Molecular characterization of structural protein genes of dengue virus serotype 1 epidemic in Yunnan, Southwest China, in 2018.

Qingping Lan,Xiaodan Wang,Xiyun Shan,Qiangming Sun,Linhao Li,Yue Pan,Yun Shu,Pinghua Liu,Juan Zhang,Dehong Ma,Tingting Li,Junying Chen

doi:10.1007/s00705-020-04942-7

Abstract

A dengue virus serotype 1 (DENV-1) epidemic occurred from October to December 2018 in Xishuangbanna, Yunnan, Southwest China, neighboring Myanmar, Laos, and Vietnam. In this study, we investigated the molecular characteristics, evolution, and potential source of DENV from Xishuangbanna. The C (capsid), prM (premembrane), and E (envelope) genes of DENV isolated from 87 serum samples obtained from local patients were amplified and sequenced, and the sequences were evaluated by identification of mutations, phylogenetic and homologous recombination analysis, and secondary structure prediction. Phylogenetic analysis showed that all of the epidemic DENV strains from Xishuangbanna could be grouped in a branch with DENV-1 isolates, and were most similar to the Fujian 2005 (China, DQ193572) and Singapore 2016 (MF314188) strains. When compared with DENV-1SS (the standard strain), there were 31 non-synonymous mutations, but no obvious homologous recombination signal was found. Secondary structure prediction showed that some changes had occurred in a helical region in proteins of the MN123849 and MN123854 strains, but there were few changes in the disordered region. This study reveals the molecular characteristics of the structural genes of the Xishuangbanna epidemic strains in 2018 and provides a reference for molecular epidemiology, infection, and pathogenicity research and vaccine development.

Highlights

Dengue virus (DENV) is a ssRNA virus belonging to the family Flaviviridae that is mainly transmitted by Aedes aegypti and Aedes albopictus mosquitoes [1,2,3,4]
The results indicated that all 52 Xishuangbanna epidemic DENV strains were of the dengue virus serotype 1 (DENV-1) serotype and belonged to one branch of the tree
DENV-1 strains have been divided into six genotypes, and the results showed that these epidemic strains belonged to genotype I (Fig. 2)

Summary

Introduction

Dengue virus (DENV) is a ssRNA virus belonging to the family Flaviviridae that is mainly transmitted by Aedes aegypti and Aedes albopictus mosquitoes [1,2,3,4]. There are four different serotypes of DENV, and infection with any of the four serotypes can result in extremely severe manifestations [8,9,10]. Dengue was classified as the most important mosquito-borne viral. DENV infection usually causes a relatively mild disease called dengue fever (DF), but severe disease, including dengue shock syndrome and dengue hemorrhagic fever, can occur [6, 8]. The worldwide incidence of dengue infection has been increasing over the past decades, and about half of the world’s population is currently at risk of DENV infection. No effective treatment or vaccine is available for DF [14,15,16]

Methods

Results

Conclusion