Distribution of human immunodeficiency virus type 1 subtypes in the state of Amazonas, Brazil, and subtype C identification

Abstract

Few studies have reported the molecular epidemiological characterization of HIV-1 in the Northern region of Brazil. The present study reports the molecular and epidemiological characterization of 31 HIV-1 isolates from blood donors from the State of Amazonas who donated blood between April 2006 and March 2007. Serum/plasma samples from all donors were screened for HIV antibodies by ELISA and the results confirmed by Western blot analysis. Genomic DNA was extracted from the buffy coat using the Super Quik-Gene-DNA Isolation kit. Nested PCR was performed on the env, gag, and pol regions of HIV-1 using the Gene Amp PCR System 9700. Sequencing reactions were performed using the inner PCR primers and the DYEnamic™ ET Dye Terminator Kit, and phylogenetic analysis was performed using the gag, pol, and env gene sequences. We collected samples from 31 blood donors who tested positive for HIV-1 in confirmatory experiments. The male:female ratio of blood donors was 3.4:1, and the mean age was 32.4 years (range: 19 to 61 years). Phylogenetic analysis showed that subtype B is the most prevalent among Northern Brazilian HIV-1-seropositive blood donors. One HIV-1 subtype C and one circulating recombinant form (CRF_BF) of HIV-1 were identified in the State of Amazonas. This is the first study showing the occurrence of a possible “homogenous” subtype C in this region of Brazil. This finding could contribute to a better characterization of the HIV-1 strains that circulate in the country. Key words: HIV-1; Subtypes; Phylogenetic analysis; Blood donors; Molecular and epidemiological characterization

HIV-1 genetic diversity and resistance to antiretroviral drugs among pregnant women in Ribeirão Preto (SP), Brazil. Cross-sectional study

“…This was consistent with other data from Brazil [12][13][14][15][16][17][18][19][20] with the exception of the southern states, where subtype C has been found to prevail. 21 To a lesser extent, presence of recombinant forms between subtypes B and F, K and between F and subtype F1 was also found.…”

Homogenous HIV-1 subtype B from the Brazilian Amazon with infrequent diverse BF1 recombinants, subtypes F1 and C among blood donors

“…Subtype B was also highly prevalent in Pará state representing 97% of 34 protease sequences of pregnant women [25] and 85% in patients failing HAART [22]. A previous study in 31 HIV-1 sequences of blood donors from Amazonas also showed the predominance of subtype B [21] and a recent study in 129 antiretroviral naïve children from Manaus showed 80.2% subtype B infections [27]. Only subtype B was identified in Boa Vista, the capital of Roraima, the northern most Brazilian state, which is only connected by road to Amazonas state, Venezuela and Guyana.…”

Sequencing of Gag/Env association with HIV genotyping resolution and HIV-related epidemiologic studies of HIV in China

“…HIV contains two long terminal repeats (LTR) at the end of its genome that include cis-regulatory sequences important for the expression of the provirus. In addition, at least nine protein-coding genes are distributed between the LTRs, including three structural proteins (Gag, Pol, and Env), two regulatory proteins (Tat and Rev), and four accessory proteins (Vif, Vpr, Vpu, and Nef) (Sides et al, 2005;Cunha et al, 2012). Whole-genome sequencing of HIV facilitates the identification of HIV subtypes, and this strategy is considered the gold standard for HIV classification (Robertson et al, 2000).…”

“…This pattern was supported by the datasets derived from sequencing of Env and Gag/Env, which revealed that Gag/Env accounted for the highest gene diversity among all markers tested. This may be explained by the relative mutation rates of Gag and Env, which encode two of the three core structural proteins of HIV (the core protein and the envelop protein, respectively) (Sides et al, 2005;Cunha et al, 2012). However, these two genes have distinct mutation rates.…”