Cyclospora cayetanensis is an acid-fast, coccidian-like, parasitic protozoan with the size of 8-10 micrometer in diameter. Cyclospora cayetanesis was recently recognized as a new (intestinal) protozoan pathogen of human (1993, species name was proposed in 1994) and was identified as the cause of the prolonged diarrhea of travelers as well as immunocompetent and immunocompromised patients.