A total of 4,298 snails Bradybaena similaris were collected from the rural area of Rio de Janeiro County and from the Counties of Paracambi and Itaguai, State of Rio de Janeiro. Two theousand and five of these snails had metacercariae in their pericardial cavity. The cllecting was done between October 1983 and September 1986. The anhual average prevalences were: 42.89% (1st year), 43.42% (2nd year) and 55.86% (3rd year). Experimental infection in chicks allowed the identification of these metacercariae as Postharmostomum gallium. The small variation in size observed among metacercariae from the same host indicates that recruitment does not occur on a continuous basis. Statistical analysis showed no correlation between the snail size and the number of metacercariae in the pericardical cavity, and that the snail mortality observed in the laboratry was due to the parasitic infection.
Natural parasitism; Bradybaena similaris; snail mortality; Postharmossomum gallium