Increasing airline travel may facilitate co-circulation of multiple dengue virus serotypes in Asia.

Huaiyu Tian,Bing Xu,Bo Xu,Nuno Rodrigues Faria,Jing Yang,Zhe Sun,Bernard Cazelles,Qiqi Yang,Shanqian Huang,Oliver G Pybus

doi:10.1371/journal.pntd.0005694

Abstract

The incidence of dengue has grown dramatically in recent decades worldwide, especially in Southeast Asia and the Americas with substantial transmission in 2014–2015. Yet the mechanisms underlying the spatio-temporal circulation of dengue virus (DENV) serotypes at large geographical scales remain elusive. Here we investigate the co-circulation in Asia of DENV serotypes 1–3 from 1956 to 2015, using a statistical framework that jointly estimates migration history and quantifies potential predictors of viral spatial diffusion, including socio-economic, air transportation and maritime mobility data. We find that the spread of DENV-1, -2 and -3 lineages in Asia is significantly associated with air traffic. Our analyses suggest the network centrality of air traffic hubs such as Thailand and India contribute to seeding dengue epidemics, whilst China, Cambodia, Indonesia, and Singapore may establish viral diffusion links with multiple countries in Asia. Phylogeographic reconstructions help to explain how growing air transportation networks could influence the dynamics of DENV circulation.

Highlights

Dengue virus (DENV) is a growing threat to public health, with nearly 390 million infections every year worldwide, of which ~96 million are symptomatic [1,2]
We find that the spread of DENV-1, -2 and -3 lineages in Asia is significantly associated with air traffic
The years 2014 and 2015 were characterized by large dengue outbreaks worldwide, which are a threat to public health, especially in Asian countries

Summary

Introduction

Dengue virus (DENV) is a growing threat to public health, with nearly 390 million infections every year worldwide, of which ~96 million are symptomatic [1,2]. An estimated 2.5 billion people are at risk of dengue infection [3]. Dengue is regarded as the world’s most important mosquito-borne viral disease and is endemic in more than 100 countries [4], with most disease burden limited to tropical and subtropical regions [5]. In 2014 an outbreak of dengue occurred in Japan for the first time in over 70 years. This occurred despite the country’s temperate climate, and viral phylogenetic analysis suggests that the Japanese outbreak resulted from international travel from Southeast Asia [6]. In 2014, a dengue outbreak affected several Asian countries, including China, Thailand, Vietnam and Japan [7,8]

Methods

Results

Discussion

Conclusion