A comparison of aspects of the biology of two subspecies of Typhlocoelum cucumerinum (Digenea: Cyclocoelidae) in three families of snails (Physidae, Lymnaeidae and Planorbidae)

Abstract

Scott M. E., Rau M. E. and McLaughlin J. D. 1982. A comparison of aspects of the biology of two subspecies of Typhtocoelum cucumerinum (Digenea: Cyclocoelidae) in three families of snails (Physidae, Lymnaeidae and Planorbidae). International Journal for Parasitology 12: 123–133. Experimental investigations of Typhlocoelum cucumerinum sisowi and Typhlocoelum cucumerinum cucumerinum in three species of snails, Physa gyrina, Helisoma trivolvis and Lymnaea elodes not only revealed differences between the two subspecies but also revealed differences dependent on the species of intermediate host. Typhlocoelum cucumerinum sisowi miracidia have higher infectivities in P. gyrina and H. trivolvis than in L. elodes whereas T. c. cucumerinum miracidia are highly infective to P. gyrina and less so to L. elodes and H. trivolvis. The growth rate of rediae of the two subspecies varies depending on the snail, the rate being lowest for both parasites in L. elodes. Metacercarial production is higher for both subspecies in P. gyrina and H. trivolvis than in L. elodes and metacercariae of both subspecies have the highest infectivity to ducks when reared in P. gyrina. Although rediae and metacercariae are found in the pericardial cavity of all three species of snails, it is only in H. trivolvis that an intense cellular response was observed around degenerate metacercariae at 4 months post-infection. According to these data, P. gyrina appears to be the most suitable host for both subspecies.