云南山区阳性螺点内感染性钉螺再现性的研究

为探索云南山区血吸虫病流行区阳性螺点内感染性钉螺再现性的规律，对１３个阳性螺点７－１１年内感染性钉螺再现情况进行了观察。通过环境抽样设框进行螺情调查，并将所捕钉螺全部解剖，检测钉螺自然感染率，每次查出感染性钉螺后均对螺点进行药物喷洒灭螺。结果１３个螺点中有１２个螺点内发现了感染性钉螺的再现，再现时间距首次灭螺后最短为１年，最长１１年，平均５年。再现次数最多的４次。结果显示阳性螺点的疫源性可保持相对稳定。在治疗传染源的同时，应主要消灭阳性螺点，灭螺范围以螺点内定点灭螺效果为佳，且对阳性螺点应长期监测。

REAPPEARANCE OF INFECTED SNAIL IN POSITIVE SNAIL SPOT IN MOUNTAINOUS REGION OF YUNNAN PROVINCE

To explore the ragularity of reappearance of infected snail in schistosomiasis mountainous endemic areas of Yunnan, 13 positive snail spots (snail spot with infected snail) were surveyed by environment sampling survey once every year for 7 to 11 years. All the snail captured were dissected and snail control measure by spraying NaCPC were made after survey. The results showed that reappearance of infected snial were found in 12 out of 13 snail positive spots. The shortest time for reappearance was 1 year after first snail control measure and the longest 11 years with an average of 5 years. In the study, the highest number of reappearaence repeated for 4 times. It has been suggested by the authors that as a source for human infection, the positive snail spots remained relatively stable and that longterm surveillance and snail control measures should be carried out in positive snail spot.