Sarcocystis canis n. sp. (Apicomplexa: Sarcocystidae), the etiologic agent of generalized coccidiosis in dogs.

Sarcocystis canis n. sp. is proposed for the protozoon associated with encephalitis, hepatitis, and generalized coccidiosis in dogs. Only asexual stages are known in macrophages, neurons, dermal, and other cells of the body. The parasite is located free in the host cell cytoplasm without a parasitophorous vacuole; schizonts divide by endopolygeny. Schizonts are 5-25 x 4-20 microns and contain 6-40 merozoites. Merozoites are approximately 5-7 microns x 1 micron and do not contain rhoptries. The parasite is PAS-negative and reacts with Sarcocystis cruzi antiserum but not with Toxoplasma gondii, Neospora caninum, or Caryospora bigenetica antisera in an immunohistochemical test.