EN
The study diagnosed the first case of sarcocystosis in a mallard duck and drake in Poland. Both birds were lean and their anatomopathologic examination indicated a large number of rod-shaped sarcocysts in the pectoral muscles and esophagus. The sarcocysts were similar in shape and size to a grain of rice. Fat degeneration, enlargement and rupture of parasitized muscle fibers were diagnosed following histopathology examination of muscle pieces.