Sarcocystosis is an infectious disease caused by species of Sarcocystis, an intracellular protozoan parasite. Sarcocystis was first reported in 1843. Humans can serve as definitive hosts, with intestinal sarcocystosis for two species acquired from eating undercooked meat: Sarcocystis hominis, from beef, and Sarcocystis suihominis, from pork. Humans may also serve intermediate hosts for non-human Sarcocystis spp. after the accidental ingestion of oocysts. This ingestion leads to muscular sarcocystosis.
Sarcocystis requires two hosts to maintain its life cycle: an intermediate host, in which cysts (sarcocysts) containing infectious zoites infect the muscles, and a definitive host that ingests the cysts, becomes infected with intestinal-stage parasites, and excretes oocysts or sporocysts into the environment.
