Sequence Note: Evidence of a High Frequency of HIV-1 Subtype F Infections in a Heterosexual Population in Buenos Aires, Argentina

Abstract

We analyzed HIV-1 genetic variability, phylogenetic relationships, and association with transmission modes among 58 HIV-1-infected patients from Buenos Aires City, Argentina. The 58 strains were classified as env(gp41) HIV-1 group M subtype B (n = 34) and subgroup F1 of subtype F (n = 24). Potential recombinants combining parts of viral regions from different subtypes, B(prot)/F(env) and F(prot)/B(env), were found in two patients, and a dual infection with HIV-1 prot subtypes B and F was identified in one individual. Epidemiologic analysis of behavioral risks revealed that the frequency of infection with subtype F viruses was significantly higher (p < 0.0001) among heterosexual patients (71%) compared with homosexual patients (11%). The spread of non-B subtypes into heterosexual populations may be more common than previously thought. Our findings provide important information for monitoring the transmission of HIV-1 strains among different risk groups in Argentina as well as for vaccine development.

Comparison of the epidemiology, profile of mutations, and clinical response to antiretrovirals among subtypes B and F of the human immunodeficiency virus type 1

“…While not achieving statistical significance, some aspects already described in South America seem to occur in the population of the present study: a higher frequency of subtype F among women, in the heterosexual population and those with less schooling, as compared with the greater prevalence of subtype B in men-whohave-sex-with-men and those with more schooling (Masciotra et al 2000, Avilla et al 2002, Montano et al 2005, Rios et al 2005. In our study the difference was not so apparent, but certainly a large number of patients will show the same tendency.…”

“…In our study the difference was not so apparent, but certainly a large number of patients will show the same tendency. Some have argued that subtype F spreads more easily through heterosexual transmission (Masciotra et al 2000, Avilla et al 2002, Montano et al 2005, Rios et al 2005, using the argument that the susceptibility of Lagerhans' cells to infection by subtype B seems to be substantially lower when compared with the non-B subtypes (for example A, C, and E subtypes) (Soto-Ramirez et al 1996, Essex et al 1997. However it has recently been proved that Langerhans' cells are just as susceptible to subtype B as other non-B subtypes of HIV-1 (Solis et al 2006).…”

“…Human immunodeficiency virus type 1 (HIV-1) subtypes B and F are the most prevalent in South American countries (Masciotra et al 2000, Avilla et al 2002, Brindeiro et al 2003, Montano et al 2005, Rios et al 2005, Geretti 2006). Brazil has the largest population and the majority of cases of HIV/AIDS (a total of 433,067 cases) in the region (Brazilian Ministry of Health 2006) and subtype B is the most predominant (Brindeiro et al 2003).…”

Human Immunodeficiency Virus Type 1 Group M Protease in Cameroon: Genetic Diversity and Protease Inhibitor Mutational Features

“…For analysis of phylogenetic subtypes and the genetic diversity of the DNA sequences, viral subtypes were assigned by phylogenetic analysis of the PR gene. Our previous studies indicated that genetic variation within the 297-bp PR genes, which were sequenced from samples collected worldwide, allowed clear classification of HIV-1 strains into group M subtype A, B, C, D, F, G, H, J, and K viruses as well as group O viruses, similar to the subtype assignments based on gag or env sequences from nonrecombinant viruses (7,10,15,20,25,28,38,40). Direct analysis of the PR sequence eliminates the confusion that arises from discordant classification of viruses based on other gene regions, which may occur as a result of recombination.…”

Antiretroviral resistance in individuals presenting therapeutic failure and subtypes of the human immunodeficiency virus type 1 in the Northeast Region of Brazil

“…While 81% of the patients with subtype B were men, 43.3% of the patients with subtype F were women. This finding was also detected in Argentina (Masciotra et al 2000(Masciotra et al , Ávila et al 2002 and Chile (Rios et al 2005). There is no consensus whether this occurs due to a suspected major tropism of non-B subtypes of HIV to Langerhan's cells found in vaginal mucosa (Soto-Ramirez et al 1996) or to the late introduction of subtype F in Brazil (Bello et al 2006), concomitantly with the more recent entry of women in the Brazilian epidemic (Brito et al 2005).…”