The populations of Galba truncatula, known for their natural infections with Haplometra cylindracea (Digenea, Plagiorchioidea), are better intermediate hosts for metacercarial production of Fasciola hepatica
Laboratory investigations on Galba truncatula were carried out to determine if snails coming from four populations known to be natural intermediate hosts of Haplometra cylindracea, a digenean species of frogs, would not be better hosts for experimental infections with Fasciola hepatica than those originating from two communities in which H. cylindracea was never found in the past years. Uninfected G. truncatula were used to constitute six groups of snails (one per population) before being subjected to individual monomiracidial exposures with F. hepatica. Insignificant differences between mean values were noted for snail survival at day 30 post-exposure, prevalence of snail infection with F. hepatica, and prepatent period. In contrast, the duration of cercarial shedding and the number of F. hepatica cercariae in the four groups known for natural infections with H. cylindracea were significantly greater. The use of these last lymnaeid populations for experimental infections with F. hepatica allows to have high numbers of cercariae because of long patent periods and, as a consequence, strongly reduces the cost price of these larvae for scientific purposes and/or commercial production.