Cardiac Truncus Arteriosus in an Eastern Black Rhinoceros (Diceros bicornis michaeli).

This case report describes congenital truncus arteriosus in a 1-month-old Eastern black rhinoceros (Diceros bicornis michaeli). From the first day of life the animal was underweight and from the 22nd day of life displayed respiratory signs that exacerbated with time leading eventually to collapse and death. Post-mortem examination revealed a single truncus arteriosus originating from the right ventricle leading to two separated pulmonary arteries and the aorta, with the ventricular septum showing a focal communicating defect. Based on the gross examination and current human classifications, the truncus arteriosus was classified as type III or A2. This is the first description of persistent truncus arteriosus in an Eastern black rhinoceros.