Description and ultrastructure of lankesterella species infecting frogs in Kenya

Abstract

Two species of Lankesterella are described from Kenyan frogs. In the first, Lankesterella ptychadeni n. sp. from the frog Ptychadena mascareniensis (Dumeril & Bibron) found in the Lake Victoria region of Kenya, oogony and sporogony take place in the gut epithelium and in the lamina propria. Oocysts yield eight sporozoites which accumulate in both the gut mucosal epithelium and in the lamina propria. In the same frog merogony stages were traced in the liver, and sporogony stages, with eight sporozoite progeny, occurred in detached endothelial cells in the blood, alongside sporozoites in the erythrocytes. These stages represent either a different generation of the same species or belong to a different species. The second, Lankesterella dicroglossi n. sp. recovered from Dicroglossus occipitalis (Gunther), in a spring south of Lake Baringo in Kenya, walled oocysts are formed in the reticulo-endothelial cells of the liver, spleen, and lungs and in the blood-vessel endothelium. Infected endothelium detaches into the blood stream. Oocysts yield over 40 sporocysts. The latter were seen accumulating in macrophage centers, as were invading circulating erythrocytes. An ultrastructural study of L. ptychadeni oocysts and sporozoites reveales features in common with previously ultrastructurally studied Lankesterella spp., together with unique fine-structural features in the oocysts not reported to date: a large, rolled mitochondrion, an electron-dense tubulo-vesicular network, expanded Golgi-adjunct structures and endoplasmic reticulum filled with coarse granules.