DIPLOSTOMATID-METACERCARIAE IN THE BRAIN OF SILVERSIDES FROM LAKE-RINIHUE, CHILE

The tissue locations and effects produced by metacercariae of Diplosto mum (Austrodiplostomum) mordax and Tylodelphys destructor in the brain of 30 silversides (Basilichthys australis) from Lake Rinihue in Chile , were evaluated. Metacercariae were mainly observed in tile interlobu lar infoldings, meninges and ventricles of the brain. The prevalence w as 18 (60%) and the intensities were usually low (1 to 9 metacercariae ), with no inflammation or invasion of tile parenchyma, except for one fish which had 130 parasites associated with a moderate inflammatory reaction. Asymmetry in the distribution of metacercariae in the cerebr al hemispheres was observed in one (3%) of the 30 fish.