Single-species infections of Echinostoma caproni cercariae in pulmonate snails and concurrent infections of E. caproni and Echinostoma trivolvis cercariae in Biomphalaria glabrata

Abstract

Single-species infections of Echinostoma caproni cercariae in various pulmonate snails showed that a higher percentage of cercariae encysted successfully in Biomphalaria glabrata than in other snail species and that the percentage encystment was significantly greater in B. glabrata than in either Helisoma trivolvis or Lymnaea elodes. There were significant differences in cyst diameter, thickness of outer and inner cysts, and diameter of excretory concretions between E. caproni and Echinostoma trivolvis metacercariae. These morphological differences helped to distinguish each species of cyst in concurrent cercarial infections of E. caproni and E. trivolvis in B. glabrata. Moreover, in concurrent infections E. trivolvis localised only in the saccular kidney, whereas E. caproni occurred in both the saccular kidney and the pericardium.