2003～2007年湘江长沙段洲滩钉螺分布调查

目的全面了解湘江长沙段各洲滩钉螺的分布现状和数量变化,考核近年来的灭螺效果。方法采用系统抽样结合环境抽查的方法,对湘江长沙段洲滩进行连续5年的螺情调查。结果2003～2007年跟踪调查24个洲滩,结果有螺洲滩数分别为当年调查洲滩的77.8%、66.7%、70.8%、75.0%和62.5%,5年共查出有螺洲滩20个,占洲滩总数的83.3%。湘江长沙段各洲滩有螺框出现率、活螺率不相同,但下降趋势明显（P均〈0.01）;药物与环改灭螺相结合的效果远好于单纯的药物灭螺。结论湘江长沙段洲滩的螺情得到了较好的控制。

Distribution of Oncomelania snails in marshland of Changsha section of Xiang River,2003-2007

Objective To investigate the distribution and quantitative changes in each marshland of Cbangsba section of the Xiang River and evaluate the effectiveness of snail control in recent years. Methods A snail survey was carried out by using the systematic and environmental sampling method for 5 years. Results Twenty-four marshlands were investigated continuously from 2003 to 2007. The number of marsbland with snails accounted for 77.8%, 66.7%, 70.8%, 75. 0% and 62.5% of the each investigated year, respectively. The total number of marsblands with snails were 20 that accounted for 83.3 % of all marshlands investigated over the five years. The number of snails and the rate of living snails were different in each marsbland, but the downward trend was significant （P〈0. 01）. The combination of environment improvement and molluscicides for snail control was much more effective than only the latter. Conclusion The Oncomelania snails in the Cbangsba section of the Xiang River are well controlled.