Temporal And Spatial Distribution Characteristics And Risk Mapping Of Chinese Dengue Fever In

BackgroundDengue fever caused by dengue virus is the most rapidly spreading and increasing acute infectious diseases, which was transmitted by Aedes albopictus and Ae. aegypti. As a mosquito-borne viral disease, the distribution and prevalence of dengue fever is closed related with climate factors. Most of the traditional research on dengue fever risk map only used the climate factors as variables, and their principle was that climate factors could determine the density of mosquito. With the climate changing, the areas of dengue fever distribution are expanding. Research finding, to a certain extent social、 ecological and many other factors also have an effect on the distribution of dengue fever. In this paper, the mathematical model was established to evaluate the map of dengue fever epidemics in China based on the climate factors combined with population density and GDP data.ObjectiveBased on the foundation of understanding the epidemic characteristic of dengue fever in China, the distribution areas, diffusion tread and the relationship with the imported cases, statistical analysis was performed on the spatial distribution of dengue fever to detect the high density areas. At the same time, screening the influencing factors to construct the dengue fever risk map based on climate factors, population density and GDP data in China. The results have important significance for the prevention and control of dengue fever, and provide a reference basis for the establishment of public health policy.MethodsIn this study, monthly incidence data for dengue fever at municipality level across China were analyzed for the period from 2004 to 2013.The relationships between the incidence rates of dengue fever, the involved municipalities, and the imported cases were determined. The geographic pattern of dengue fever incidence rates was examined by GIS and spatial autocorrelation analysis. Finally, spatial overlap and selects the factors by the logistic regression model to construct the dengue fever risk map in China.Results1. A total of 8293 of dengue fever cases were reported in our country from 2004 to 2013, with 4196 cases of male,4097 cases of women, and the radio of men to women is 1.024:1. People are generally susceptible to dengue fever, and the aged 20 to 50 accounted for 63.4% of all the population. Occupation distribution is wide, the unemployed, workers, farmers and business service accounted for 55%, and the medical staff is less. From the point of onset time distribution, epidemic mainly concentrated in 8 to 10 months.2. The imported cases are mainly came from Southeast Asian countries. The logarithmic values of the total number of dengue fever cases was significantly correlated with the numbers of imported cases (t=0.706, p<0.05), while the number of municipalities with imported cases was linearly correlated to the number of all municipalities that have dengue fever cases(r=0.979,p<0.05).3. Spatial analysis showed that the epidemic of dengue fever in China did not distributed randomly in the year of 2005,2010 and 2012 (Moran’s I>0.1, p<0.01), and the rest of the year (2004,2006-2009,2013) presented the characteristics of the random distribution (Moran’s I<0.05, p>0.05). The highest density occurred in areas of Pearl River Delta, Hanjiang River Delta, Dehong prefecture, and Xishuangbanna prefecture.4. Spatial overlap risk map shows, the risk areas of dengue fever epidemic at coastal are higher than inland. The risk areas including not only the dengue fever epidemic areas (Guangdong, Zhejiang, Fujian, Guangxi, Yunnan) in recent years, but also including the areas (Hainan, Shanghai, Hubei, Jiangxi), which had dengue outbroken in twentieth Century 80’s. The logistic regression model shows, high risk areas are mainly concentrated in Guangdong (Pearl River Delta, Hanjiang River Delta, Leizhou Peninsula)Zhejiang、Guangxi、Fujian、 Hainan and the border areas of Yunnan province.Conclusion1. The epidemic of dengue in China not only reflected in the increase of incidence, but also the expansion of involved municipalities. The diffusion trends are from the Southeast to the inland. The high risk persons are 20 to 50 group, and the mainly distribution of occupation are the unemployed, workers and farmers. The difference between men and women is not significantly.2. The epidemic of dengue fever in China is closely related to the imported cases, and the morbidity peak is mainly concentrated in 8 to 10 months.3. The epidemic of dengue fever presents not randomly distribution, and the high density areas are mainly distributed in the east China, the south China coast and the southwest border areas in Yunnan province.4. The indigenous dengue fever cases are related to the climate factors (average temperature, average rainfall, relative humidity, the average sunshine time), population density and GDP data. The high risk areas is basically the same to the spatial analysis, and the high risk areas occurred in areas of Pearl River Delta, Hanjiang RiverDelta, Leizhou Peninsula and the border of Yunnan province. In addition, there is also the risk of dengue fever outbreak in mainland.