noun, plural: trophozoites
Apicomplexa is a phylum comprised of protozoans characterized by having a special organelle called an apical complex, and most of them are single-celled, parasitic, and spore-forming. They are intracellular parasites. Their life cycle is comprised of stages where each has a particular cellular variety. Nevertheless, not all members have all the various life stages. An example of an apicomplexan with the trophozoite cell type is the Plasmodium species, the causative agent of malaria. Plasmodium species use two hosts (human and Anopheles mosquito) to complete its complex life cycle. In the human host, the sporozoites injected by the mosquito during a blood meal are circulated by the bloodstream. When they reach the liver cells of the human host they transform into trophozoites. The trophozoite is the active, amoeboid cell form of the Plasmodium. It loses its apical complex and surface coat. The tropozoites particularly invade the vacuole of the hepatocyte where they will go through schizogonic development. Their nucleus will undergo multiple divisions while their cell size increases. They develop and differentiate into merozoites.