Epidemiologic and Molecular Characterization of Human Immunodeficiency Virus Type 1 in Southern Brazil

Abstract

HIV subtype C is the most prevalent subtype in the world. Despite its recent expansion in Brazil, HIV-1C already prevails in the southernmost state of Brazil, Rio Grande do Sul. This unique HIV epidemiology has prompted us to characterize that population. Seventy-seven HIV-1-infected subjects attending the largest HIV/AIDS clinic of the state had the protease and reverse transcriptase (RT) genes of their virus subtyped and genotyped. When subtype-specific infections were plotted according to year of diagnosis, the prevalence of subtype C was shown to increase over the last 18 years of the epidemic, along with a concomitant decrease of subtype B. Comparison of subtype C-infected treated and untreated subjects revealed amino acid differences in protease and RT, especially in the RT mutation D/G123S. The overall analysis of drug resistance mutations in viruses from treated subjects has highlighted some associations between subtypes and particular mutations, such as V82A/F/T/S in protease and subtype F1 and M41L and L210W in RT and subtype B. The characterization of this important population, which is one of a few in the developing world where a large number of HIV-1C-infected subjects are under antiretroviral treatment, underscores its potential usefulness in clinical, treatment, and vaccine trials in Brazil.

Diversidade e prevalência das mutações de resistência genotípica aos antirretrovirais entre crianças infectadas pelo HIV-1

“…Brazilian studies 2-4 including children show rates from 67 to 78% of subtype B and 6 to 15% of F, results that are similar to ours (78% of subtype B and 13% of F). However, with regard to subtype C, we observed a higher rate (4.3%), a finding that has been observed in the south of Brazil, with rates ranging from 29 to 70%, 13,35,36 showing an epidemiological distinction in that region. CRF were found in 4.4% of our children (B/B-F in 2.2% and F/B in 2.2%), but it would be necessary to sequence the full gene to discard new recombinations in genomic regions.…”

The Challenge of HIV-1 Subtype Diversity

“…49 Nelfinavir resistance appears to occur primarily through L90 → M mutations in subtypes G and C and other non-B subtypes, whereas subtype B acquires either D30 → N or L90 → M nelfinavir-resistance mutations. 81,82 Overall, it appears that most antiretroviral resistance in non-B subtypes is accounted for within the current resistance databases. 83 Further studies of treated cohorts infected with non-B HIV-1 are needed to determine whether other subtype-specific pathways to resistance exist (Table 3).…”

Antiretroviral resistance and genetic diversity of human immunodeficiency virus type 1 isolates from the Federal District, Central Brazil

“…Thus it is important to monitor subtype profiles, as their distribution has local determinants, and data from one site cannot be generalized for the entire country or even for a single geographic region. HIV-1 subtype B is the most prevalent in our country, followed by subtype F1, with sporadic cases of subtypes C, D, and A (Rossini et al 2001, Gadelha et al 2003, Soares et al 2003.…”