三种淡水螺与广州管圆线虫相容性的实验研究

Experimental Study on Compatibility of Three Species of Freshwater Snails with Angiostrongylus cantonensis

目的比较福寿螺、中国圆田螺、铜锈环棱螺等3种食用淡水螺与广州管圆线虫的相容性。方法在相同条件下,用广州管圆线虫福建株感染3种螺,1、3、6、12及24h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3种螺感染后第1周死亡数达高峰。感染率和死亡率与螺的种类及感染时间均无相关性。虫负荷与虫密度,福寿螺感染6、12及24h均显著高于感染1h的(P值均<0.05);铜锈环棱螺,感染24h的均显著高于感染1、3、6及12h的(P值均<0.05);中国圆田螺,感染1、3、6、12及24h各组间差异均无显著性(P值均>0.05)。福寿螺感染6、12及24h的虫负荷均显著高于铜锈环棱螺和中国圆田螺(P值均<0.05)。感染6、12及24h,福寿螺及铜锈环棱螺虫密度均高于中国圆田螺(P值均<0.05)。结论3种螺对广州管圆线虫均易感并有较高的相容性,其中福寿螺的相容性较强。

Objective To compare the compatibility of three species of freshwater snails, Pomocea canaliculata, Cipangopcdudina chinensis, Bellamya aeruginosa, with Angiostrongylus cantonensis. Methods The snails were infected by the first-stage larvae of A. cantonensis under the same conditions. Twenty snails of each species were randomly sampled after exposed to the larvae for 1, 3, 6, 12, 24 hours, respectively. Each group was placed into an aquarium. Each species with same number was established as control. All the aquaria were equipped with a filter, the water temperature was kept at （24±1）℃. In the first two weeks, the number of death was recorded. Later, the snails were successively examined to record the weight and worm burden of each snail. Results Some snails were dead which mainly happened in the first week postinfection. The death rate and infection rate were not associated with exposure time and snail species. Worm burden of P. canaliculata was significantly higher than the other two species, however, the worm density of P. canaliculata and B. aeruginosa was not significantly different but higher than that of C. chinesis. The worm burden and worm density of P. canaliculata and B. aeruginosa, respectively, were significantly different among five exposure-time groups, but that of C. chinensis was not. Conclusion All the three snail species show a high compatibility with A. cantonensis. In general, the compatibility of P. canaliculata is superior to the other two species.