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Cyclosporiasis (Cyclospora cayetanensis)
1998 Case Definition

Clinical Description

An illness of variable severity caused by the protozoan Cyclospora cayetanensis and commonly characterized by watery diarrhea, loss of appetite, weight loss, abdominal bloating and cramping, increased flatus, nausea, fatigue, and low-grade fever. Vomiting also may be noted. Relapses and asymptomatic infections can occur.

Laboratory Criteria for Diagnosis

Laboratory-confirmed cyclosporiasis shall be defined as the detection—in symptomatic or asymptomatic persons—of Cyclospora

  • Oocysts in stool by microscopic examination, OR
  • In intestinal fluid or small bowel biopsy specimens, OR
  • Demonstration of sporulation, OR
  • DNA (by polymerase chain reaction) in stool, duodenal/jejunal aspirates or small bowel biopsy specimens.

Case Classification


Confirmed, symptomatic: a laboratory-confirmed case associated with one of the symptoms described above
Confirmed, asymptomatic: a laboratory-confirmed case associated with none of the above symptoms