CEDIVE, Fac. Cs. Veterinarias, Universidad Nacional de La Plata, Alvear 803, (7130), Chascomús, Buenos Aires, Argentina.
Parasitol Res. 2012 Nov;111(5):2011-6. doi: 10.1007/s00436-012-3049-9. Epub 2012 Aug 4.
Allopatric and sympatric infections of Lymnaea neotropica and Lymnaea viatrix var. ventricosa with Argentinean and French isolates of Fasciola hepatica were carried out to determine the capacity of these snails to produce metacercariae and to verify if this capacity changed with snail generation. The same process was also made with a French population of Galba truncatula known to be highly susceptible to French isolates of the parasite. In each lymnaeid species separately considered, the survival rate at day 30 post-exposure and prevalence of F. hepatica infection in the group infected with Argentinean miracidia were significantly greater than those recorded in the corresponding French one. Compared to infected G. truncatula, both South American lymnaeids had longer patent periods and produced a higher number of metacercariae. The highest infections were noted with L. v. ventricosa. In the three snail species, metacercarial production was more important with the Argentinean isolate of miracidia than with the French one. If three successive generations of L. v. ventricosa are exposed to the same French isolate of miracidia, cercarial production significantly increased from parents to the F2 generation, while the other characteristics of infection only showed insignificant variations. L. neotropica and L. v. ventricosa are better intermediate hosts for French F. hepatica than local G. truncatula. The numerical increase of shed cercariae in the F1 and F2 generations of L. v. ventricosa demonstrates a rapid adaptation of this species to the French isolate of the parasite.
对新热带椎实螺和越中巨腔螺的同域和异域感染以及阿根廷和法国的肝片吸虫进行了研究，以确定这些蜗牛产生肝片形吸虫囊蚴的能力，并验证这种能力是否随蜗牛代次而变化。同样的过程也在法国高体蜾蠃种群中进行，该种群已知对法国寄生虫分离株高度敏感。在单独考虑的每种椎实螺中，暴露后第 30 天的存活率和感染阿根廷尾蚴的组中肝片吸虫感染的流行率明显高于相应的法国组。与感染的高体蜾蠃相比，这两种南美洲椎实螺的发病期更长，产生的囊蚴数量更多。感染的椎实螺以 L. v. ventricosa 最为严重。在这三种蜗牛中，与法国尾蚴分离株相比，阿根廷尾蚴分离株产生的囊蚴更多。如果连续三代的 L. v. ventricosa 暴露于相同的法国尾蚴分离株，从亲代到 F2 代，尾蚴的产生显著增加，而感染的其他特征仅显示出无意义的变化。与当地的高体蜾蠃相比，新热带椎实螺和越中巨腔螺是法国肝片吸虫的更好的中间宿主。在 L. v. ventricosa 的 F1 和 F2 代中，脱落尾蚴的数量增加表明该物种对法国寄生虫分离株的快速适应。
