Re-emergence of Chikungunya virus in South-east Asia: virological evidence from Sri Lanka and Singapore
Re-emergence of Chikungunya virus in South-east Asia: virological evidence from Sri Lanka and Singapore
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DOI：
10.1099/vir.0.015743-0
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发表时间：
2010-04-01
影响因子：
3.8
通讯作者：
Ng, Lee-Ching
中科院分区：
文献类型：
--
作者：
Hapuarachchi, H. C.;Bandara, K. B. A. T.;Ng, Lee-Ching
继2005年印度洋群岛大范围爆发基孔肯雅热之后，基孔肯雅热席卷了许多南亚和东南亚国家。然而，解释基孔肯雅病毒(CHIKV)最近在亚洲地区传播和进化的分子流行病学数据仍然有限。这项研究描述了2006-2008年间在斯里兰卡和新加坡出现的CHIKV毒株的遗传特征和进化关系。在新加坡分离的病毒还包括从马尔代夫(n=1)、印度(n=2)和马来西亚(n=31)输入的病毒。所有分析的毒株都属于东部、中部和南非(ECSA)谱系，在进化上与印度毒株的亲缘关系比与印度洋岛屿毒株的亲缘关系更大。独特的遗传特征揭示了斯里兰卡和新加坡CHIKV的五个遗传亚群，它们很可能是通过多个独立的引入而出现的。基于EL基因序列的进化网络表明，印度亚种的病毒株获得了丙氨酸到Valine 226的替代(E1-A226V)，这是促成CHIKV在该地区传播和空间分布的关键进化事件。2008年，在95.7%(133/139)的分析分离株中发现了E1-A226V替换，突显出突变的CHIKV毒株在斯里兰卡、新加坡和马来西亚广泛存在。由于已知E1-A226V替换可增强白纹伊蚊传播CHIKV的能力，这一观察结果对设计媒介控制策略以对抗基孔肯雅热风险地区的病毒具有重要意义。
Chikungunya fever swept across many South and South-east Asian countries, following extensive outbreaks in the Indian Ocean Islands in 2005. However, molecular epidemiological data to explain the recent spread and evolution of Chikungunya virus (CHIKV) in the Asian region are still limited. This study describes the genetic Characteristics and evolutionary relationships of CHIKV strains that emerged in Sri Lanka and Singapore during 2006-2008. The viruses isolated in Singapore also included those imported from the Maldives (n=1), India (n=2) and Malaysia (n=31). All analysed strains belonged to the East, Central and South African (ECSA) lineage and were evolutionarily more related to Indian than to Indian Ocean Islands strains. Unique genetic characteristics revealed five genetically distinct subpopulations of CHIKV in Sri Lanka and Singapore, which were likely to have emerged through multiple, independent introductions. The evolutionary network based on El gene sequences indicated the acquisition of an alanine to valine 226 substitution (E1-A226V) by virus strains of the Indian sublineage as a key evolutionary event that contributed to the transmission and spatial distribution of CHIKV in the region. The E1-A226V substitution was found in 95.7% (133/139) of analysed isolates in 2008, highlighting the widespread establishment of mutated CHIKV strains in Sri Lanka, Singapore and Malaysia. As the E1-A226V substitution is known to enhance the transmissibility of CHIKV by Aedes albopictus mosquitoes, this observation has important implications for the design of vector control strategies to fight the virus in regions at risk of chikungunya fever.