Southgate V R, Wright C A, Laaziri H M, Knowles R J
Bull Soc Pathol Exot Filiales. 1984 Jul-Aug;77(4):409-506.
On the basis of laboratory snail infection experiments it is concluded that Planorbarius metidjensis is unimportant in the epidemiology of Schistosoma haematobium in North West Africa. 410 P. metidjensis Spain were exposed to 8 isolates of S. haematobium from Ghana, Kenya, Madagascar, Mauritius, Morocco, Tanzania, South Africa and Sudan. 50 P. metidjensis Morocco and 50 P. metidjensis Algarve were exposed to S. haematobium Morocco. All infections failed to develop to maturity. Serial sections of P. metidjensis Morocco infected with S. haematobium Morocco at 24 h, 48 h and 72 h post infection showed that 34% of the miracidia penetrated the snail epithelium, but young sporocysts were encapsulated and killed by an ameobocytic host response. Two hypotheses are postulated to explain the reports in the literature that P. metidjensis transmits S. haematobium. The dual infectivity of B. truncatus and B. africanus by S. haematobium from Guinea Bissau suggests that this isolate is probably an infraspecific hybrid with enhanced intermediate host infectivity. By analogy with work on Biomphalaria glabrata and S. mansoni, field observations of P. metidjensis transmitting S. haematobium could be explained if the snail had been previously infected with a compatible digenean, thus rendering a refractory snail into a susceptible snail. S. bovis Spain is compatible with P. metidjensis Morocco, Portugal and Spain with 14.3%, 29.2% and 73.3% of the snails respectively surviving the prepatent period becoming infected. P. metidjensis Spain is refractory to S. bovis Iran and Sudan. Thus, P. metidjensis may be important in the epidemiology of S. bovis in the Iberian Peninsula and North West Africa.
在西北非，米氏盘螺在埃及血吸虫的流行病学中并不重要。将来自西班牙的410只米氏盘螺暴露于来自加纳、肯尼亚、马达加斯加、毛里求斯、摩洛哥、坦桑尼亚、南非和苏丹的8株埃及血吸虫。将来自摩洛哥的50只米氏盘螺和来自阿尔加维的50只米氏盘螺暴露于来自摩洛哥的埃及血吸虫。所有感染均未发育至成熟阶段。对感染来自摩洛哥的埃及血吸虫24小时、48小时和72小时后的摩洛哥米氏盘螺进行连续切片观察，结果显示34%的毛蚴穿透了蜗牛上皮，但幼体胞蚴被宿主的阿米巴细胞反应包裹并杀死。针对文献中关于米氏盘螺传播埃及血吸虫的报道，提出了两种假说。来自几内亚比绍的埃及血吸虫对截形豆螺和非洲豆螺具有双重感染性，这表明该分离株可能是一种具有增强中间宿主感染性的种下杂交种。类比光滑双脐螺和曼氏血吸虫的研究，如果米氏盘螺先前感染了一种相容的复殖吸虫，从而使原本难治的蜗牛变为易感蜗牛，那么就可以解释在野外观察到米氏盘螺传播埃及血吸虫的现象。来自西班牙的牛血吸虫与来自摩洛哥、葡萄牙和西班牙的米氏盘螺相容，分别有14.3%、29.2%和73.3%的蜗牛在潜伏期存活后被感染。来自西班牙的米氏盘螺对来自伊朗和苏丹的牛血吸虫具有抗性。因此，米氏盘螺在伊比利亚半岛和西北非牛血吸虫的流行病学中可能很重要。
