Ahmed A H, Ramzy R M
Institute of Research for Tropical Medicine, General Organization of Teaching Hospitals and Institutes, Cairo, Egypt.
J Egypt Soc Parasitol. 1999;29(3):687-96.
Population density of Lymnaea natalensis and L. columella and their natural infection with Fasciola gigantica were followed in two water bodies in Abu Rawash area, Giza Governorate over two years. L. natalensis snails were more abundant during December-February, while L. columella snails had high density during autumn. According to the snail size, we found that the reproduction of the two vector snails occurred in summer and early autumn. Fasciola was present in 0.6 and 2.0% of the examined L. natalensis and L. columella snails respectively. A high prevalence of F. gigantica in L. columella snails occurred in summer and early autumn, while their presence in L. natalensis was irregular. Naturally infected Lymnaea snails, with Fasciola, are usually of large size (> 10mm) of a given population sample. Other three types of trematode cercariae were found in both snail species; Xiphidiocercariae, Echinostomes and Amphistomes.
在两年时间里，对吉萨省阿布劳瓦什地区两个水体中的纳塔尔椎实螺和柱形椎实螺的种群密度及其感染巨片形吸虫的自然情况进行了跟踪研究。纳塔尔椎实螺在12月至2月更为常见，而柱形椎实螺在秋季密度较高。根据螺的大小，我们发现这两种作为中间宿主的螺在夏季和初秋进行繁殖。在所检查的纳塔尔椎实螺和柱形椎实螺中，分别有0.6%和2.0%感染了片形吸虫。柱形椎实螺中巨片形吸虫的高感染率出现在夏季和初秋，而在纳塔尔椎实螺中的感染情况则不规律。自然感染片形吸虫的椎实螺在给定种群样本中通常体型较大（>10毫米）。在这两种螺中还发现了其他三种类型的吸虫尾蚴；剑尾蚴、棘口吸虫和腹口吸虫。
