Histopathologic report of infestation by Centrocestus formosanus in Iranian grass carp and common carp

Flukes cause severe and lethal diseases in various animals comprising fish. Both adult and larval stages are found in fish. Centrocestiasis is an infection of the fish gills by heterophyid trematode Centrocestus formosanus. In summer 2014, 35 fingerling grass carp and 30 common carp weight of 6 grams were referred to the veterinary hospital of Shahid Chamran University of Ahvaz. In the wet mount of the skin, mild infection of trichodina was observed. Wet mount of grass carp gills revealed large number of parasitic cysts between gill filaments. The cysts were quite clear and contained pear-shaped parasites. In histopathological examination, filaments of gill were thick and distorted. According to the wet mount and histopathologic results, metacercariae was chracterised to belong to heterophyidae, C. formosanus.