Capybaras are the world‘s largest rodents and, like other rodents, this species is prone to dental disease (teeth overgrowth, malocclusion and odontomas),2 but few cases of heart disease had been reported1. A case of congenital heart disease was diagnosed in a 1-year-old castrated male capybara (Hydrochaeris hydrochaeris), which was evaluated for lethargy, weight loss, and bilateral epistaxis. Blood sample results indicated a severe erythrocytosis and metabolic derangements including azotemia, hypercalcemia, hyperkalemia, and lactic acidemia. The animal received supportive medical care and therapeutic phlebotomy was performed under anesthesia. Despite treatment, the animal declined and was euthanized. A post-mortem computed tomography (CT) scan did not expose any major abnormality. Gross necropsy revealed multiple noteworthy cardiac abnormalities including vessels in atypical positions, abnormal ventricular septation, and endocardiosis, which likely precipitated the secondary erythrocytosis. Histopathology findings included myocardial fibrosis, liver fibrosis, marked lung congestion and hemorrhage as well as biliary hyperplasia, which confirmed the diagnosis of a congenital heart disease. To the knowledge of the authors, this is the first description of this kind of congenital heart reshuffle in a capybara.
The authors would like to thank the animal care and veterinary staff at the Houston Zoo, Dr. Maureen O‘Brien, Dr. Carley Giovanella, and the staff at Gulf Coast Veterinary Specialists hospital.
1. Juan-Sallés C, Martínez LS, Rosas-Rosas AG, et al. Pulmonary arterial disease associated with right-sided cardiac hypertrophy and congestive heart failure in zoo mammals housed at 2,100 m above sea level, J Zoo Wildl Med. 2015;46(4):825–832.
2. Yarto-Jaramillo E. Rodentia (capybara). In: Fowler ME, Miller, eds. Zoo and Animal Medicine, 8th ed. Elsevier; 2015;384–421.