Location: Animal Parasitic Diseases LaboratoryTitle: Fatal Sarcocystis canis-like hepatitis in an Indo-Pacific bottlenose dolphin (Tursiops aduncus) in Hong Kong Author
|Van De Bildt, M.w.g.|
|De Jong, A.w.|
Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2017
Publication Date: 2/15/2017
Citation: Calero-Bernal, R., Maur00, N., Hui, S., Kuiken, T., Van De Bildt, M., De Jong, A., Osterhaus, L., Sim, L., Gendron-Fitzpatrick, A., Carmena, D., Cerqueira-Cezar, C., Rosenthal, B.M., Dubey, J.P. 2017. Fatal Sarcocystis canis-like hepatitis in an Indo-Pacific bottlenose dolphin (Tursiops aduncus) in Hong Kong. Veterinary Parasitology. 235:64-68. Interpretive Summary: When disease strikes wildlife animals, the preliminary diagnosis may prove incorrect and it is important to understand the true nature of disease. Here, dolphins initially suspected of suffering from viral hepatitis were instead found to harbor parasites that were reminiscent of those previously seen in dogs and bears. Because of the novelty of this finding, the case merited a thorough characterization. Here, an international team reports the pathology of the disease and was able to obtain, characterize, and compare DNA extracted from the parasite responsible for the illness. Sarcocystis canis, or a parsite very closely related to this species, was deemed responsible. The expanding range of known hosts for such parasites merits further attention, and will interest veterinarians, conservation biologists, and epidemiologists.
Technical Abstract: Unlike most species in the genus Sarcocystis, Sarcocystis canis has a broad intermediate host range. Its life cycle is incompletely known and most reports are from the USA. Here we report fatal hepatitis in a 4 year old male Indo-Pacific bottlenose dolphin (Tursiops aduncus) from Hong Kong associated with a S. canis-like infection. Diagnosis was made based on clinical presentation, histopathology, transmission electron microscopy (TEM), and molecular characterization. Microscopically, S. canis infection was confined to the liver. Immature and mature schizonts were found in hepatocytes and the parasite was associated with generalized hepatic necrosis. By TEM, schizonts divided by endopolygeny, and merozoites lacked rhoptries. Molecular characterization of parasites present in liver and brain tissues at the cox1 gene showed a high degree of identity (97-98%) and clustered together with Sarcocystis canis, S. lutrae, S. arctica, S. speeri, S. turdusi, and S. rileyi in a phylogenetic study. This is the first report of S. canis-like infection from Asia.