ABSTRACT
Coccidia have long been recognized as one of the most important groups of parasites that infect animals, especially domestic livestock. Coccidia were not discovered until the invention of the microscope by Leeuwenhoek, who probably saw coccidian life-cycle stages in the liver of a rabbit. Different genera of intestinal coccidia were initially distinguished based on the number of sporocysts within the oocyst and the number of sporozoites within each sporocyst. Sporocysts of Cystoisospora do not contain Stieda bodies, and the excystation process is similar except the proteolytic enzymes act on sutures in plates in the sporocyst wall, and the sporocyst wall collapses along these plates to liberate sporozoites. The sporocyst wall is smooth and has a Stieda body at the narrower end. The Stieda body consists of an upper homogenous portion and a lower portion that is more electron dense than the upper portion.
