Genomic epidemiological characteristics of dengue fever in Guangdong province, China from 2013 to 2017.

Bangyao Sun,Haizhou Liu,Mifang Liang,Di Liu,Huan Zhang,De Wu,Qiqi Tan,Xin Zhang,Lina Sun,Duane J Gubler

doi:10.1371/journal.pntd.0008049

Abstract

Dengue fever, a mosquito-borne viral disease in humans, has been endemic in many Southeast Asian countries. Since its first outbreak in 1978 in Foshan, Guangdong province, China, dengue has been continually epidemic in recent years in Guangdong, which raised the concern whether dengue infection is endemic in Guangdong. In this study, we performed phylogenetic, recombinant, and nucleotide variation analyses of 114 complete genome sequences of dengue virus serotypes 1–4 (DENV1-4) collected from 2013 to 2017 in 18 of 21 cities of Guangdong. Phylogenetic analyses revealed that DENV sequences did not form a single cluster, indicating that dengue fever was not endemic in Guangdong, although DENV1-4 co-circulated in Guangdong. Twenty intra-serotype recombinant isolates involving DENV1-4 were detected, but no inter-serotype recombinant events were identified in this study. Additionally, the most recombinant events were detected simultaneously in the gene NS3 of DENV1-4. Nucleotide variation analyses showed that no significant intra-serotype differences were observed, whereas more significant inter-subtype differences were discovered in non-structural genes than in structural genes. Our investigation will facilitate the understanding of the current prevalent status of dengue fever in Guangdong and contribute to designing more effective preventive and control strategies for dengue infection.

Highlights

Dengue fever was listed as a major threat to global health in 2019 by the World Health Organization, aiming to reduce half of the deaths resulting from dengue infection by 2020 (WHO, https://www.who.int/emergencies/ten-threats-to-global-health-in-2019)
In 1978, dengue fever was first reported in Guangdong province, China, and this has been continuously prevalent in Guangdong in recent years
This is responsible for the heavy burden on the control of dengue, and raises the concern about whether dengue outbreaks have become endemic in Guangdong

Summary

Introduction

Dengue fever was listed as a major threat to global health in 2019 by the World Health Organization, aiming to reduce half of the deaths resulting from dengue infection by 2020 (WHO, https://www.who.int/emergencies/ten-threats-to-global-health-in-2019). Dengue infection is a mosquito-borne disease widely distributed in tropical and subtropical countries with its clinical symptoms ranging from mild dengue fever to severe dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS)[1]. Two-fifths of the world population are under threat of dengue infection with nearly 390 million infections annually, and it is mainly distributed in Southeast Asia, Africa, Eastern Mediterranean, Americas, and Western Pacific [2]. Dengue fever is caused by dengue virus (DENV), belonging to the genus Flavivirus of family Flaviviridae. It is primarily transmitted by Aedes aegypti or Aedes albopictus mosquitoes [3] and is serologically classified into four serotypes (DENV1-4) [4, 5]. The genome of DENV is a single-strand positive-sense RNA of approximately 11 kb, consisting of a single open reading frame that encodes three structural proteins (C, M, and E) and seven nonstructural (NS) proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5), which are flanked by 5’ and 3’ untranslated regions (UTRs) [6]

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