生物谷报道：研究者说，去年Chikungunya病毒已经传播到一些新的国家，因为发现一种新品种的蚊子传播它。一种单一突变使病毒感染亚洲虎蚊子，而这种蚊子在欧洲和北美的许多国家存在。
美国得克萨斯州大学医学院的Stephen Higgs及其同事在公共科学图书馆《PLoS病原杂志》（PLoS Pathogens，生物谷注）上，发表的文章中说，这种突变增加了Chikungunya病毒永久性扩大到欧洲和美洲的可能性。他们说，随着全球变暖，平均温度持续升高，这种可能性也增加。今年病毒引起印度和意大利爆发流行。
Chikungunya是一种arbovirus病毒，多数由Aedes aegypti病毒携带。2004年在肯尼亚流行，并传播到一些印度洋岛屿。在小的联合岛屿，三分之一以上的人，266000人，受到感染，260人死亡。但是Aedes aegypti蚊子在联合岛屿上没有发现，所以研究者怀疑还有其他的动物携带病毒。已知引起联合岛屿疾病爆发的病毒出现突变，研究者对此进行检测，看病毒突变是否具有感染其他蚊子物种的能力。他们试图用遗传工程的病毒株感染多种蚊子，包括亚洲虎蚊子和Aedes albopictus。发现有非常单纯突变的病毒在虎蚊中存活。
他们写道，这项研究提出新的观点，如何人类病原的一个单纯遗传学改变会增加宿主范围，从而导致地理学分布改变。Aedes albopictus是一种广泛存在的蚊子，主要分布在欧洲和美国的城市地区，这项工作提示这些地区易于感染Chikungunya病毒。（中国公众科技网）
生物谷推荐英文原文：
PLoS Pathogens Vol. 3, No. 12, e201 doi:10.1371/journal.ppat.0030201
A Single Mutation in Chikungunya Virus Affects Vector Specificity and Epidemic Potential
Konstantin A. Tsetsarkin, Dana L. Vanlandingham, Charles E. McGee, Stephen Higgs*
1 Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
Chikungunya virus (CHIKV) is an emerging arbovirus associated with several recent large-scale epidemics. The 2005–2006 epidemic on Reunion island that resulted in approximately 266,000 human cases was associated with a strain of CHIKV with a mutation in the envelope protein gene (E1-A226V). To test the hypothesis that this mutation in the epidemic CHIKV (strain LR2006 OPY1) might influence fitness for different vector species, viral infectivity, dissemination, and transmission of CHIKV were compared in Aedes albopictus, the species implicated in the epidemic, and the recognized vector Ae. aegypti. Using viral infectious clones of the Reunion strain and a West African strain of CHIKV, into which either the E1–226 A or V mutation was engineered, we demonstrated that the E1-A226V mutation was directly responsible for a significant increase in CHIKV infectivity for Ae. albopictus, and led to more efficient viral dissemination into mosquito secondary organs and transmission to suckling mice. This mutation caused a marginal decrease in CHIKV Ae. aegypti midgut infectivity, had no effect on viral dissemination, and was associated with a slight increase in transmission by Ae. aegypti to suckling mice in competition experiments. The effect of the E1-A226V mutation on cholesterol dependence of CHIKV was also analyzed, revealing an association between cholesterol dependence and increased fitness of CHIKV in Ae. albopictus. Our observation that a single amino acid substitution can influence vector specificity provides a plausible explanation of how this mutant virus caused an epidemic in a region lacking the typical vector. This has important implications with respect to how viruses may establish a transmission cycle when introduced into a new area. Due to the widespread distribution of Ae. albopictus, this mutation increases the potential for CHIKV to permanently extend its range into Europe and the Americas.
Funding. D. L. Vanlandingham was supported in part by NIH T32 A107536. C. E. McGee was supported by a Centers for Disease Control and Prevention Fellowship Training Program in Vector-Borne Infectious Diseases TOI/CCT622892 and NIH T32 AI 07526 Training Grant in Emerging and Tropical Infectious Diseases. This study was supported in part by funding from the NIH AI R21 AI073389.
Competing interests. The authors have declared that no competing interests exist.
Editor: Edward C. Holmes, The Pennsylvania State University, United States of America
Citation: Tsetsarkin KA, Vanlandingham DL, McGee CE, Higgs S (2007) A Single Mutation in Chikungunya Virus Affects Vector Specificity and Epidemic Potential. PLoS Pathog 3(12): e201 doi:10.1371/journal.ppat.0030201
Received: September 20, 2007; Accepted: November 12, 2007; Published: December 7, 2007
Copyright: © 2007 Tsetsarkin et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
* To whom correspondence should be addressed. E-mail: sthiggs@utmb.edu
英文全文链接：
ttp://pathogens.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.ppat.0030201
