title: High prevalence and association of HIV-1 non-B subtype with specific sexual transmission risk among antiretroviral naïve patients in Porto Alegre, RS, Brazil.
abstract: In South Brazil the circulation of two HIV-1 subtypes with different characteristics represents an important scenario for the study of the impact of HIV-1 diversity on the evolution of the HIV-1 epidemic and AIDS disease. HIV-1 B, the predominant variant in industrialized countries and HIV-1 C, the most prevalent subtype in areas with rapid epidemic growth, are implicated in most infections. We evaluated blood samples from 128 antiretroviral (ARV) naïve patients recruited at entry to the largest HIV outpatient service in Porto Alegre. Based on partial pol region sequencing, HIV-1 C was observed in 29%, HIV-1 B in 22.6% and, the recently identified CRF31_BC, in 23.4% of 128 volunteers. Other variants were HIV-1 F in 10% and other mosaics in 5.5%. In order to evaluate the association of socio-behavioral characteristics and HIV-1 subtypes, interviews and laboratory evaluation were performed at entry. Our data suggest an established epidemic of the three major variants, without any evidence of partitioning in either of the subgroups analyzed. However, anal sex practices were associated with subtype B, which could indicate a greater transmissibility of non-B variants by vaginal intercourse. This study provides baseline information for epidemiologic surveillance of the changes of the molecular characteristics of HIV-1 epidemics in this region.
authors.affiliation: Serviço de Assistência Especializada em DST/AIDS, Prefeitura Municipal de Porto Alegre, Rio Grande do Sul, Brasil. cdias.voy@terra.com.br
authors.forename: Cláudia Fontoura
authors.initials: CF
authors.lastname: Dias
authors.forename: Cynara Carvalho
authors.initials: CC
authors.lastname: Nunes
authors.forename: Isabela Osório
authors.initials: IO
authors.lastname: Freitas
authors.forename: Isabel Saraiva
authors.initials: IS
authors.lastname: Lamego
authors.forename: Ilda Maria Rodrigues de
authors.initials: IM
authors.lastname: Oliveira
authors.forename: Sabrina
authors.initials: S
authors.lastname: Gilli
authors.forename: Rosângela
authors.initials: R
authors.lastname: Rodrigues
authors.forename: Luis Fernando
authors.initials: LF
authors.lastname: Brigido
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000453:epidemiology* / Q000635:transmission* / Q000821:virology; D000293:Adolescent; D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage; D001938:Brazil / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D015658:HIV Infections / Q000188:drug therapy; D015497:HIV-1 / Q000145:classification* / Q000235:genetics; D006801:Humans; D008297:Male; D015995:Prevalence; D011995:Recombination, Genetic; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D012959:Socioeconomic Factors
chemical_list: D019380:Anti-HIV Agents