- Protozoan infection that can cause gastrointestinal or muscle disease
Background
Microbiology
Epidemiology
- Zoonosis of primarily of cattle (S. hominis) and pork (S. suihominis), with a two-host cycle
- Worldwide, but most cases are in tropics or subtropics of Southeast Asia (especially Malaysia)
Life Cycle
- Tissue sarcocyst is eaten by the definitive host
- Sarcocyst releases motile bradyzoites which penetrate into the lamina propria
- Bradyzoites mature into male and female forms, followed by sexual reproduction creating oocysts
- Mature oocysts (containing two sporocysts) are shed
- Sporocysts are eaten by the other host
- Sporocysts release sporozoites, which penetrate the intestinal all and enter the vascular endothelium
- Asexual reproduction creates merozoites, which spread hematogenously to muscle
- In muscle, the merozoites develops into a sarcocyst, which contains two bradyzoites
- It takes about two months to become infections
Clinical Manifestations
Human intestinal sarcocystosis
- Mostly asymptomatic
- If symptomatic, may cause nausea, abdominal discomfort, diarrhea, and fever
- Incubation period, if diarrhea is a symptom, of 2 days
- Self-limited illness
Human muscular sarcocystosis
- Mostly asymptomatic, but can develop a fulminant eosinophilic myositis
- May develop fever, myalgias, eosinophilia, and elevated CK
Diagnosis
- Stool microscopy for intestinal disease
- Muscle biopsy for muscle disease
Management
- Supportive
- No known effective antiparasitic, although albendazole has been tried at least once
