Larval productivity ofFasciola giganticain two lymnaeid snails

Abstract

AbstractTwo groups ofGalba truncatulaand two groups ofLymnaea natalensiswere experimentally infected withFasciola giganticato determine if snail species had an influence on the redial burden and cercarial shedding of this trematode when snails of both species were infected with the same isolate of miracidia. In the two groups used for the study of redial burden, the total number of free rediae was significantly higher at day 49 post-exposure inL. natalensisthan inG. truncatula. In the groups used for cercarial shedding, the life-span of cercaria-shedding snails and those of infected snails which died without cercarial emission, and the duration of the prepatent period were significantly longer inL. natalensisthan those noted inG. truncatula. However, the mean numbers of shed cercariae did not significantly differ and showed no differences in their daily distribution throughout the shedding period. These results demonstrate thatG. truncatulamight be the principal intermediate host ofF. giganticain Egypt, at least in the areas where this lymnaeid species lives.