and has begun to be described only very recently. Unique recombinants of subtypes B and F have been found primarily in Argentina, as well as one circulating recombinant form (CRF12_BF). These have been preferentially associated with heterosexuals rather than with men who have sex with men (MSM). The following is a comprehensive examination of the epidemiology and molecular genetics of HIV-1 in 7 countries of South America.

METHODS: HIV surveillance and risk factor analyses were performed in MSM and female commercial sex workers (FCSW) in the countries of Colombia, Ecuador, Peru, Bolivia, Paraguay, Uruguay and Argentina. Representative samples from each location were selected for partial polymerase (pol) and a smaller number for full-length (FL) genome sequencing. Phylogenetic analyses were also completed.

RESULTS: Over 250 partial pol sequences were analyzed. Two-thirds of the strains were subtype B; these were more common in Andean region countries (92%) than in Southern Cone countries such as Argentina (66%) (p< 0.001). The remaining one-third of strains were BF recombinants, except for 3 subtype C samples from Argentina. In Argentina, 92% of the MSM strains were subtype B, while only 13% of the FCSW strains were subtype B (p<.001). A total of 84 nearly full genome sequences were analyzed, of which the majority were unique BF recombinants having varied, but related, structure. A new circulating recombinant strain between subtypes B and F was identified, with strains identified in Argentina (n=3), Paraguay (n=2), Bolivia (n=1) and Peru (n=1).

CONCLUSIONS: The HIV epidemic in MSM, regardless of location in these countries in South America, was overwhelmingly caused by subtype B. In FCSW located in Argentina, however, the overwhelming majority of strains were non-B: BF recombinants or subtype C. In addition, a new circulating recombinant form was found in 4 countries.

Keywords: AEGIS, HIV-1, South America, Genes, pol, HIV-1 Reverse Transcriptase, Heterosexuality, Epidemiology, Molecular, Argentina, Ecuador, Bolivia, Paraguay, Peru, Colombia, Uruguay, Humans, Male, Female, genetics

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ThOrC1365