The changing epidemiology of dengue in China, 1990-2014: a descriptive analysis of 25 years of nationwide surveillance data.
BACKGROUND
Dengue has been a notifiable disease in China since 1 September 1989. Cases have been reported each year during the past 25 years of dramatic socio-economic changes in China, and reached a historical high in 2014. This study describes the changing epidemiology of dengue in China during this period, to identify high-risk areas and seasons and to inform dengue prevention and control activities.


METHODS
We describe the incidence and distribution of dengue in mainland China using notifiable surveillance data from 1990-2014, which includes classification of imported and indigenous cases from 2005-2014.


RESULTS
From 1990-2014, 69,321 cases of dengue including 11 deaths were reported in mainland China, equating to 2.2 cases per one million residents. The highest number was recorded in 2014 (47,056 cases). The number of provinces affected has increased, from a median of three provinces per year (range: 1 to 5 provinces) during 1990-2000 to a median of 14.5 provinces per year (range: 5 to 26 provinces) during 2001-2014. During 2005-2014, imported cases were reported almost every month and 28 provinces (90.3%) were affected. However, 99.8% of indigenous cases occurred between July and November. The regions reporting indigenous cases have expanded from the coastal provinces of southern China and provinces adjacent to Southeast Asia to the central part of China. Dengue virus serotypes 1, 2, 3, and 4 were all detected from 2009-2014.


CONCLUSIONS
In China, the area affected by dengue has expanded since 2000 and the incidence has increased steadily since 2012, for both imported and indigenous dengue. Surveillance and control strategies should be adjusted to account for these changes, and further research should explore the drivers of these trends.
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. laisj@chinacdc.cn.|Department of Geography and Environment, University of Southampton, Southampton, SO17 1BJ, UK. laisj@chinacdc.cn.
Shengjie
S
Lai
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. seenhzj@gmail.com.
Zhuojie
Z
Huang
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. zhouhang@chinacdc.cn.
Hang
H
Zhou
Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, 764 Vo Van Kiet, District 5, Ho Chi Minh City, Vietnam. katieanders99@gmail.com.|Centre for Tropical Medicine, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford, OX3 7FZ, UK. katieanders99@gmail.com.|Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia. katieanders99@gmail.com.
Katherine L
KL
Anders
Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA. taperkins@nd.edu.|Fogarty International Center, National Institutes of Health, Bethesda, MD, 20892, USA. taperkins@nd.edu.
T Alex
TA
Perkins
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. yinww@chinacdc.cn.
Wenwu
W
Yin
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. liyu1@chinacdc.cn.
Yu
Y
Li
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. mudi@chinacdc.cn.
Di
D
Mu
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. chenql@chinacdc.cn.
Qiulan
Q
Chen
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. zhangzk1@chinacdc.cn.
Zike
Z
Zhang
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. qiuyz@chinacdc.cn.
Yanzi
Y
Qiu
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. wanglp@chinacdc.cn.
Liping
L
Wang
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. zhanghl@chinacdc.cn.
Honglong
H
Zhang
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. zenglj@chinacdc.cn.
Linjia
L
Zeng
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. renxiang@chinacdc.cn.
Xiang
X
Ren
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. gengmj@chinacdc.cn.
Mengjie
M
Geng
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. lizj@chinacdc.cn.
Zhongjie
Z
Li
Department of Geography and Environment, University of Southampton, Southampton, SO17 1BJ, UK. andy.tatem@gmail.com.|Fogarty International Center, National Institutes of Health, Bethesda, MD, 20892, USA. andy.tatem@gmail.com.|Flowminder Foundation, Roslagsgatan 17 SE-11355, Stockholm, Sweden. andy.tatem@gmail.com.
Andrew J
AJ
Tatem
Fogarty International Center, National Institutes of Health, Bethesda, MD, 20892, USA. simon.i.hay@gmail.com.|Spatial Ecology and Epidemiology Group, Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK. simon.i.hay@gmail.com.
Simon I
SI
Hay
Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. yuhj@chinacdc.cn.
Hongjie
H
Yu
D000328:Adult; D002681:China / Q000453:epidemiology; D003715:Dengue / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male