A rare parasitic disease characterized by infection with sarcocystis species with humans as definitive (intestinal sarcocystosis) or aberrant intermediate (muscular sarcocystosis with development of sarcocysts in myocytes of skeletal, cardiac, and smooth muscle) host. Enteric infection is often mild or asymptomatic but may cause symptomatic enteritis with nausea, abdominal pain, diarrhea, and vomiting. Symptoms of muscular sarcocystosis include fever, fatigue, headache, cough, myalgia, and arthralgia, among others, with the possibility of a long-lasting, waxing and waning course.

Infection of the striated muscle of mammals by parasites of the genus SARCOCYSTIS. Disease symptoms such as vomiting, diarrhea, muscle weakness, and paralysis are produced by sarcocystin, a toxin produced by the organism.

Sarcosporidiosis is defined as infection with Sarcocystis, which is an intracellular protozoan parasite. Sarcocystis predominantly infects nonhuman animals but can also infect humans.