在血吸虫病流行的湖沼型地区,由于水利灌溉事业的发展及人口呈锥形增加,在一些地方钉螺沿水系扩散,血吸虫病疫情有日益加重的趋势,个体病情虽不严重,但群体感染率仍相当高。因此,在短时间内难以消灭钉螺的重流行区,如何通过化疗尽快地控制住流行,减 In the lakes and marshes area where schistosomiasis is endemic, due to the development of irrigation and water conservancy projects and the population conical increase, in some places snails spread along the waterways, the epidemic situation of schistosomiasis has a tendency of aggravating. Although the individual’s condition is not serious, the group infection rate Very high. Therefore, in a short time it is difficult to eliminate the prevalence of snail, how to control the epidemic as soon as possible by chemotherapy