Riley M W, Uglem G L
School of Biological Sciences, University of Kentucky, Lexington 40506, USA.
Parasitology. 1995 May;110 ( Pt 4):429-36. doi: 10.1017/s0031182000064763.
Snails, Elimia semicarinata, infected with Proterometra macrostoma were collected monthly in 1990 and 1991 from North Elkhorn Creek near Lexington, Kentucky, and kept on a 12:12 h light-dark cycle for 2 weeks. Cercariae emerging from snails were classified into 8 strains (I-VIII) based on differences in number and distribution of spined and spineless papillae on the tail. Cercariae also had unique patterns of emergence, swimming behaviour and infectivity in 4 species of sunfish. Of 513 infected snails collected in May, 339 had pure infections with the strain frequencies (% of 339): I, 46.6; II, 7.7; III, 12.1; IV, 8.8; V, 0.6; VI, 2.7; VII, 11.8; VIII, 9.7. In the multiple infections, 159 snails shed 2 strains, 14 shed 3, and 1 snail shed 4 strains simultaneously. A comparison of sunfish and parasite populations in Kentucky, Ohio and Michigan indicated that strain frequency in P. macrostoma is regulated by the species composition of the sunfish population.
1990年和1991年期间，每月从肯塔基州列克星敦附近的北埃尔克霍恩溪采集感染了大口前殖吸虫的半嵴卷螺，并在12小时光照与12小时黑暗的循环条件下饲养2周。根据尾部分有刺和无刺乳突数量及分布的差异，将从螺体逸出的尾蚴分为8个株系（I - VIII）。尾蚴在4种太阳鱼中还具有独特的逸出模式、游动行为和感染性。5月份采集的513只感染螺中，339只为单一株系感染，各株系频率（占339只的百分比）如下：I，46.6%；II，7.7%；III，12.1%；IV，8.8%；V，0.6%；VI，2.7%；VII，11.8%；VIII，9.7%。在混合感染中，159只螺同时排出2个株系，14只排出3个株系，1只螺同时排出4个株系。对肯塔基州、俄亥俄州和密歇根州太阳鱼及寄生虫种群的比较表明，大口前殖吸虫的株系频率受太阳鱼种群物种组成的调控。
