Molecular characterization and phylogenetic analysis of dengue viruses imported into Taiwan during 2011-2016.

Cheng-Fen Yang,Chien-Chou Lin,Shih-Hung Lin,Tung-Chien Hsu,Shu-Fen Chang,Pei-Yun Shu,Su-Lin Yang,Tzy-Chen Wang,Chien-Ling Su,Stuart D Blacksell

doi:10.1371/journal.pntd.0006773

Cheng-Fen Yang, Chien-Chou Lin + Show 8 more

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https://doi.org/10.1371/journal.pntd.0006773

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Abstract

A total of 1,596 laboratory-confirmed imported dengue cases were identified in Taiwan during 2011–2016. Most of the imported cases arrived from Southeast Asia as well as the Indian subcontinent, the Pacific region, Latin America, Australia and Africa. Phylogenetic analyses of the complete envelope protein gene sequences from 784 imported dengue virus (DENV) isolates were conducted, and the results suggest that the DENV-1 genotype I and DENV-2 Cosmopolitan genotype comprise the predominant serotype/genotype of DENV strains circulating in Southeast Asia. The DENV-1 genotype III, DENV-3 genotype III and DENV-4 genotype I and II strains were found to be newly emerging in several Southeast Asian countries. Our results also showed that geographical restrictions of DENV-1 genotype I, DENV-1 genotype III and DENV-2 Cosmopolitan genotype are becoming blurred, indicating the extensive introductions and continuous expansions of DENV strains between nations in Southeast Asia. In this study, we present the geographic distribution and dynamic transmission of DENV strains circulating in Southeast Asian countries. In addition, we demonstrated local dengue epidemics caused by several imported DENV strains in Taiwan during 2011–2016.

Highlights

Dengue is the most prevalent mosquito-borne viral infection of humans in tropical and subtropical regions of the world [1]
The travelers were infected in 29 countries in Southeast Asia, the Indian subcontinent, the Pacific region, Latin America, Australia and Africa
Phylogenetic analyses of the envelope gene sequences of 784 imported dengue virus isolates suggest that the Dengue virus (DENV)-1 genotype I and dengue virus type 2 (DENV-2) Cosmopolitan genotype comprise the predominant serotype/genotype DENV strains circulating in Southeast

Summary

Introduction

Dengue is the most prevalent mosquito-borne viral infection of humans in tropical and subtropical regions of the world [1]. An estimated 390 million dengue infections occur annually, of which 96 million dengue infections manifest clinically [3, 4]. The DENV genome consists of a single-stranded, positive-sense RNA, which is of approximately 10,700 nucleotides and contains a long open reading frame that encodes three structural proteins (capsid [C], premembrane/membrane [prM] and envelope [E] proteins) and seven nonstructural (NS) proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) [5, 6].There are 4 genetically and antigenically distinct DENV serotypes (DENV-1 to DENV–4) that cause dengue. DENVs are transmitted to humans through the bite of an infected female Aedes mosquito [7]. Dengue disease can manifest as mild dengue fever or the more severe and potentially fatal dengue hemorrhagic fever or dengue shock syndrome [8, 9]

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