Unravelling the history of hepatitis B virus genotypes A and D infection using a full-genome phylogenetic and phylogeographic approach

Hepatitis B virus (HBV) infection constitutes a global public health problem. In order to establish how HBV was disseminated across different geographic regions, we estimated the levels of regional clustering for genotypes D and A. We used 916 HBV-D and 493 HBV-A full-length sequences to reconstruct their global phylogeny. Phylogeographic analysis was conducted by reconstruction of ancestral states using the criterion of parsimony. The putative origin of genotype D was in North Africa/Middle East. HBV-D sequences form low levels of regional clustering for the Middle East and Southern Europe. In contrast, HBV-A sequences form two major clusters, the first including sequences mostly from sub-Saharan Africa, and the second including sequences mostly from Western and Central Europe. Conclusion: We observed considerable differences in the global dissemination patterns of HBV-D and HBV-A and different levels of monophyletic clustering in relation to the regions of prevalence of each genotype....乙型肝炎病毒（Hepatitis B virus, HBV）感染是全球性公共卫生问题。为阐明HBV在不同地理区域的传播模式，我们对D基因型（genotype D）与A基因型（genotype A）的区域聚集水平进行了量化评估。本研究共纳入916条HBV-D全长序列与493条HBV-A全长序列，以重构二者的全球系统发育树。系统地理学分析（phylogeographic analysis）采用简约准则开展祖先状态重建。分析结果显示，D基因型的推定起源地为北非/中东地区；HBV-D序列在中东与南欧区域仅呈现低水平的区域性聚集。与之形成鲜明对比的是，HBV-A序列形成两个主要聚集簇：其一的序列主要源自撒哈拉以南非洲，其二的序列主要来自西欧与中欧地区。结论：本研究观察到HBV-D与HBV-A的全球传播模式存在显著差异，且两种基因型各自流行区域的单系聚集水平亦存在明显不同。