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Purpose: To present our work in hilly areas schistosomiasis control requirements , the intermediate host of schistosomiasis in Yunnan - Yunnan Chuanya snail species targeted geographic strains of Yunnan , snail breeding situation through regular observation , research in different densities and different altitudes of the natural environment adaptability breeding cases, knowledge of changes in the interaction screw , screw movements to explore the critical control threshold indicators and snails , snail develop strategies to provide the basis to carry out the work snail . Method: 1. Choose snails live in Dali City experimental points , capturing five spin size unmated young snails , for males and females paired randomized experiments . Only density per cage 2,4,6,8,10,20,40,80,100,150,200,400,800,1000 put , each series two groups , one year after the screening of snail farming , breeding observed situation ; 2 Select Dali Cangshan 5 altitudes as the experimental point ( elevation 1980 m , 2246 m , 2635 m , 2864 m , 3001 m ) . Per 100 live snails selected randomly divided into a group , put in six groups each breeding area , breeding annually select two groups observed the situation . 3 Set the temperature and humidity instrument automatically records changes in temperature and humidity test points . Results : 1. Put snail density different reproductive rates of up to six frames , young snails snails is 13.17 times the original launch , young snails snails died only two . Followed by the four boxes , young snails snails is 4.25 times the original delivery ; 8 boxes are put snails original 3.13 times higher than in low-density high-density breeding box frame , with the increase in the number put snails , but less effective reproductive rate small , after reaching a certain stocking density stabilized at a lower level. 2 test points at different altitudes snail breeding and survival rates were 83% , 113% , 65%, 103% , 2% , 67%, 0,0.38 % ; 0,0.03 % . Decreases with increasing altitude , altitude 2635 meters at low reproductive rate , 3000 m at snail has been unable to reproduce , through statistical differences . 3 As the altitude increases, the temperature gradually decreased, insufficient effective temperature influence the survival and reproduction of snails . Conclusions : 1. Snail populations reproductive rate and snail populations density, low density snail reproduction rate than high-density, there is a certain threshold. (2) The effective snail breeding and survival rates decreased with elevation rising trend and the difference is more significant . 3 As the climate warms , the annual increase in effective temperature , suitable snail distribution range will increase.
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