Laboratorio de Biología de Virus, Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
Virol J. 2010 Nov 18;7:329. doi: 10.1186/1743-422X-7-329.
Dengue virus (DENV) is a member of the genus Flavivirus of the family Flaviviridae. DENV are comprised of four distinct serotypes (DENV-1 through DENV-4) and each serotype can be divided in different genotypes. Currently, there is a dramatic emergence of DENV-3 genotype III in Latin America. Nevertheless, we still have an incomplete understanding of the evolutionary forces underlying the evolution of this genotype in this region of the world. In order to gain insight into the degree of genetic variability, rates and patterns of evolution of this genotype in Venezuela and the South American region, phylogenetic analysis, based on a large number (n = 119) of envelope gene sequences from DENV-3 genotype III strains isolated in Venezuela from 2001 to 2008, were performed.
Phylogenetic analysis revealed an in situ evolution of DENV-3 genotype III following its introduction in the Latin American region, where three different genetic clusters (A to C) can be observed among the DENV-3 genotype III strains circulating in this region. Bayesian coalescent inference analyses revealed an evolutionary rate of 8.48 x 10⁻⁴ substitutions/site/year (s/s/y) for strains of cluster A, composed entirely of strains isolated in Venezuela. Amino acid substitution at position 329 of domain III of the E protein (A→V) was found in almost all E proteins from Cluster A strains.
A significant evolutionary change between DENV-3 genotype III strains that circulated in the initial years of the introduction in the continent and strains isolated in the Latin American region in recent years was observed. The presence of DENV-3 genotype III strains belonging to different clusters was observed in Venezuela, revealing several introduction events into this country. The evolutionary rate found for Cluster A strains circulating in Venezuela is similar to the others previously established for this genotype in other regions of the world. This suggests a lack of correlation among DENV genotype III substitution rate and ecological pattern of virus spread.
登革病毒（DENV）是黄病毒科黄病毒属的一员。DENV 由四个不同的血清型（DENV-1 至 DENV-4）组成，每个血清型又可以分为不同的基因型。目前，拉丁美洲出现了登革病毒 3 型 3 基因型的急剧流行。然而，我们仍然不完全了解该基因型在世界这一地区进化的背后的进化力量。为了深入了解该基因型在委内瑞拉和南美洲的遗传变异性程度、进化率和模式，对从 2001 年至 2008 年在委内瑞拉分离的登革病毒 3 型 3 基因型的大量（n = 119）包膜基因序列进行了基于系统进化的分析。
系统进化分析表明，登革病毒 3 型 3 基因型在引入拉丁美洲地区后发生了就地进化，在该地区流行的登革病毒 3 型 3 基因型中可以观察到三个不同的遗传簇（A 至 C）。贝叶斯共祖推断分析显示，完全由委内瑞拉分离株组成的簇 A 中的登革病毒 3 型 3 基因型的进化率为 8.48 x 10⁻⁴ 替换/位点/年（s/s/y）。在 E 蛋白 III 结构域 329 位的氨基酸（A→V）替换在簇 A 中几乎所有 E 蛋白中都有发现。
在该病毒在该大陆最初引入的几年中流行的登革病毒 3 型 3 基因型与近年来在拉丁美洲地区分离的病毒之间观察到了显著的进化变化。在委内瑞拉观察到了属于不同簇的登革病毒 3 型 3 基因型的存在，表明有几次该病毒传入该国。在委内瑞拉流行的簇 A 株的进化率与之前在世界其他地区为该基因型确定的进化率相似。这表明登革病毒 3 型的替换率与病毒传播的生态模式之间没有相关性。
