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Sang S.,Chinese National Institute for Communicable Disease Control and Prevention | Sang S.,U.S. Center for Disease Control and Prevention | Sang S.,Collaborating Center for Vector Surveillance and Management | Sang S.,Shandong University | And 19 more authors.
PLoS ONE | Year: 2014

Introduction: Each year there are approximately 390 million dengue infections worldwide. Weather variables have a significant impact on the transmission of Dengue Fever (DF), a mosquito borne viral disease. DF in mainland China is characterized as an imported disease. Hence it is necessary to explore the roles of imported cases, mosquito density and climate variability in dengue transmission in China. The study was to identify the relationship between dengue occurrence and possible risk factors and to develop a predicting model for dengue's control and prevention purpose. Methodology and Principal Findings: Three traditional suburbs and one district with an international airport in Guangzhou city were selected as the study areas. Autocorrelation and cross-correlation analysis were used to perform univariate analysis to identify possible risk factors, with relevant lagged effects, associated with local dengue cases. Principal component analysis (PCA) was applied to extract principal components and PCA score was used to represent the original variables to reduce multi-collinearity. Combining the univariate analysis and prior knowledge, time-series Poisson regression analysis was conducted to quantify the relationship between weather variables, Breteau Index, imported DF cases and the local dengue transmission in Guangzhou, China. The goodness-of-fit of the constructed model was determined by pseudo-R2, Akaike information criterion (AIC) and residual test. There were a total of 707 notified local DF cases from March 2006 to December 2012, with a seasonal distribution from August to November. There were a total of 65 notified imported DF cases from 20 countries, with forty-six cases (70.8%) imported from Southeast Asia. The model showed that local DF cases were positively associated with mosquito density, imported cases, temperature, precipitation, vapour pressure and minimum relative humidity, whilst being negatively associated with air pressure, with different time lags. Conclusions: Imported DF cases and mosquito density play a critical role in local DF transmission, together with weather variables. The establishment of an early warning system, using existing surveillance datasets will help to control and prevent dengue in Guangzhou, China. © 2014 Sang et al. Source

Liu Q.,Zhejiang University | Liu Q.,Collaborating Center for Vector Surveillance and Management | Liu Q.,U.S. Center for Disease Control and Prevention | Liu X.,Zhejiang University | And 24 more authors.
PLoS ONE | Year: 2012

Background: Studying the dispersal range of Anopheles sinensis is of major importance for understanding the transition from malaria control to elimination. However, no data are available regarding the dispersal range of An. sinensis in China. The aim of the present study was to study the dispersal range of An. sinensis and provide the scientific basis for the development of effective control measures for malaria elimination in China. Methodology/Principal Findings: Mark-Release-Recapture (MRR) experiments were conducted with 3000 adult wild An. sinensis in 2010 and 3000 newly emerged wild An. sinensis in 2011 in two villages of Yongcheng City in Henan Province. Marked An. sinensis were recaptured daily for ten successive days using light traps. The overall recapture rates were 0.83% (95% CI, 0.50%~1.16%) in 2010 and 1.33% (95% CI, 0.92%~1.74%) in 2011. There was no significant difference in the recapture rates of wild An. sinensis and newly emerged An. sinensis. The majority of An. sinensis were captured due east at study site I compared with most in the west at study site II. Eighty percent and 90% of the marked An. sinensis were recaptured within a radius of 100 m from the release point in study site I and II, respectively, with a maximum dispersal range of 400 m within the period of this study. Conclusions/Significance: Our results indicate that local An. sinensis may have limited dispersal ranges. Therefore, control efforts should target breeding and resting sites in proximity of the villages. © 2012 Liu et al. Source

Sang S.,Chinese National Institute for Communicable Disease Control and Prevention | Sang S.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases | Sang S.,Collaborating Center for Vector Surveillance and Management | Chen B.,Chinese National Institute for Communicable Disease Control and Prevention | And 16 more authors.
Infection, Genetics and Evolution | Year: 2015

Dengue virus and its four serotypes (DENV 1-4) infect approximately 390. million people worldwide each year, with most cases in tropical and subtropical regions. Because of repeated introduction of DENV from epidemic regions and suitable weather conditions, many regions have shifted from hypo-endemicity to hyper-endemicity over recent decades. Since the first dengue outbreak in 1978, it is crucial to understand the current situation in China over nearly 40. years. The purpose of the study was to examine whether dengue in China was endemic or not, which is essential for relevant dengue control and prevention strategy implementation in China.The study, combining epidemiological characteristics of dengue from the disease notification system, phylogenetic and phylogeographic analyses, showed that all four serotypes had been detected in Guangzhou, China, which was dominated by DENV 1-2. The Maximum Likelihood tree analytic results showed that the virus detected in Guangzhou localized in different clades, except of virus of 2002 and 2003 clustered together. There existed the mutual introductions between Guangzhou and Southeast Asia. Most of the viruses were imported from Southeast Asia and the sources of outbreaks in Guangzhou mainly originated from Thailand, Indonesia, and the Philippines.The study indicates that dengue in China still remains as an imported disease, with the possibility of localization. © 2015 Elsevier B.V. Source

Makhawi A.M.,Chinese National Institute for Communicable Disease Control and Prevention | Makhawi A.M.,Collaborating Center for Vector Surveillance and Management | Makhawi A.M.,U.S. Center for Disease Control and Prevention | Makhawi A.M.,University College of Applied Sciences | And 11 more authors.
Parasites and Vectors | Year: 2013

Background: Anopheles sinensis is a principal vector for Plasmodium vivax malaria in most parts of China. Understanding of genetic structure and genetic differentiation of the mosquito should contribute to the vector control and malaria elimination in China. Methods. The present study investigated the genetic structure of An. sinensis populations using a 729 bp fragment of mtDNA ND5 among 10 populations collected from seven provinces in China. Results: ND5 was polymorphic by single mutations within three groups of An. sinensis that were collected from 10 different geographic populations in China. Out of 140 specimens collected from 10 representative sites, 84 haplotypes and 71 variable positions were determined. The overall level of genetic differentiation of An. sinensis varied from low to moderate across China and with a F §ssub§ST§esub§ range of 0.00065 - 0.341. Genealogy analysis clustered the populations of An. sinensis into three main clusters. Each cluster shared one main haplotype. Pairwise variations within populations were higher (68.68%) than among populations (31.32%) and with high fixation index (F §ssub§ST§esub§ = 0.313). The results of the present study support population growth and expansion in the An. sinensis populations from China. Three clusters of An. sinensis populations were detected in this study with each displaying different proportion patterns over seven Chinese provinces. No correlation between genetic and geographic distance was detected in overall populations of An. sinensis (R§ssup§2§esup§ = 0.058; P = 0.301). Conclusions: The results indicate that the ND5 gene of mtDNA is highly polymorphic in An. sinensis and has moderate genetic variability in the populations of this mosquito in China. Demographic and spatial results support evidence of expansion in An. sinensis populations. © 2013 Makhawi et al.; licensee BioMed Central Ltd. Source

Guo Y.-H.,Collaborating Center for Vector Surveillance and Management | Guo Y.-H.,Chinese National Institute for Communicable Disease Control and Prevention | Lai S.-J.,U.S. Center for Disease Control and Prevention | Lai S.-J.,University of Southampton | And 7 more authors.
Acta Tropica | Year: 2016

Background: China experienced an unprecedented outbreak of dengue fever in 2014, the National Health and Family Planning Commission of the People's Republic of China (NHFPC) carried out a series of supervision work on integrated vector management (IVM), and Chinese Center for Disease Control and Prevention (China CDC) conducted a rapid detection on vector density in some areas with high dengue incidence. The goal of this study was to explain the effect of these actions, which play an important role for dengue control, and we wish to give a good example for dengue control in China, even in the world. Methods: Compare mosquito vector density with Breteau Index (BI) and dengue incidence after or along with control work vs. before. Data was entered and analyzed by Microsoft Excel 2007 and SPSS19.0. Results: Average value of BI from 22.82 in September dropped to 3.93 along with supervision and rapid detection. BI showed a significant decrease (paired sample t-test, t= 3.061, P= 0.018 < 0.05). Dengue incidence decreased gradually along with supervision and rapid detection. Conclusions: Supervised work on IVM by NHFPC and the rapid detection on dengue vector Aedes by China CDC promoted to cut down the dengue vector density, then reduced dengue incidence; both played an important role for dengue control throughout China in 2014. © 2016 Elsevier B.V. Source

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