大理市山村有血吸虫感染钉螺螺点疫源性的纵向观察

LONGITUDINAL OBSERVATION ON A SCHISTOSOME INFECTED SNAIL SPOT AS A SOURCE OF INFECTION IN A MOUNTAINOUS VILLAGE OF DALI CITY

目的： 探索阳性螺点疫源性的规律，为制定有效的防治血吸虫病措施提供科学依据。方法： 选择大理市沙里木庄村一个有血吸虫感染钉螺存在的螺点（简称阳性螺点）进行连续４ 年的纵向观察。每次均通过随机环境抽样法设框进行螺情调查，并将所捕获钉螺全部解剖，检测钉螺自然感染率。结果： ４ 年中共查螺８ 次，均查到活螺，且螺点的位置、范围相对稳定，其中有６ 次查获感染性钉螺，钉螺的平均感染率为３．９％ （８６／２ １５７）。结论： 云南山区阳性螺点的位置、范围疫源性相对稳定。因此，消灭阳性螺点是防治血吸虫病的最佳措施。

AIM: To observe longitudinally the changes in survival and infection rate of Oncomelania snails in a positive snail spot in Yunnan.METHODS: A positive snail spot in a ditch in Shalimuzhuang Village,Dali City,was continually observed on the changes in the density of snail population and natural infection rate of the snails by random environmental sampling for 8 times in 4 successive years. RESULTS: During the 8 times of snail survey,living snails were found relatively stable in the ditch,in which positive snails were obtained in 6 occasions,the average infection rate being 3.99%. CONCLUSION: The density and the positive rate of snails in the mountain region remains relatively stable as a source of human infection. Elimination of the positive snail spots is necessary for controlling schistosomiasis.