Recent Emergence of Dengue Virus Serotype 4 in French Polynesia Results from Multiple Introductions from Other South Pacific Islands
Recent Emergence of Dengue Virus Serotype 4 in French Polynesia Results from Multiple Introductions from Other South Pacific Islands
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DOI：
10.1371/journal.pone.0029555
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发表时间：
2011-12-28
期刊：
影响因子：
3.7
通讯作者：
Aaskov, John
中科院分区：
文献类型：
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作者：
Cao-Lormeau, Van-Mai;Roche, Claudine;Aaskov, John
背景：登革热病毒（DENV）感染是数百个热带和亚热带国家的主要公共卫生问题。法属波利尼西亚（FP）经常经历在其他南太平洋岛国（SPIC）开始或连续DENV传播的流行病。2009年1月，在血清1型（DENV-1）传播十年后，FP报告了第一例DENV-4感染病例。两个月后，一种新的流行病出现了，发生在前一次DENV-4在FP中传播大约20年后。在这项研究中，我们调查了流行病学和分子特征的介绍，传播和遗传微进化的DENV-4在FP。方法/主要结果：流行病学数据表明，最近传播的DENV-4在FP开始在背风群岛，这种血清型迅速取代DENV-1在整个FP。对20世纪80年代和2009-2010年在FP收集的64株DENV-4毒株以及来自其他SPIC的一些额外毒株的包膜（E）基因核苷酸序列的系统发育分析显示，来自SPIC的DENV-4毒株分布为基因型IIa和IIb。最近的FP毒株分布成两个簇，每个簇包含来自其他但不同的SPIC的病毒，表明2009年FP中DENV-4的出现是由多次引入引起的。否则，我们观察到，几乎所有的菌株收集在SPIC在20世纪80年代表现出的E蛋白的结构域I内的氨基酸（aa）取代V287 I，和所有最近的南太平洋菌株表现出的结构域III内的T365 I取代。结论/意义：这项研究证实了循环重新出现和置换的登革病毒血清型FP。另外，我们的结果表明，在SPIC中循环的所有DENV-4菌株上都存在E蛋白上的特异性aa取代。这些取代可能获得和随后的保守可能反映了一个创始人效应与流行病学，地理，生态生物和社会的特殊性在SPIC。
Background: Infection by dengue virus (DENV) is a major public health concern in hundreds of tropical and subtropical countries. French Polynesia (FP) regularly experiences epidemics that initiate, or are consecutive to, DENV circulation in other South Pacific Island Countries (SPICs). In January 2009, after a decade of serotype 1 (DENV-1) circulation, the first cases of DENV-4 infection were reported in FP. Two months later a new epidemic emerged, occurring about 20 years after the previous circulation of DENV-4 in FP. In this study, we investigated the epidemiological and molecular characteristics of the introduction, spread and genetic microevolution of DENV-4 in FP.Methodology/Principal Findings: Epidemiological data suggested that recent transmission of DENV-4 in FP started in the Leeward Islands and this serotype quickly displaced DENV-1 throughout FP. Phylogenetic analyses of the nucleotide sequences of the envelope (E) gene of 64 DENV-4 strains collected in FP in the 1980s and in 2009-2010, and some additional strains from other SPICs showed that DENV-4 strains from the SPICs were distributed into genotypes IIa and IIb. Recent FP strains were distributed into two clusters, each comprising viruses from other but distinct SPICs, suggesting that emergence of DENV-4 in FP in 2009 resulted from multiple introductions. Otherwise, we observed that almost all strains collected in the SPICs in the 1980s exhibit an amino acid (aa) substitution V287I within domain I of the E protein, and all recent South Pacific strains exhibit a T365I substitution within domain III.Conclusions/Significance: This study confirmed the cyclic re-emergence and displacement of DENV serotypes in FP. Otherwise, our results showed that specific aa substitutions on the E protein were present on all DENV-4 strains circulating in SPICs. These substitutions probably acquired and subsequently conserved could reflect a founder effect to be associated with epidemiological, geographical, eco-biological and social specificities in SPICs.