title: Climate and the Timing of Imported Cases as Determinants of the Dengue Outbreak in Guangzhou, 2014: Evidence from a Mathematical Model.
abstract: As the world's fastest spreading vector-borne disease, dengue was estimated to infect more than 390 million people in 2010, a 30-fold increase in the past half century. Although considered to be a non-endemic country, mainland China had 55,114 reported dengue cases from 2005 to 2014, of which 47,056 occurred in 2014. Furthermore, 94% of the indigenous cases in this time period were reported in Guangdong Province, 83% of which were in Guangzhou City. In order to determine the possible determinants of the unprecedented outbreak in 2014, a population-based deterministic model was developed to describe dengue transmission dynamics in Guangzhou. Regional sensitivity analysis (RSA) was adopted to calibrate the model and entomological surveillance data was used to validate the mosquito submodel. Different scenarios were created to investigate the roles of the timing of an imported case, climate, vertical transmission from mosquitoes to their offspring, and intervention. The results suggested that an early imported case was the most important factor in determining the 2014 outbreak characteristics. Precipitation and temperature can also change the transmission dynamics. Extraordinary high precipitation in May and August, 2014 appears to have increased vector abundance. Considering the relatively small number of cases in 2013, the effect of vertical transmission was less important. The earlier and more frequent intervention in 2014 also appeared to be effective. If the intervention in 2014 was the same as that in 2013, the outbreak size may have been over an order of magnitude higher than the observed number of new cases in 2014.The early date of the first imported and locally transmitted case was largely responsible for the outbreak in 2014, but it was influenced by intervention, climate and vertical transmission. Early detection and response to imported cases in the spring and early summer is crucial to avoid large outbreaks in the future.
authors: Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing, People's Republic of China.|Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California, United States of America.
authors: Qu
authors: Q
authors: Cheng
authors: Department of Infectious Diseases, Guangzhou Center for Disease Control and Prevention, Guangzhou, People's Republic of China.|Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-Sen University, Guangzhou, People's Republic of China.
authors: Qinlong
authors: Q
authors: Jing
authors: Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California, United States of America.
authors: Robert C
authors: RC
authors: Spear
authors: Divisions of Biostatistics and Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, California, United States of America.
authors: John M
authors: JM
authors: Marshall
authors: Department of Infectious Diseases, Guangzhou Center for Disease Control and Prevention, Guangzhou, People's Republic of China.
authors: Zhicong
authors: Z
authors: Yang
authors: Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing, People's Republic of China.|Joint Center for Global Change Studies, Beijing, People's Republic of China.
authors: Peng
authors: P
authors: Gong
mesh_terms: D000330:Aedes / Q000502:physiology; D000818:Animals; D002681:China / Q000453:epidemiology; D002980:Climate; D003715:Dengue / Q000453:epidemiology* / Q000635:transmission; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007303:Insect Vectors / Q000502:physiology; D008297:Male; D008962:Models, Theoretical; D012621:Seasons