NEJM：木乃伊中发现天花病毒基因片段
2012-11-29 14:25:28 来源：NEJM 评论：0 条 我要评论
导读：法国、俄罗斯和丹麦研究人员在美国新一期《新英格兰医学杂志》上报告说，他们在俄罗斯西伯利亚地区的几具死于300多年前的冰冻“木乃伊”中检测出了天花病毒的基因片段。这一发现有助于研究者深入了解天花的演化史。天花是世界上传染性强的疾病，于1979年被消灭。目前仅有美国和俄罗斯的两个实验室保存有天花病……
法国、俄罗斯和丹麦研究人员在美国新一期《新英格兰医学杂志》上报告说，他们在俄罗斯西伯利亚地区的几具死于300多年前的冰冻“木乃伊”中检测出了天花病毒的基因片段。这一发现有助于研究者深入了解天花的演化史。
天花是世界上传染性强的疾病，于1979年被消灭。目前仅有美国和俄罗斯的两个实验室保存有天花病毒样本，早的病毒样本取自上世纪五十年代的天花患者。
2004年，法国和俄罗斯研究人员在俄罗斯西伯利亚地区的冻土中发掘出几具死于300多年前的冰冻“木乃伊”。数年后，他们对保存完好的一具“木乃伊”进行解剖，发现死者死时肺部有出血痕迹。鉴于这种症状经常在天花患者身上出现，研究人员对其开展了深入研究。
研究结果证实，这具“木乃伊”确实携有天花病毒的基因片段，但这种300多年前的天花病毒和目前存有的天花病毒类型不同。研究人员认为，这一发现有助于科研人员深入了解天花的历史，揭示天花病毒的进化速度。（来源：新华社 黄涵）
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Variola Virus in a 300-Year-Old Siberian Mummy
Smallpox which is caused by the variola virus of the Poxviridae family and the orthopoxvirus genus is among the most devastating human diseases. It may have originated and spread from Egypt the Near East or the Indus Valley 3000 to 4000 years ago and historical reports indicate epidemics in China as early as the first century A.D. and in Europe during the 6th century. By the mid-18th century smallpox was a worldwide endemic disease. It was eradicated after vaccination campaigns began more than 200 years ago.1 Variola DNA is about 186 kbp with genes distributed across conserved (central) or variable (termini) regions. Sequence analysis has revealed two main clusters: clade 1 includes variants of variola major and clade 2 includes West Africa strains and variola minor (alastrim).2 The oldest sequences that have been characterized originate from biologic samples obtained from patients during the past five to six decades. In 2004 a French and Russian team identified several archeological sites in northeastern Siberia (in Sakha Republic [Yakutia] Russian Federation). Each site consisted of frozen wooden graves buried in the permafrost and dating from the late 17th to early 18th century.3 One of these graves contained five frozen mummies (Figure 1AFIGURE 1 Grave Containing Five Mummies and Phylogenetic Analysis of Virus Detected in Tissue Samples Obtained from Mummy 2. ; and see the Supplementary Appendix available with the full text of this letter at NEJM.org). This discovery was very unusual since burial of bodies individually was the standard practice in Yakutia at that time. Analysis of the grave also suggested that the corpses were buried shortly after death.4 Biologic samples from mummy 2 were obtained for histologic and molecular investigations. Microscopical examination of pulmonary tissue showed iron inclusions suggestive of the presence of blood after a possible hemorrhagic episode (Fig. S1 in the Supplementary Appendix). On the basis of these observations the hypothesis of a sudden and lethal infection was considered one of which was variola infection. We confirmed this hypothesis by performing successful polymerase-chain-reaction (PCR) amplification of three short fragments (B7R/hemagglutinin A30L/14-kD protein and E9L/DNA polymerase) of the variola genome (PoxSib strain 718 bp of sequence information) (Fig. S2 in the Supplementary Appendix). To rule out the persistence of intact viral particles long-distance PCR analyses (E9L assay approximately 2 kb) were performed. No positive results were obtained suggesting an extensive fragmentation of the viral genome. Phylogenetic analyses confirmed that PoxSib was variola-related clustering together with 18 representative variola human sequences but distinct from contemporary clades 1 and 2 (Figure 1B). Bayesian analysis that included PoxSib extended the origin of smallpox viral strains as far back as A.D. 120 (geometric mean A.D. 928). Thus PoxSib could be a direct progenitor of modern viral strains or a member of an ancient lineage that did not cause outbreaks in the 20th century. It could be
作 者：Philippe Biagini Ph.D.
