[转移帖]乙型肝炎的起源和在人类灵长类中扩散过程

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原帖由bigben发表于 2012-11-18 03:16

乙型肝炎的起源和在人类灵长类中扩散过程
　
近日，一项刊登于国际杂志Hepatology上的研究报告揭示了，乙型肝炎的传播扩散如何与人类迁徙的历史相关，这就为我们更好地理解乙肝病毒的进化提供了思路。

乙型肝炎是全球的健康问题，目前全世界有将近20亿人感染了乙肝病毒，有超过3.5亿人属于携带者。目前许多言论认为个体感染乙肝病毒和其迁徙历史有关，但是截至目前并无可靠证据证实。

这项研究就揭示了HBV（乙肝病毒）在过去40，000年中的迁移模式。研究者分析了古老人群HBV感染的扩散情况，并且分析了病毒的进化历史和人类遗传多样性的关系。他们发现HBV基因型的分配与史前现代人类的迁移有关。

研究者Gkikas Magiorkinis教授说，理解病毒来自哪里至关重要，因为它给了我们一个基本框架，用来解释病毒如何进化以至于对于人类具有危害性。理解感染性疾病的出现和传播对于我们的研究非常重要。

http://www.ibioo.com/medicine/report/13845.html

原文出处：Study reveals prehistoric journey of hepatitis B

Dating the origin and dispersal of hepatitis B virus infection in humans and primates.

Paraskevis D, Magiorkinis G, Magiorkinis E, Ho SY, Belshaw R, Allain JP, Hatzakis A.

The origin of hepatitis B virus (HBV) infection in humans and other apes remains largely unresolved.Understanding the origin of HBV is crucial because it provides a frameworkfor studying the burden, and subsequently the evolution, of HBV pathogenicity with respect to changes in human population size and life expectancy.To investigate this controversy,we examined the relationship between HBV phylogeny and genetic diversity of modern humans,investigated the timescale of global HBV dispersal andtested the hypothesis of HBV-human co-divergence. We find that the globaldistribution of HBV genotypes and subgenotypes are consistent with the major prehistoric modern human migrations.Wecalibrate the HBV molecular clock usingthe divergencetimesofdifferent indigenous human populations based on archaeological and genetic evidence,and showthatHBVjumped into humans around 33,600; 95% Higher Posterior Density: 22,000-47,100 years ago (estimated substitution rate: 2.2?10(-6) ; 95% Higher Posterior Density: 1.5-3.0?10(-6) substitutions/site/year). This coincides with the origin of modern non-African humans. Crucially, the most pronounced increase in the HBV pandemic correlates with the global population increase over the last 5,000 years. We also show that the non-human HBV clades inorang-utans and gibbonsresulted from cross-species transmission events from humansthat occurred no earlier than 6,100 years agoConclusion: Our study provides, for the first time, an estimated timescale for the HBV epidemicthat closely coincides withdates of human dispersals, supporting the hypothesis that HBV has been co-expanding and co-migrating with human populations for the last 40,000 years. (HEPATOLOGY 2012.). Copyright © 2012 American Association for the Study of Liver Diseases.

http://www.ncbi.nlm.nih.gov/pubmed/22987324