The Epidemiological Characteristics and Dynamic Transmission of Dengue in China, 2013.
BACKGROUND
There was a dengue epidemic in several regions of China in 2013. No study has explored the dynamics of dengue transmission between different geographical locations with dengue outbreaks in China. The purpose of the study is to analyze the epidemiological characteristics and to explore the dynamic transmission of dengue in China, 2013.


RESULTS
Records of dengue cases of 2013 were obtained from the China Notifiable Disease Surveillance System. Full E-gene sequences of dengue virus detected from the outbreak regions of China were download from GenBank. Geographical Information System and heatmaps were used to describe the epidemiological characteristics. Maximum Likelihood phylogenetic and Bayesian phylogeographic analyses were conducted to explore the dengue dynamic transmission. Yunnan Province and Guangdong Province had the highest imported cases in the 2013 epidemic. In the locations with local dengue transmission, most of imported cases occurred from June to November 2013 while local dengue cases developed from July to December, 2013. There were significant variations for the incidences of dengue, in terms of age distributions, among different geographic locations. However, gender differences were identified in Guangzhou, Foshan and Xishuangbanna. DENV 1-3 were detected in all locations with the disease outbreaks. Some genotypes were detected in more than one locations and more than one genotypes have been detected in several locations. The dengue viruses introduced to outbreak areas were predominantly from Southeast Asia. In Guangdong Province, the phylogeographical results indicated that dengue viruses of DENV 1 were transmitted to neighboring cities Foshan and Zhongshan from Guangzhou city, and then transmitted to Jiangmen city. The virus in DENV 3 was introduced to Guangzhou city, Guangdong Province from Xishuangbanna prefecture, Yunnan Province.


CONCLUSIONS
Repeated dengue virus introductions from Southeast Asia and subsequent domestic dengue transmission within different regions may have contributed to the dengue epidemics in China, 2013.
Clinical Epidemiology Unit, Qilu Hospital of Shandong University, Jinan, People's Republic of China.
Shaowei
S
Sang
Institute of Public Health and Management, Weifang Medical University, Weifang, People's Republic of China.
Shasha
S
Wang
State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, People's Republic of China.
Liang
L
Lu
School of Public Health, Anhui Medical University of China, People's Republic of China.|School of Public Health, The University of Adelaide, Adelaide, Australia.
Peng
P
Bi
Clinical Epidemiology Unit, Qilu Hospital of Shandong University, Jinan, People's Republic of China.
Ming
M
Lv
State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, People's Republic of China.
Qiyong
Q
Liu
D000328:Adult; D001499:Bayes Theorem; D002681:China / Q000453:epidemiology; D003198:Computer Simulation; D003715:Dengue / Q000453:epidemiology* / Q000635:transmission* / Q000821:virology; D003716:Dengue Virus / Q000145:classification; D058872:Epidemics / Q000706:statistics & numerical data; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D015233:Models, Statistical; D010802:Phylogeny