不同密度和距离钉螺对毛蚴易感性的影响:模拟现场研究

Impact on Susceptibility to Miracidium of Schistosoma Japonicumof Oncomelania in Different Density and at Different Distance:a Simulated Field Study

目的探讨不同密度、不同距离钉螺对日本血吸虫毛蚴易感性的影响。方法在模拟现场环境下,采用20000条新鲜孵化出的毛蚴分别感染1、2、3、5 m处的钉螺,每处钉螺分为5、10、50、100只/袋4个密度组,感染4 h后带回实验室饲养,8周后解剖观察钉螺感染情况。结果在1、2、3、5 m处,5、10、50、100只/袋4个密度组钉螺感染率分别为9.86%、7.14%、6.98%和5.19%,17.33%、10.45%、8.33%和4.58%,9.55%、6.03%、4.33%和2.59%,8.06%、8%、5.34%和3.11%。结论在钉螺密度一定的情况下,钉螺受感染概率与毛蚴投放处的距离成反比;但是,未得出钉螺感染率与钉螺密度之间的线性关系,可能与密度设置有关。

Objective To investigate the impact on susceptibility to miracidium of schistosoma japonicum of Oncomelania in different density and at different distance.Methods Under a simulated setting,snails at 1,2,3 and 5 metres with a density of 5,10,50 and 100 per package were infected with 20 000 freshly hatched miracidia,and sent to laboratory 4 hours after infection.All snails were dissected 8 weeks later.Results At the sites of 1,2,3 and 5 metres,the infection rates of snails were 9.86%,7.14%,6.98% and 5.19%,17.33%,10.45%,8.33% and 4.58%,9.55%,6.03%,4.33% and 2.59% as well as 8.06%,8%,5.34% and 3.11%,respectively in density of 5,10,50 and 100 per package.Conclusion The infection rates of snails were negatively related with the distance of miracidium-thrown sites,but no linear relation between snail infection rate and snail density was obtained.