长江如皋段江滩钉螺孳生可能性研究

STUDIES ON POSSIBILITY OF ONCOMELANIA SNAILS GROWING IN MARSHLAND OF YANGTZE RIVER IN RUGAO

目的 探讨长江江苏省如皋段江滩能否孳生钉螺及该地区的血吸虫病防治对策。方法采集长江如皋江滩及长江扬州江滩的水、土样,分析两者的理化性质;调查分析两者水文、植被、气象因子有无差异;用两者的水、土在室内饲养钉螺,比较两者的钉螺存活率及雌螺产卵率、螺卵孵化率;在如皋段及内河环境人工控制现场饲养钉螺,比较两者存活率。结果 如皋段江水的Ca^(2+)、总硬度、Mg^(2+)、氯化物和土样的SO_4^(2-)均显著高于扬州段;两者钉螺半年、1年存活率及雌螺产卵率均无显著差异;如皋段通过人工控制能孳生钉螺。结论 因长江潮汐顶托和江滩无植被钉螺难以向下游扩散,长江如皋段以东江滩无需查螺或只需用少量经费监测,以减少卫生资源的浪费。

Objective To study the possibility of snails growing in long term in the marshland a-long the Yangtze River Rugao section and to explore the schistosomiasis control strategies. Methods Samples of water and soil from the Yangtze River Rugao section and those from Yangzhou sention were collected. Physical and chemical characteristics of the two localities were investigated and compared. Hydrologic, meteorologic and vegetation factors were also investigated. Snails bred with waif r and soil collected from the two localities in the laboratory, respectively. The snail liabilities of the two localities were compared. Ratios of snail livability, snail laying eggs and eggs hatching were analyzed. Snails bred under control in the researched section and in the controlled plot along the inland river. The snail livability was observed. Results The Ca2+ , Mg2+, total rigidity and the chloride of water and SO42- of soil from researched section were significantly higher than those from the controlled section. However, there was no significant difference among the snail liabilities in half a year, in one year and the ratios of snail laying eggs of the two sections. Snails bred in the re searched section artificially. Conclusion Tide can obstruct snails spreading towards the lower reaches of the Yangtze River. Snails-inspecting may be stopped or just monitoring snails may be carried out in the east of the researched section, which will save the health resources.