调查地区为塞内加尔河的下游三角洲、中游和上游。该地区人口约200万。1.螺蛳调查:目的是确定中间宿主螺类的地理分布和季节感染率。结果发现3个小泡螺亚种。盖氏小泡螺是最常见的一种,分布在下游三角洲和中游地区的池溏、灌溉沟渠、沼泽地和蓄水湖岸边,全年都能查到;塞内加尔河床中无螺。查到的3只自然感染的盖 The area under investigation is the lower Delta, the middle reaches and the upper reaches of the Senegal River. The population of the area is about 2 million. 1. Spirochaeta survey: The purpose is to determine the geographical distribution of intermediate host snails and the seasonal infection rate. As a result, 3 subfamilies were found. Gapsloma is the most common species, located in the lower reaches of the delta and the middle reaches of the ponds, irrigation ditches, swamps and impoundment shore, can be found throughout the year; Senegal non-spiral bed. Three naturally infected caps found