Hepatocystosis in a baboon (Papio anubis)

A 26-lb wild-caught adult female baboon was obtained from a commercial vend or. Routine tests for parasites, pathogenic bacteria, and tuberculosis were negative throughout the ill-week quarantine. However, routine radiographs performed at the end of the quarantine period detected multiple small radio opaque nodules evenly dispersed throughout the liver. A hepatic biopsy was obtained during routine ovariectomy of the baboon, and a diagnosis of granu lomatous hepatitis made. Approximately 1 year after her arrival, the baboon was euthanized for reasons unrelated to the hepatitis. The liver contained multiple (40 to 50) white foci that were 1 to 3 mm in diameter; these foci were visible on the surface as well as throughout the parenchyma, There wa s multifocal, moderate capsular fibrosis, with adhesions between the hepati c lobes and between the diaphragm and liver. Histologic examination reveale d multiple degenerate Hepartocystis sp. merocysts. H. kochi and H. simiae a re malarial-type nonpathogenic protozoa endemic to Old World nonhuman prima tes, including baboons. Infected animals are asymptomatic and do not experi ence hemolysis. Transmission requires an insect vector, therefore infection with Hepatocystis sp, has minimal implications for colony health, There is no known danger of transmission to humans.