The pathology of cytauxzoonosis in a tsessebe (Damaliscus lunatus).

A natural, fatal case of cytauxzoonosis in a tsessebe is reported. The macroscopic and histologic pathology are described, the most significant lesion of which was severe, focal disseminate necrosis and haemorrhage in the liver. Similar but less severe lesions were present in the heart, skeletal muscles, kidneys and spleen in conjunction with a moderate interstitial pneumonia. Schizonts were found within mononuclear phagocytes and multi-nucleated syncytial cells in the liver, lungs, spleen and kidneys. Parasitised erythrocytes with up to 4 piroplasms per cell were seen. The ultrastructural features of the parasite are consistent with those of Cytauxzoon spp.