Trypanosomiasis (surra) in the captive Sumatran rhinoceros (Dicerorhinus sumatrensis sumatrensis) in Peninsular Malaysia.

Abstract

Five captive Sumatran rhinoceros (Dicerorhinus sumatrensis sumatrensis) housed in a facility in Selangor Malaysia died in a biphasic epidemic that spanned 18 days. Four of the five rhinos had been wild-caught in peninsular Malaysia and translocated into captivity; one was the only offspring of a female that had been pregnant at the time of capture. Clinical signs included initial depression and anorexia followed by rapidly progressing incoordination, muscle tremors, nasal hemorrhage, recumbency and labored breathing, followed by death. Despite broad-spectrum antibiotic and supportive therapy, all five rhinos succumbed. Trypanosomes identified as Trypanosoma evansi were detected in blood smears taken just prior to death from the last two animals. Gross pathology was nonspecific; however, histopathologic examination revealed multi-systemic disease compatible with historical reports of surra in other animals. Three animals had intralesional trypanosomes and extravascular hemolysis; three of four animals for which spleen was available had unique and characteristic splenic lesions consisting of marked enlargement of periarteriolar sheaths with lymphoid depletion. Trypanosomes were identified in the brain of one animal in association with endothelial hypertrophy. Immunohistochemistry was performed on tissue samples to further characterize the disease. A herd of buffalo located adjacent to the Sumatran Rhino Conservation Center shared a common fence with the 10-acre reserve where the first animal had been housed for the two weeks immediately prior to its death. This outbreak represents the first report of surra in the Sumatran rhinoceros.