广州管圆线虫对淡水螺感染性的实验研究

目的比较研究广州管圆线虫对褐云玛瑙螺、福寿螺、中国圆田螺三种食用淡水螺的感染性。方法在相同的条件下,用广州管圆线虫I期幼虫感染三种螺,2、4、8、12及24 h后,随机抽样各20只,分别饲养于置有滤水器、水温（24±1）℃的玻璃缸内,记录感染2周内各组螺死亡数。第15天开始解剖,记录螺软体重量和感染虫数。同时设不感染螺对照组。结果三种螺感染后均有死亡,第5天死亡数达高峰。三种螺的感染率和死亡率与螺的种类及感染时间均无相关性;虫负荷与密度,福寿螺感染8、12及24 h均显著高于感染2h（P均〈0.05）,褐云玛瑙螺,感染24 h的均显著高于感染2、4、8及12 h的（P均〈0.05）,中国圆田螺,感染2、4、8、12及24 h各组间差异均无统计学意义（P均〉0.005）。褐云玛瑙螺感染8、12及24 h的虫负荷均显著高于福寿螺和中国圆田螺（P均〈0.05）。结论褐云玛瑙螺、福寿螺对广州管圆线虫易感并有较高的相容性,其中褐云玛瑙螺的相容性较强。

Experimental Study on the Infection of Freshwater Snails with Angiostrongylus cantonesis

Objective To study the infectivity of Angioslrongylus canlonensis on the freshwater snails, Achatina fulica, Bellamya oeruginosa, and Cipangopaludina chinensis. Method Snails were infected by the first-stage larvae of A.canlonensis under the same conditions. Groups of twenty snails of each species were randomly sampled after exposure to the larvae for 2,4,8,12, 24 hours. Each group of snails was kept separately in tanks equipped with water filter, and the water temperature was maintained at （24±1）℃. In the first two weeks, the number of viable snails was recorded. The weight of the snails and the worm burden of each snail was monitored starting from 2 weeks after infection. Result The death rate of snails reached a maximum at day-5 after infection, and the mortality was similar in all 3 different species of snails. Both the death rate and infection rate were not correlated with the exposure time and snail species. At 8 to 24 hours after infection, the worm burden in B.aeruginosa is significantly increased （P〈0.05）. For the A.Fulica, the worm burden is significantly increased at 24 hours after infection （P〈 0.05）. For the C.chinensis, the worm burden was similar at all time point （2-24 hours） after infection （P〈 0.05）. Both the worm burden and worm density in A.fulica were significantly higher than B.aeruginosa, and C.chinensis at 8-24 hours after infection. Conclusion Both A.fulica and B.aeruginosa are susceptible to the infection by A.cantonensis. The susceptibility of A .fulica is higher than the other species.