Closely Related HIV-1 CRF01_AE Variant among Injecting Drug Users in Northern Vietnam: Evidence of HIV Spread across the Vietnam–China Border

Abstract

To investigate the nature of recent HIV outbreaks among injecting drug users (IDUs) near the Vietnam-China border, we genetically analyzed 24 HIV-positive blood specimens from 2 northern provinces of Vietnam (Lang Son and quang Ninh) adjacent to the China border, where HIV outbreaks among IDUs were first detected in late 1996. Genetic subtyping based on gag (p17) and env (C2/V3) sequences revealed that CRF01_AE is a principal strain circulating throughout Vietnam, including the provinces near the China border. The majority of CRF01_AE sequences among IDUs in Quang Ninh and Lang Son showed significant clustering with those found in nearby Pingxiang City of China's Guangxi Province, sharing a unique valine substitution 12 amino acids downstream of the V3 loop. This particular subtype E variant, uniquely found among IDUs in northern Vietnam and southeastern China, is designated E(v). The genetic diversity of CRF01_AE distributed in Quang Ninh (1.5 +/- 0.6%) and Pingxiang City (1.9 +/- 1.2%) was remarkably low, indicating the emerging nature of HIV spread in these areas. It is also noted that the genetic diversity of CRF01_AE among IDUs was consistently lower than that in persons infected sexually, suggesting that fewer closely related CRF01_AE variants were introduced into IDUs and, conversely, that multiple strains of CRF01_AE had been introduced via the sexual route. The data in the present study provide additional evidence that HIV outbreaks among IDUs in northern Vietnam were caused by the recent introduction of a highly homogeneous CRF01_AE variant (E(v)) closely related to that prevailing in nearby southern China.

Unequal Evolutionary Rates in the Human Immunodeficiency Virus Type 1 (HIV-1) Pandemic: the Evolutionary Rate of HIV-1 Slows Down When the Epidemic Rate Increases

“…By 1995, CRF01_AE was widespread among Thai IDUs (20,56), and IDU populations in other countries, such as Vietnam and Malaysia, had experienced rapid increases in CRF01_AE infections (21,43,46). In 1996 and 1997, an outbreak of CRF01_AE, genetically highly similar to the Vietnamese strain, was detected among IDUs in China (22). Today, the HIV-1 epidemic in South and Southeastern Asia is complicated not only by the interplay of injecting drug use and commercial sex work but also by the circulation of numerous HIV-1 subtypes in these risk groups, resulting in the emergence of novel intersubtype and unique recombinant strains (57,62).…”

Short Communication: Phylogenetic Characterization of HIV Type 1 CRF01_AE V3 Envelope Sequences in Pregnant Women in Northern Vietnam

“…32 This has also been observed in the context of CRF01_AE in northern Vietnam and Southern China since the 1990s to more recently. 5,6,21,30 The analysis of synonymous and nonsynonymous nucleotide changes indicated that the maternal sequences had evolved when comparing them to the older sequences from northern Vietnam. It was not possible to discern whether HIV-1 in pregnant women has evolved as a result of spreading into the general population, or is still closely related to the epidemic among intravenous drug users, a group that dominates as a source of HIV sequences in this part of the country.…”

“…However, the topology of the tree was similar to a recently reported phylogenetic analysis of the spread of HIV-1 CRF01_AE from Thailand to Southern Vietnam and then to the North. 28 The closest relationships between the sequences from northern Vietnam and a foreign source was found with the HIV-1 Pingxiang strains of HIV-1-infected individuals from the Guangxi province 5,6 in southern China, which borders with the Lang Son province in northern Vietnam.…”

“…In Vietnam, CRF01_AE has been reported to be the dominant HIV-1 genotype, even more common than in the neighboring countries. [5][6][7][8] Due to the widespread discrimination against HIV-1-infected people in Vietnam, [9][10][11] HIV-1-infected pregnant women fear being revealed. [12][13][14][15] 18 which may be a reflection of their fear.…”

“…The papers, from which the Vietnamese and Chinese sequences were obtained, were reviewed. [5][6][7][21][22][23][24][25] A maximum likelihood phylogenetic tree was inferred using PhyML v3.0 (PHYlogenetic inferences using maximum likelihood), using a GTR + G + I model with BioNJ program initial tree and an NNI search. A tree diagram was plotted with FigTree v1.1.2 by Andrew Rambaut, available at [http:/ mac.softpedia.com/get/Graphics/FigTree.shtml].…”