长江集城垸平垸行洪后血吸虫病疫情变化及防制对策研究

目的：探讨平垸行洪后血吸虫病疫情变化规律及防制对策。方法：前瞻性纵向观察血吸虫病疫情变化以及引洪促淤，种植意扬，改变钉螺孳生环境等防制措施的效果。结果：废垸内活螺密度呈下降趋势且未发现感染性钉螺；废垸外活螺密度变化不大且每年都出现感染性螺；滞卵在废弃垸内从事生产活动的人群血吸虫感染率较原居民上升；尽管废弃垸耕牛大幅度减少，但菜牛和羊明显增加，且3年平均感染率分别高达18．18％、13．33％；进入试区活动的人群70％以上是外迁返回居民，余为渔民、船民、鸭民及其他人员，粪检阳性率3年平均高达24．69％；洲滩污染以人、牛粪为主。结论：平垸行洪后尽管采取一些防制对策，降低了活螺密度，但外来人群的感染率和牛、羊的感染率都明显上升，废弃垸有可能形成严重的易感地带。

ENDEMIC DIVERSITY AND CONTROL STRATEGIES ON SCHISTOSOMIASIS AFTER RESERVING PLAIN FOR FLOODING IN JICHENYUAN,THE YANGTZE RIVER

Objective To explore the endemic diversity and control strategies on schistosomiasis after reserving plain for flooding.Methods Snail conditions in the embankment after reserving plain for flooding were prospectively observed and the effects of strategy of soiling plain by flooding, of planting Italian poplar and of environmental modification in snail ridden areas were evaluated.Results Density of living snails was decreased and no infected snail was found in discarded plain inside embankment. However there was no change in snail density and infected snails were still found in discarded plain outside embankment each year. Comparing present residents who still stay in discarded plain and engaged in production activities with previous residents, the infection rate of schistosomiasis has significantly increased. In discarded plain, the cattle for field plough decreased a lot. However, the cattle for meat and the goat increasde, and their infection rates also increased by 18.18% and 13.33%, respectively. More than 70% of population were returees, others were boatmen, fishermen, duckmen etc. Their stool positives rate was 24.69%. The main contamination sources were human and cattle's feces in the marshland.Conclusion Although some control strategies were implemented and the density of living snail reduced after reserving plain for flooding, infection rates of returnees, cattle and goats increased significantly. Discarded plain may become a high schistosomiasis transmission zone.