通过对江苏省１９８１年以来逐年达到血吸虫病传播阻断标准（简称“达标”）的２９个县（市、区）钉螺消长情况的纵向监测研究，进一步揭示了残存钉螺的分布及消长特点，同时对钉螺监测方法也进行了探讨。结果表明：５５．１７％的县（市、区）在“达标”后出现钉螺，并且残存钉螺大多（７７．３７％）出现在“达标”后５年内，最长间隔达１２年仍可出现钉螺；“达标”后钉螺消长符合残存螺点螺口消长规律；在历史有螺环境“复现”的螺点多呈低密度小面积，一般与灭螺质量有关，而“新发现”螺点相对面积较大，密度较高，甚至还可出现感染性钉螺，常与钉螺扩散、查漏或漏查有关；螺情监测表明查灭螺质量是出现残存钉螺的主要因素，邻近扩散和外来输入也不容忽视；钉螺监测方法研究显示：“定点查”检出率明显高于“普查”和“轮查”。建议采用不同方法组合进行监测查螺，特别在“达标”后近５年要加强历史有螺环境的监测，远期监测则侧重外来输入。 Through the longitudinal monitoring study on the growth and development of Oncomelania snails in 29 counties (cities and districts) in Jiangsu Province, which reached the standard of blocking transmission of schistosomiasis year by year since 1981, the distribution and growth characteristics of the remaining snails were further revealed. Oncomelania monitoring methods are also discussed. The results showed that 55.17% of the counties (cities and districts) were found to be oncomelania after “reaching the standard”, and most of the remaining snails (77.37%) appeared within 5 years after “reaching the standard”, up to a maximum of 12 years On the history of snail environment, the “reappearance” of the snails is mostly of low density and small area, which is generally related to the quality of molluscum, while the “newly discovered” snail point Relatively large area, high density, and even infectious snails may occur, often associated with snail diffusion, leak detection or omission; snail monitoring showed that check the snail quality is the main factor remaining remnant snails, adjacent to proliferation and foreign input Also can not be ignored; snail monitoring methods research shows: “sentinel” detection rate was significantly higher than the “census” and “round of investigation.” It is suggested that different combinations of methods be used for surveillance of snail surveys, especially in the past five years after the target of “standardization” has been strengthened, while long-term monitoring has focused on external inputs.