[Development and application of geographic information system of Aedes vector in Chaozhou city, Guangdong province]

OBJECTIVE

To explore the spatial distribution character of dengue fever and the change of Aedes' population, so as to provide macroscopical decision-making evidences of prevention and supervision on dengue fever.

METHODS

(1) Collecting data on morbidity of dengue and supervision on vector's population in the corresponding period. (2) Drawing digitized map of Chaozhou in scale of 1:50,000, including elements of boundary, residential areas, road and traffic, altitude, water systems etc. (3) Measuring the latitude and longitude of center position of surveillance safes on the scene. (4) Processing spatial analysis by the ArcGIS 8.5 software.

RESULTS

Distribution of Aedes showed spatial cluster in Chaozhou, while its density was related to the distance to the watersides. The closer to the watersides, the higher the density was. Map on spatial distribution showed that although the Aedes epidemic situation changed yearly, but primarily be kept in high, middle, low regions. Cross-validation effects of the distribution maps were satisfactory.

CONCLUSION

Geographic information system was promising in analyzing data on dengue fever, and better than other routine research methods.

[Relationship of dengue fever epidemic to aedes density changed by climate factors in Guangdong Province]

In order to explore and quantify the relation between probability of dengue episode and aedes density, and climate factors, and also, to provide scientific approach for prevention and supervision of dengue fever, data on dengue fever cases, aedes vector's supervision and climate factors such as average air temperature, lowest air temperature, highest air temperature, sunlight, rainfall and relative humidity were collected and, were analyzed by correlation analysis, stepwise regression and logistic regression method. The results showed that the logistic regression equation: p (1) = 1/[1 + e-(-7.750 + 0.391 BI)], indicating that meteorology parameter correlating with breteau index(BI) were rainfall, sunlight, average air temperature, lowest average air temperature and relative humidity; by stepwise regression analysis, the regression equation: viz.: YBI = 24.800 + 0.826 X1 + 0.020 X2 - 0.418X3, X1 representing lowest average air temperature, and X2 representing rainfall and X3 representing relative humidity. It is suggested that the influence of climate factor on vector aedes density is complicated. But its primary influence factors are lowest average air temperature, rainfall and relative humidity. The primary influence factors of dengue episode are breteau index.