Cyclospora cayetanensis is a protozoan parasite that causes the diarrheal illness known as cyclosporiasis. People acquire this infection by consuming food or water contaminated with feces containing Cyclospora. Cyclosporiasis was not previously a reportable disease in the U.S., so its rise in prevalence is due in large part to the increased availability of tests that can detect Cyclospora. It is now a nationally notifiable disease, so physicians are required to report cases of this infection.
The first three cases of cyclosporiasis were reported in 1977 and 1978, but the parasite that was causing the illnesses could not at that time be identified as Cyclospora cayetanensis; it was not until 1979 that the correct identification was made.