Department of Infectious, Parasitic and Immunomediated Disease, Istituto Superiore di Sanita', Rome, Italy.
J Med Virol. 2011 Sep;83(9):1565-70. doi: 10.1002/jmv.22154.
Intravenous drug users constitute a group at risk for hepatitis C virus (HCV) infection. Today, no data are available on the molecular epidemiology of HCV in Bulgaria despite the fact that in recent years the incidence of acute hepatitis C infection among Bulgarian intravenous drug users increased sixfold and about 2/3 of them developed a chronic infection. The aim of this study was to determine the circulation of hepatitis C genotypes among drug users and to study the evolution and transmission history of the virus by molecular clock and Bayesian methods, respectively. Sequencing of NS5B gene showed that the genotype 3a was the most prevalent type among intravenous drug users. In the Bayesian tree, the 3a subtypes grouped in one main clade with one small cluster well statistically supported. The root of the tree was dated back to the year 1836, and the main clade from Bulgaria was dated 1960. The effective number of infections remained constant until about years 1950s, growing exponentially from the 1960s to the 1990s, reaching a plateau in the years 2000. The not significant intermixing with isolates from other countries may suggest a segregated circulation of the epidemic between 1940s and 1980s. The plateau reached by the epidemic in the early 2000s may indicate the partial success of the new preventive policies adopted in Bulgaria.
静脉注射毒品使用者是丙型肝炎病毒 (HCV) 感染的高危人群。尽管近年来保加利亚静脉注射毒品使用者急性丙型肝炎感染的发病率增加了六倍，约 2/3 的人发展为慢性感染，但目前尚无关于保加利亚 HCV 分子流行病学的数据。本研究的目的是确定毒品使用者中丙型肝炎基因型的流行情况，并分别通过分子钟和贝叶斯方法研究病毒的进化和传播史。对 NS5B 基因进行测序表明，3a 型是静脉注射毒品使用者中最常见的类型。在贝叶斯树中，3a 亚型聚集在一个主要分支中，一个小分支具有统计学上的支持。树的根可以追溯到 1836 年，保加利亚的主要分支可以追溯到 1960 年。感染的有效数量保持不变，直到 20 世纪 50 年代左右，从 20 世纪 60 年代到 90 年代呈指数增长，在 21 世纪达到一个平台期。与来自其他国家的分离株的混合不明显，这可能表明在 1940 年代和 1980 年代之间，流行存在隔离循环。21 世纪初，该流行病达到平台期，这可能表明保加利亚新的预防政策取得了部分成功。
