Technical Abstract: Coccidia are obligate intracellular parasites normally found in the intestinal tract. They belong to phylum Apicomplexa, class Sporozoasida, order Eucoccidiorida, and, depending on the species, family Eimeriidae, Cryptosporidiidae, or Sarcocystidae. Coccidian genera that infect cats and dogs are Isospora (also called Cystoisospora), Hammondia, Besnoitia, Sarcocystis, Toxoplasma, Neospora (see Chapter 80), Cryptosporidium, and Cyclospora (see Chapter 82).2 A Caryospora infection is also discussed in this section. Another coccidian genus, Eimeria, found commonly in herbivores, birds, lagomorphs, and rodents, is found only in feces of dogs and cats after they ingest intestinal contents or feces from these animals. The oocysts pass unchanged through the feline or canine intestine. Some coccidians of dogs remain unclassified