Department of Virology, Institute of Tropical Medicine (NEKKEN).
Leading Program, Graduate School of Biomedical Sciences, Nagasaki University.
Jpn J Infect Dis. 2019 Nov 21;72(6):413-419. doi: 10.7883/yoken.JJID.2019.208. Epub 2019 Aug 30.
Dengue remains a major public health problem in the Philippines. In this study, we determined the circulating dengue serotypes in the Philippines during the 2015-2017 outbreaks using a total of 678 serum samples from 537 individual dengue patients. Following an increase in the number of DENV-4 patients in recent years, we conducted a comprehensive molecular and epidemiology analysis on the DENV-4 strains isolated recently in the Philippines. Two genotypes of DENV-4 have been isolated in the Philippines since 1956: GI and GIIa. The GIIa DENV strains that were isolated in the present study were closely related to a distinct group of GIIa strains that were isolated from the Philippines in 2004. A majority of the isolates of this sub-group have been identified in the Philippines, suggesting that this lineage may have been introduced in the Philippines, and evolved to form the distinct sub-group within GIIa strains. The increase in DENV-4 activity also coincided with the appearance of the GIIa subgroup and the phasing-out of the GI lineage in the Philippines. Overall, our study demonstrates a shift in DENV-4 genotype and epidemic dynamics in a hyperendemic region, suggesting the importance of DENV genetic evolution in establishing and sustaining transmission.
登革热仍然是菲律宾的一个主要公共卫生问题。在这项研究中，我们使用来自 537 名登革热患者的总共 678 份血清样本，确定了 2015-2017 年爆发期间菲律宾的循环登革热血清型。近年来 DENV-4 患者数量增加后，我们对最近在菲律宾分离的 DENV-4 株进行了全面的分子和流行病学分析。自 1956 年以来，菲律宾已经分离出两种 DENV-4 基因型：GI 和 GIIa。本研究中分离出的 GIIa DENV 株与 2004 年从菲律宾分离出的一组独特的 GIIa 株密切相关。该亚组的大多数分离株已在菲律宾被鉴定，表明该谱系可能已在菲律宾引入，并进化形成 GIIa 株内的独特亚组。DENV-4 活动的增加也与 GIIa 亚组的出现和 GI 谱系在菲律宾的淘汰同时发生。总体而言，我们的研究表明，在一个高度流行地区，DENV-4 基因型和流行动态发生了转变，这表明 DENV 遗传进化在建立和维持传播方面的重要性。
