[Experimental studies on the generalized amoebocytic reaction in Lymnaea truncatula Müller infected by Fasciola hepatica L. (author's transl)].

Lymnaea truncatula collected in the field showed a generalized amoebocytic reaction if the snails were infected by Fasciola hepatica. This cellular reaction was also present in snails bred under controlled conditions (20 degrees C) with evolutive or abortive infection. The intensity of the cellular reaction was similar when each snail was exposed to a single miracidium and then has developed evolutive or abortive infection. The uninfected snails and the control snails only had a few amoebocytes. There were variations in the amoebocytic intensity according to the geographic strain of snails or of miracidia. The intensity of the reaction increased in snails with evolutive infection when the number of miracidia for one exposure or the number of exposures increased. For the same population, the intensity was always similar with abortive infection, whatever the numbers of miracidia and of exposures. The significance of these observations is discussed.