Laboratorio de Virología Molecular, CMBC, IVIC, Caracas, Venezuela.
J Med Virol. 2010 Nov;82(11):1829-34. doi: 10.1002/jmv.21856.
Hepatitis A virus (HAV) infection is highly prevalent in Latin America, including Venezuela. Subgenotype IA seems to circulate in an almost exclusive fashion, except in Brazil. The aim of this study was the molecular characterization of the HAV infection in Venezuela, in order to characterize the circulating strains and to analyze the presence of quasispecies in sporadic cases and an epidemic outbreak. A total of 125 (113 sera and 12 feces) samples positive for anti-HAV IgM from sporadic cases and epidemic outbreak, were submitted to hemi-nested RT-PCR for amplification of the VP1 N terminus or complete region of the HAV genome. Sequences obtained from 96 Venezuelan isolates were used for phylogenetic analysis. The quasispecies distribution was evaluated by cloning of HAV amplicons. Phylogenetic analysis of HAV sequences from Venezuela showed the exclusive circulation of subgenotype IA, but with co-circulation of two lineages, not found in other countries. The genetic variability found among Venezuelan strains was also analyzed by single-strand conformation polymorphism (SSCP). This technique allowed the detection of intra-strain variability, which was indeed related to the presence of quasispecies populations in the isolates. The quasispecies heterogeneity was higher in some isolates derived from sporadic cases compared to the one observed in the outbreak. The molecular characterization of HAV isolates from Venezuela showed the circulation of a unique subgenotype IA, but with the presence of diverse strains and quasispecies inside the viral populations.
甲型肝炎病毒(HAV)感染在拉丁美洲非常普遍,包括委内瑞拉。亚基因型 IA 似乎几乎是唯一流行的,除了在巴西。本研究的目的是对委内瑞拉的 HAV 感染进行分子特征描述,以描述循环株,并分析散发性病例和流行爆发中的准种存在情况。共对 125 份(113 份血清和 12 份粪便)来自散发性病例和流行爆发的抗 HAV IgM 阳性样本进行了半巢式 RT-PCR 检测,以扩增 HAV VP1 N 末端或全基因组。从 96 个委内瑞拉分离株中获得的序列用于系统发育分析。通过克隆 HAV 扩增子评估准种分布。委内瑞拉 HAV 序列的系统发育分析显示,仅循环亚基因型 IA,但存在两个不在其他国家发现的谱系。还通过单链构象多态性(SSCP)分析了委内瑞拉株之间的遗传变异。该技术可检测到株内变异性,实际上与分离株中准种群体的存在有关。与爆发中观察到的相比,一些来自散发性病例的分离株中的准种异质性更高。来自委内瑞拉的 HAV 分离株的分子特征描述表明,循环的独特的亚基因型 IA,但存在不同的菌株和准种在病毒种群中。