望江县雷池江外滩位于该县东南,同马大堤外侧。长4911m,宽184～600m,总有螺面积1897056m~2。是我省血吸虫病重度易感地带之一。滩地每年5月下旬开始上水,6～8月漫滩,9月中旬开始退落。四季都有群众上滩捕鱼虾、捞猪菜和嬉水等。滩地上水前,为附近村庄耕牛的主要放牧场。螺情:据1986年春季调查,江外滩活螺平均密度为0.91只/0.11m~2,有螺框出现率24.5％,钉螺感染率0.32％,感染性钉螺密度 Wangjiang County, the Thunder River Bund in the southeast of the county, with the outer side of the Ma Di. Length 4911m, width 184 ~ 600m, total screw area 1897056m ~ 2. It is one of the most susceptible areas of schistosomiasis in our province. Beaches began in late May every year, Sheung Shui, 6 August floodplain, mid-September began to retire. Four seasons have the masses on the beach fishing shrimp, fishing pigs and leisure and so on. Beach ground water, the main pasture for nearby cattle village. According to the 1986 spring survey, the average density of living snails on the Bund was 0.91 /0.11m~2, the occurrence rate of snails was 24.5%, the infection rate of snails was 0.32%, the density of infective snails