Ultrastructure studies on post-oocyst development of the lizard hemogregarine Hemolivia mariae in the tick Amblyomma limbatum

Abstract

The ultrastructural features of the development of Hemolivia mariae, a blood parasite of the Australian lizard, Tiliqua rugosa, from sporokinetes to sporozoites in their vector tick Amblyomma limbatum are described. Sporokinetes, released from oocysts, re-establish themselves in tick-gut epithelial cells within a parasitophorous vacuole, the wall of which becomes evaginating and anastomosing and is underlined extensively by endoplasmic reticulum. The sporozoites forming within the encysting sporokinete body become bordered by a prominent thick wall, which eventually forms the resistant sporocyst wall. The main differences between the ultrastructural features of Hemolivia and those of other hemogregarine taxa are discussed.