Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis.

People can become infected with Cyclospora by consuming food or water contaminated with the parasite. People traveling to countries where the disease is endemic may be at increased risk for infection.

Image: Cyclospora cayetanensis oocysts are excreted unsporulated (non-infective); they usually require at least 1 week under laboratory conditions to sporulate (become infective). An undifferentiated oocyst is shown next to a sporulating oocyst that contains two maturing sporocysts (A). An oocyst is mechanically ruptured and releases one of its two immature sporocysts (B). One free sporocyst is shown with two free sporozoites, the infective stage of the parasite (C). Credit: CDC/DPDM