Analysis of HIV Type 1 Diversity in Pregnant Women from Four Latin American and Caribbean Countries

Abstract

Worldwide, the distribution of HIV-1 subtypes and intersubtype recombinants is not homogeneous. In Latin America and the Caribbean, HIV-1 subtype B predominates. However, in the south of Brazil and in countries of the Southern cone (Argentina, Chile, Paraguay, and Uruguay) there is a different distribution of viral subtypes and intersubtype recombinants. The aim of this work was to analyze HIV-1 diversity in a cohort of pregnant women (with primarily heterosexual acquisition of the infection) who were diagnosed with HIV-1 infection during their current pregnancy and who received ARVs during pregnancy for perinatal transmission prophylaxis. Analysis of 121 partial pol sequences from subjects enrolled in Argentina, Brazil, the Bahamas, and Mexico was performed by phylogenetic and recombinant characterization. Different prevalences of subtype B were observed (100% for specimens from Mexico and the Bahamas, 61% for Brazil, and 30% for Argentina). Subtypes C and F were found, along with BC, BF, FC, and CBF recombinants in specimens from Brazilians. A high prevalence of BF recombinants was found (70%) in specimens from Argentina. The different patterns of HIV- 1 subtypes and intersubtype recombinants in South America (Argentina and Brazil) compared to those in Central and North America should be considered in the design of future HIV-1 vaccine trials.

Analysis of HIV Type 1 BF Recombinant Sequences from South America Dates the Origin of CRF12_BF to a Recombination Event in the 1970s

“…However, several studies on molecular characterization have shown that HIV-1 epidemics in South America are constituted not only by subtype B strains but also by subtype F strains, as well as recombinants between both subtype B and F. [7][8][9][10][11][12][13][14][15][16][17][18] In particular, the prevalence of BF recombinants is significantly higher than that observed for pure subtype F strains, reaching a prevalence similar to subtype B strains in some regions. 14 Considering the genetic distance between subtypes B and F, the presence of the BF recombinants in South America can only be explained by a second introduction of HIV-1 into the American Continent, independent of what occurred in the Caribbean/U.S.…”

Magnitude, Breadth, and Functional Profile of T-Cell Responses during Human Immunodeficiency Virus Primary Infection with B and BF Viral Variants

“…These reports indicate that near 50% of the HIVinfected people living in Argentina are infected either with the circulating recombinant form CRF12_BF or other BF recombinant forms related to CRF12_BF. Moreover, in other South American countries, such as Brazil and Uruguay, high prevalence of F subtype and BF recombinant variants are also found (16,32,34). These findings provide an adequate scenario to fill the gap concerning fine mapping of CTL responses in nonclade B-and C-infected patients.…”

“…To date, most reports aimed at studying CTL responses are focused on HIV clade Band C-infected patients. In Argentina, epidemiological studies revealed that early predominance of B subtype has been overshadowed by the emergence of BF recombinants (16,23,32,33,53). These reports indicate that near 50% of the HIVinfected people living in Argentina are infected either with the circulating recombinant form CRF12_BF or other BF recombinant forms related to CRF12_BF.…”

Short Communication: Evidences of Recent Decline in the Expansion Rate of the HIV Type 1 Subtype C and CRF31_BC Epidemics in Southern Brazil

“…First, strains with very similar genetic backgrounds (like subtype C and CRF31_BC) displayed very different spreading rates. Second, the prevalence of subtype C and CRF31_BC in regions that bordered southern Brazil, such as the southeast Brazilian region, [33][34][35] Argentina, 36,37 Paraguay, 38 and Uruguay, 39 remains very low (<6%), with no evidence of a rapidly increasing trend through time as has happened in the southern Brazilian region. We suggest that variations in the growth rate of HIV-1 Brazilian variants more likely reflect differences in the transmissions networks that characterized the initial spread of the subtypes rather than differences in intrinsic infectivity, although no clear relationship between risk factors for HIV-1 transmission and strain distribution have been established to date in Brazil.…”