The Centers for Disease Control and Prevention and others are investigating an increase in reported cases of cyclosporiasis – an intestinal illness caused by the parasite Cyclospora cayetanensis. People can become infected with Cyclospora by consuming food or water contaminated with the parasite; it is not transmitted directly from one person to another person. The CDC recommends health care providers consider a diagnosis of cyclosporiasis in patients who have prolonged or remitting-relapsing diarrheal illness. If indicated, health care providers should order appropriate testing. In addition, providers should report cases to their local health departments. For more information, see the CDC Health Advisory.