Laboratory of Molecular Virology, Oswaldo Cruz Institute, FIOCRUZ, Av. Brasil, 4365, CEP 21040-360, Rio de Janeiro, RJ, Brazil.
Infect Genet Evol. 2011 Aug;11(6):1199-207. doi: 10.1016/j.meegid.2011.04.017. Epub 2011 Apr 22.
Hepatitis B virus (HBV) has an overwhelming distribution in the world and causes important human health problems. It has infected one-third of the global population and more than 350 million people are chronic carriers. Several aspects of HBV infection confer adaptive advantages that lead to a highly efficient dissemination of the virus through different routes of transmission. HBV genotypes and subgenotypes have been associated with differences in clinical and virological characteristics, indicating that they may play a role in the virus-host relationship. In particular, a clear association between genotype A and chronic outcomes in both children and adults depending on the subgenotype involved, and between genotype C and a higher risk of complications from HBV infection, has been demonstrated. Interestingly, subgenotype A2 and genotype C are respectively likely to predominate in high-risk groups for sexual transmission and in areas where perinatal transmission is the major mode of HBV dissemination. An evolutionary approach to HBV infection, based on the principles of natural selection, may offer explanations for how modes of transmission may favor some genotypes and subgenotypes over others and, ultimately, influence HBV virulence.
乙型肝炎病毒（HBV）在世界范围内广泛分布，给人类健康带来了严重的问题。它感染了全球三分之一的人口，超过 3.5 亿人是慢性携带者。HBV 感染的几个方面赋予了适应性优势，导致病毒通过不同的传播途径高度有效地传播。HBV 基因型和亚型与临床和病毒学特征的差异相关，表明它们可能在病毒与宿主的关系中发挥作用。特别是，已经证明基因型 A 与儿童和成人的慢性结局之间存在明显的关联，这取决于所涉及的亚型，而基因型 C 与 HBV 感染并发症的风险增加有关。有趣的是，亚基因型 A2 和基因型 C 分别可能在性传播的高危人群中和围产期传播是 HBV 传播的主要模式的地区占主导地位。基于自然选择原则的 HBV 感染的进化方法可以解释传播方式如何有利于某些基因型和亚型而不是其他的，并最终影响 HBV 的毒力。
