Isospora papionis n. sp. (Eimeriidae) of the Chacma Baboon Papio ursinus (Kerr, 1792)

SYNOPSIS. Isospora papionis n. sp. is described from the chacma baboon Papio ursinis (Kerr, 1792). Histopathologic examination revealed 3 of 20 baboons to be infected, but no organisms were found on examination of the feces. Macrogametes and sporulated oocysts were observed in the small intestine, mainly in the jejunum and ileum, invariably in an epithelial or subepithelial location at the proximal portions of the crypts of Lieberkuhn. Intact sporulated oocysts averaged 17 by 11 μ and had very thin walls which were often partially collapsed between the sporocysts. The sporocysts were somewhat flattened on one side and averaged 11 by 8.5 μ. A large sporocyst residuum was present.