Dengue virus type 1 clade replacement in recurring homotypic outbreaks
Dengue virus type 1 clade replacement in recurring homotypic outbreaks
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DOI：
10.1186/1471-2148-13-213
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发表时间：
2013-09-28
影响因子：
3.4
通讯作者：
AbuBakar, Sazaly
中科院分区：
文献类型：
--
作者：
Teoh, Boon-Teong;Sam, Sing-Sin;AbuBakar, Sazaly
背景：在大多数登革热流行国家，反复发生的登革热疫情是周期性的。登革热病毒（DENV）感染的复发使人群易患严重登革热的风险增加。了解登革热反复暴发背后的DENV进化机制对流行预测和疾病控制具有重要意义。结果：利用一组病毒包膜(E)基因重建了马来西亚1987-2011年间分离的DENV-1的系统发育。DENV-1 E基因的系统发育分析显示，基因型病毒进化支的替换与马来西亚DENV-1主要暴发的周期性模式有关。denv - 1e基因共有9个非保守氨基酸取代；4个在域I， 3个在域II， 2个在域III。选择压力分析在全长E基因序列（1485 nt， 495个密码子）中未发现任何正向选择的密码子位点。在马来西亚分离株中共发现183个负选择位点（平均dN/dS = 0.0413）；其余312个密码子没有出现正选择和负选择。所有的病毒都被各自的患者血清交叉中和，这表明没有强有力的支持任何氨基酸替代的免疫优势。结论：DENV-1进化支替换与马来西亚DENV-1大暴发的复发有关。我们的发现与其他研究一致，即DENV-1进化支的替换是一个独立于积极选择的随机事件。
Background: Recurring dengue outbreaks occur in cyclical pattern in most endemic countries. The recurrences of dengue virus (DENV) infection predispose the population to increased risk of contracting the severe forms of dengue. Understanding the DENV evolutionary mechanism underlying the recurring dengue outbreaks has important implications for epidemic prediction and disease control.Results: We used a set of viral envelope (E) gene to reconstruct the phylogeny of DENV-1 isolated between the periods of 1987-2011 in Malaysia. Phylogenetic analysis of DENV-1 E gene revealed that genotype I virus clade replacements were associated with the cyclical pattern of major DENV-1 outbreaks in Malaysia. A total of 9 non-conservative amino acid substitutions in the DENV-1 E gene consensus were identified; 4 in domain I, 3 in domain II and 2 in domain III. Selection pressure analyses did not reveal any positively selected codon site within the full length E gene sequences (1485 nt, 495 codons). A total of 183 (mean dN/dS = 0.0413) negatively selected sites were found within the Malaysian isolates; neither positive nor negative selection was noted for the remaining 312 codons. All the viruses were cross-neutralized by the respective patient sera suggesting no strong support for immunological advantage of any of the amino acid substitutions.Conclusion: DENV-1 clade replacement is associated with recurrences of major DENV-1 outbreaks in Malaysia. Our findings are consistent with those of other studies that the DENV-1 clade replacement is a stochastic event independent of positive selection.