目的　观察长江江苏段江滩感染性钉螺及其水体感染性的消长规律 ,为优化江苏省急性血吸虫感染预防方案提供依据。方法　在江苏省一江滩连续 12个月用棋盘式系统抽样法逐月采集钉螺 ,以压碎法鉴别捕获钉螺的感染性 ;以哨鼠法逐月测定滩内及周围水体的感染性。结果　在江滩上 12个月份均有感染性钉螺 ,但以 5～ 10月份钉螺阳性率最高。滩内小型水体 4～ 11月份均具有感染性 ;外江水体 5～ 9月份具有感染性。结论　在长江江苏段感染性钉螺滩块附近接触疫水全年均有感染血吸虫的可能性 ,其中以 5～ 10月份危险性最大 Objective To observe the growth and decline of infectious snails and their water infectivity in Jiangsu beach in Jiangsu Province, and to provide evidence for the prevention of acute schistosomiasis infection in Jiangsu Province. Methods The snails were collected monthly by a checkerboard system sampling method at a beach in Jiangsu Province for 12 consecutive months. The infectivity of the snails was identified by crush method. The infectivity of water bodies in and around the beach was measured monthly by sentinel mouse method. Results Infectious snails were found on the riverbanks for 12 months, but the positive rates of snails from May to October were the highest. Small beaches within the beach from April to November are infectious; River water from May to September is infectious. Conclusion The possibility of infection with schistosomiasis was observed throughout the year in the vicinity of the infected snail bank in the Jiangsu section of the Yangtze River. Among them, the highest risk was from May to October