A case of cold agglutinin disease in a bottlenose dolphin (Tursiops truncatus).

Cold agglutinin disease, one of the serological classifications of immune-mediated hemolytic anemia, is caused by the production of autoantibodies that react with erythrocytes at low temperatures. A captive bottlenose dolphin presented with regenerative and hemolytic anemia. Anticoagulated whole blood was agglutinated at room temperature (approximately 18°C), with reversal of agglutination on warming to 37°C, indicating the presence of cold agglutinin. Based on these findings, this animal was diagnosed with cold agglutinin disease. Clindamycin, doxycycline, and prednisolone were administered orally to treat the infection and immune-mediated hemolytic anemia. Anemia gradually improved after initiation of pharmacotherapy, and erythrogenesis slowed as erythroblasts disappeared and reticulocyte count decreased in peripheral blood. This represents the first report of cold agglutinin disease in a cetacean.