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. [from
ORDO]