Department of Clinical Sciences Luigi Sacco, Section of Infectious Diseases, University of Milan, Milano, Italy.
PLoS One. 2012;7(5):e37198. doi: 10.1371/journal.pone.0037198. Epub 2012 May 25.
Hepatitis B virus genotype D can be found in many parts of the world and is the most prevalent strain in south-eastern Europe, the Mediterranean Basin, the Middle East, and the Indian sub-continent. The epidemiological history of the D genotype and its subgenotypes is still obscure because of the scarcity of appropriate studies. We retrieved from public databases a total of 312 gene P sequences of HBV genotype D isolated in various countries throughout the world, and reconstructed the spatio-temporal evolutionary dynamics of the HBV-D epidemic using a bayesian framework.The phylogeographical analysis showed that India had the highest posterior probability of being the location of the tree root, whereas central Asia was the most probable location of the common ancestor of subgenotypes D1-D3. HBV-D5 (identified in native Indian populations) diverged from the tree root earlier than D1-D3. The time of the most recent common ancestor (tMRCA) of the tree root was 128 years ago, which suggests that the common ancestor of the currently circulating subgenotypes existed in the second half of the XIX century. The mean tMRCA of subgenotypes D1-D3 was between the 1940s and the 1950-60s. On the basis of our phylogeographic reconstruction, it seems that HBV-D reached the Mediterranean area in the middle of the XX century by means of at least two routes: the first pathway (mainly due to the spread of subgenotype D1) crossing the Middle East and reaching north Africa and the eastern Mediterranean, and the second pathway (closely associated with D2) that crossed the former Soviet Union and reached eastern Europe and the Mediterranean through Albania. We hypothesise that the main route of dispersion of genotype D was the unsafe use of injections and drug addiction.
乙型肝炎病毒基因型 D 可在世界许多地区发现，是东南欧、地中海盆地、中东和印度次大陆最流行的毒株。由于缺乏适当的研究，D 基因型及其亚型的流行病学历史仍然不清楚。我们从公共数据库中总共检索到 312 个乙型肝炎病毒基因型 D 的基因 P 序列，这些序列是在世界各地不同国家分离得到的，并使用贝叶斯框架重建了乙型肝炎病毒-D 流行的时空进化动态。系统发育地理分析表明，印度是树根部最有可能的所在地，而中亚是 D1-D3 亚型共同祖先最有可能的所在地。HBV-D5（在印度本土人群中发现）比 D1-D3 更早从树根部分化出来。树根部最近共同祖先（tMRCA）的时间是 128 年前，这表明目前流行的亚群的共同祖先存在于 19 世纪下半叶。D1-D3 亚群的平均 tMRCA 在 20 世纪 40 年代至 50-60 年代之间。基于我们的系统发育重建，乙型肝炎病毒-D 似乎通过至少两条途径在 20 世纪中叶到达地中海地区：第一条途径（主要是由于 D1 亚群的传播）穿过中东，到达北非和地中海东部；第二条途径（与 D2 密切相关）穿过前苏联，通过阿尔巴尼亚到达东欧和地中海。我们假设基因型 D 的主要传播途径是不安全的注射和药物滥用。
