HIV-1 Strains Identified in Brazilian Blood Donors: Significant Prevalence of B/F1 Recombinants

Abstract

In the Brazilian HIV-1 epidemic subtypes B, C, and F1 are cocirculating in the high risk population groups, and there is a high prevalence of intersubtype recombinant forms. The dynamic nature of the HIV epidemic in Brazil led us to study HIV-1 subtypes present in HIV-infected blood donations collected from 2001 to 2003. Donations from 91 seropositive donors were evaluated. Genetic subtype was obtained for 88 specimens based on sequence analysis of gag p24, pol IN, and env gp41 IDR. HIV-1 subtype B was the predominant strain present in the donor population (73.9%). A significant prevalence of intersubtype recombinants of subtypes B and F1 was found (22.7%). Subtype C (1.1%) and F1 (2.3%) were rare. None of the B/F1 recombinants is CRF28_BF or CRF29_BF. The high level of unique B/F1 recombinant strains in this population demonstrates the dynamic and complex nature of the HIV epidemic in Brazil.

Detection of distinct human immunodeficiency virus Type 1 circulating recombinant forms in Northeast Brazil

“…The subtype prevalence based on the pol, gag, and env genes was strikingly different to that described by Araujo and cols for the same population based on gag and env genes alone (91.8% B, 3.3% BF, 4.9% F) [Araujo et al, 2010]. In contrast, our subtype prevalence was similar to that found in a study that also used pol, gag, and env genes (73.9% B, 22.7% BF, 2.3% F, 1.1% C) [Brennan et al, 2007]. In fact, nine intragenic recombinants identified in this study were previously classified as pure subtypes [Araujo et al, 2010].…”

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

“…10,[12][13][14][15][16]30,31 Because we were analyzing the origin of the epidemic in South America and considering that the first detected cases of AIDS in the region occurred in Brazil and Argentina, we looked mainly for sequences derived from those two countries. In addition, the number of HIV sequences from other countries is very limited.…”

“…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.…”

Drug Resistance Mutation Profile and Accumulation Kinetics in Human Immunodeficiency Virus-Positive Individuals Infected with Subtypes B and F Failing Highly Active Antiretroviral Therapy Are Influenced by Different Viral Codon Usage Patterns

“…Brazil exhibits a heterogeneous HIV-1 subtype distribution (3,4,5,10,30) compared to that in the United States. The major virus subtype is B, accounting for 70 to 80% of infections.…”

“…Subtype C isolates are prevalent in southern states, with a relatively high proportion (30 to 60%), accounting for the main non-B isolate in this region. In summary, subtype F and its mosaic forms and CRFs are the major non-B strains circulating in Brazil (3,4,5,10,30) and South America (7,12,19,29), accounting for approximately 10 to 20% of non-B virus infections for this continent.…”