Histological studies on the effects of Apatemon cobitidis in its second intermediate host, the bullhead (Cottus gobio).

Pathological effects of Apatemon cobitidis (Trematoda) in its second intermediate host, the bullhead (Cuttus gobio) are described. Macroscopically pathology in bullheads is characterized by migrating and encysted metacercariae in body cavity, eyes, retrobulbous space, brain and rarely in muscles and subcutis. Histologically lymphohistiocytic reactions and hemorrhages could be observed. Migration of metacercariae in eyes and invasion of brain causes blindness and inability to adapt to the background. Other main life functions remain intact.