[Description and characteristics of an amebocytic reaction in Lymnaea truncatula Müller infested by Fasciola hepatica L. (author's transl)].

The development of an amebocytic reaction is described in tissues of Lymnaea truncatula infested by Fasciola hepatica. When the snails are bred at 20 degrees C (uniform temperature), this reaction is maximum after five to seven weeks of infestation; afterwards the intensity of the reaction decreases until 10 weeks of infestation. This reaction also develops in snails bred at different temperatures (uniform temperatures of 25 degrees C or 16 degrees C, daily fluctuations from 4 degrees C to 18 degrees C). The maximum intensity of this reaction is chronologically delayed as the temperature goes down. The young snails infested after hatching do not show amebocytic reaction. When the infested snails fast for seven days the number of amebocytes rapidly decreases; these cells disappear from tissues from a snail fasting 14-35 days (depending on the snail organ). The significance of this amebocytic reaction is discussed.