Coccidian protozoan. All coccidians are intracellular parasites of various vertebrates and invertebrates. Eimeria tenella infects chick intestinal epithelial cells and is of veterinary importance. The trophozoites invade host cells, proliferate as merozoites by schizogony which can then infect adjacent cells if released. Merozoites differentiate to male or female gamonts that fuse to form a zygote that undergoes division to form eight zoites that are retained within a zygocyst. If the zygocyst is ingested by a new host the zoites emerge, and reinfect the host as trophozoites.
Dictionary of molecular biology. 2004.