Spatial analysis of snails distribution in marshland of Jiangning county

  Objective   To explore the spatial distribution of oncomelenia snails in marshland of Jiangning county in 2000.

  Methods   The Spatial Scan Statistics and the Geographic Information System(GIS)were used to detect the spatial aggregation of Oncomelania hupensis in marshland of Jiangning County.And the semi-variogram was established to analyze the spatial auto-correlation of snails's distribution.

  Results   The GIS for snail habitats showed that the habitats in marshland mainly distributed along the Yangtze river in 2000.And the Spatial Scan Statistics detected 2 spatial clusters for alive snails and 2 for snails infected by schistosome in marshland respectively.The further analysis demonstrated that the semivariogram for the distribution of snails in spatial were spherical model, which means that the variation of snails distribution in spatial were related with the distance apart when the distance was less than 0.030 1 and the variation can be estimated by the semi-variogram.

  Conclusion   The spatial aggregations and auto-correaltion of alive snails indicated that there were some factors suitable for the survival of snails in marshland of Jiangning county.So the study on the spatial distribution of oncomelenia snails was very useful for the further research on the risk factors.