Short communication: phylogenetic characterization of HIV type 1 CRF01_AE V3 envelope sequences in pregnant women in Northern Vietnam

Abstract

Characterization of HIV-1 strains is important for surveillance of the HIV-1 epidemic. In Vietnam HIV-1-infected pregnant women often fail to receive the care they are entitled to. Here, we analyzed phylogenetically HIV-1 env sequences from 37 HIV-1-infected pregnant women from Ha Noi (n=22) and Hai Phong (n=15), where they delivered in 2005-2007. All carried CRF01_AE in the gp120 V3 region. In 21 women CRF01_AE was also found in the reverse transcriptase gene. We compared their env gp120 V3 sequences phylogenetically in a maximum likelihood tree to those of 198 other CRF01_AE sequences in Vietnam and 229 from neighboring countries, predominantly Thailand, from the HIV-1 database. Altogether 464 sequences were analyzed. All but one of the maternal sequences colocalized with sequences from northern Vietnam. The maternal sequences had evolved the least when compared to sequences collected in Ha Noi in 2002, as shown by analysis of synonymous and nonsynonymous changes, than to other Vietnamese sequences collected earlier and/or elsewhere. Since the HIV-1 epidemic in women in Vietnam may still be underestimated, characterization of HIV-1 in pregnant women is important to observe how HIV-1 has evolved and follow its molecular epidemiology.

FIG. 1.

Phylogenetic tree of the CRF01_AE envV3 molecular epidemic in Vietnam and related countries in Southeast Asia. The phylogenetic tree shows the sequences from Thailand in green, from China in orange, from the south of Vietnam in blue, and from the north of Vietnam in purple. Sequences from other countries are shown in black. The indicated scale bar is in units of substitutions/site according to a GTR+I+G model. The maternal sequences are indicated by filled black circles.