Prevalence of Haplometra cylindracea infection in three species of Lymnaeasnails in central France

Field investigations were performed over a 2- or 3-year period at five site s in central France to determine the prevalence of Haplometra cylindracea i nfection in three species of adult Lymnaea, and to compare it with that of Fasciola hepatica infection recorded in the same snails. L. glabra, L. palu stris, and L. truncatula harboured Haplometra a larval forms but the preval ence of this infection varied according to the site and snail species studi ed. The prevalences in May ranged over 0-66.9% in L. glabra, 3-7.7% in L. p alustris, and 0-31.5% in L. truncatula. The mean intensity of H. cylindrace a infection in May did not show any significant variation, whatever the sit e and species studied. The prevalence of F. hepatica infection was signific antly lower in snails collected in sites known for H. cylindracea infection than in those originating from nearby meadows (0-1% instead of 1-5%). H. c ylindracea could develop in some Lymnaea species and its occurrence had an impact in snails by decreasing the prevalence of F. hepatica infection.