Cell invasion by Theileria sporozoites

Theileria are intracellular protozoan parasites of veterinary importance, and their impact on livestock production in many developing countries has a significant negative effect on the quality of human life. Host cell invasion is a crucial aspect of Theileria biology. The morphological events in Theileria sporozoite invasion of bovine lymphoid cells are well established and it is clear that the process differs significantly from host cell invasion in other apicomplexans, such as Plasmodium and Toxoplasma. This article highlights some of these differences, and compares sporozoite entry with the entry processes of other Theileria life cycle stages. Although details of these processes in the tick host remain vague, it is apparent that Theileria uses different invasion strategies in different hosts.