| [Objectives]To description and analysis the spatial distribution characteristics and correlativity development change rule of schistosomiasis and snail by spatial epidemiology principle and methods in Dali, exploreing influence decision factors, and to serve in schistosomiasis prevention and research work, and provides reference for the decision-making and auxiliary measures.[Materials]We collected the data of schistosomiasis and snail in Yunnan 1998～2008, Dali 2002～2008 and ErYuan 2001～2008, and Collected on-site check data in Dali and ErYuan in April 2008,and bought the TM satellite image which pictured in 2008 April 22.4 pm and covered Dali and ErYuan.and electronic map of Yunnan.[Methods] 1,Establish GIS databaseThe normalized difference vegetation index (NDVI),soil humidity,land use type and land surface temperature(LST), extracted from TM satellite image by Envi4.6.1 and Erdas9.2 soft wear, are builded grid database In GIS9.2 software. Spreadsheets formatted from data of schistosomiasis and snail by Excel and the electronic map are builded vector database In GIS9.2 software.2,Descriptive analysisThree distributions of schistosomiasis and snail in Yunan and Dali are Descriptive analyses by GIS3,Statistical analysisSpatial distribution characteristics of schistosomiasis and snail are analyzed By GIS,Spss16 and Satscan statistical analysis software. Infection rates, plow, distance to pop village with SPSS statistical analysis for crowd infection.4,Extracting snail breeding ground by Weights suitable modelUsing weights suitable model determine the most and second appropriate area for snail survival.5,Quantitative analysisThe most and second appropriate area for snail survival has been Quantitative analysised by Interpolation method based on the Sampling spots.[Results]1,The western piece of Yunan is The popularity of schistosomiasis, and Dali is one of them. The Change trend.epidemic condition in Dali is Basic consistent with Yunan province, such as Snail area, number of cases, the crowd infection etc.2,GIS database had been Established.3,Spatial analysis show that:1,The hot points is Yufeng town and the most pop villages are distribute close to the water system.2,Snail infection(X1),cow infection (x2) positively con-elated with the crowd infection(y). but the distance from water is negative. Regression model:y=3.723+0.687×X1+0.232×X2, F=39.166, P＜0.001, R2=0.471. This model can just explain 47.1% of the total variation, and factors affecting the modeling above are insufficient, so there must be some very important factors don't have been counted into consideration.4,We get vegetation index, soil moisture, land use types and surface temperature environment substitution index, and apply gold interpolation geographical statistics to simulate the distribution of snail density. The verification of the total variance can be explained 87.1% by half poor correlativity density function.5, The most and second appropriate area for snail survival have been Determined[Conclusion]1, Through the research shows that the geographic information system can more intuitive, image, dynamic display the condition of schistosomiasis popular and the distribution of snail.2, NDVI, LST, Soil moisture is strong correlation with the snail density which can be applied to correlativity monitoring in the hills type region.3,Kriging and dual suitability model of Geography information system highly reliability response to the actual distribution in a certain extent can provide some guidance for local schistosomiasis control. |
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