IMPACT OF LAND USE ON ONCOMELANIAS DISTRIBUTION IN JIANGHAN PLAIN

Schistosomiasis,aparasitic disease in tropical and subtropical areas,has serious threats to human health.Hubei Province is a serious infected area.Either its schistosomiasis condition and snail information or the harmful degree of schistosomiasis is at the top of our country.A large number of Schistosomiasis patients are distribute in Jianghan plain in this province.According to annual schistosomiasis statistics,the number of Schistosomiasis patients in Jianghan plain made up approximately 90percent of the population of Schistosomiasis patients in Hubei province.So,the difficulty of controlling Oncomelania in Jianghan plain are both general and representative in our country.In recent years,the achievements of schistosomiasis control were remarkable in Hubei province,but outbreaks still occurred.Some efforts have to be made to achieve the goal of interrupting schistosomiasis transmission.Snails serve as the only intermediate hosts, whose distribution is strongly associated with the transmission of schistosomiasis,so elimination and control of snails has become the most important and effective way to detente the distribution of schistosomiasis in Hubei province.This paper analysed the relationship of Oncomelanias density with three kinds of land use,which are prone to breed Oncomelania,including bottomland,waterways and paddy.Firstly,the remote sensing images of Landsat TM of Jianghan plain in 2009 were preprocessed using ERDAS 9.2and ENVI 4.7.On the basis of the previous few land use data,the land use change areas were extracted with vector similarity index by eCognition;then they were interpreted by visual interpretation,application of remote sensing indexes and establishment of classification rule sets.The classification result of the land use change areas was used to update the land use classification data in 2000. Then,the land use classification data in Jianghan plain in 2009were obtained.Next,this paper sorted out materials of surveying and controlling Oncomelania and calculated Oncomelanias average density at the village level.Meanwhile,the Oncomelanias distribution vectogram in 2009was drew in detail by ArcGIS software.With administrative village vectogram as base maps and with the corresponding international code as related field,and using Joins and Relates tool to connect above arranged Oncomelanias information table,the Oncomelanias database were established.The vectogram about Oncomelanias distribution and land use data were overlaid and displayed.Combined with the data from the field survey,it could draw a conclusion that Oncomelania were likely to breed on bottomland,waterways and paddy.Finally,the Oncomelanias density and the three land use ratio were analyzed by linear regression.The result showed that there was linear relationship between Oncomelanias density and the ratio of three kinds of land use. R2 of 0.857was obtained from the model.The conclusion is instructive and meaningful to estimate the Oncomelanias density by remote sensing images.Moreover,it may provide the Schistosomiasis prevention and control department with scientific reference to put forward a land use pattern of using land use reasonably and controlling Oncomelania.