Figure 1.

Life cycle of Cyclospora cayetanensis. Caption: If a susceptible human ingests sporulated oocysts in contaminated food or water, the sporozoites inside the sporocysts excyst in the gut lumen and invade enterocytes of the epithelium of duodenum and jejunum where the sporozoites transform into trophozoites. Trophozoites subsequently form 2 types of schizonts (asexual multiplication). Type I schizonts contain 8–12 merozoites. Type II schizonts contain 4 merozoites. Then, type II merozoites form gamonts (sexual multiplication). There are two types of gamonts: microgamonts and macrogamonts. Microgamonts fertilize macrogamonts to form the zygote. Oocysts then are formed in enterocytes and are excreted unsporulated in the feces. The prepatent period is thought to be around one week. Unsporulated oocysts are not infectious—they need to sporulate to became infective for a host. Under laboratory conditions, at 22 °C and 30 °C, sporulation will take between 7 and 14 days to occur outside the host. A sporulated oocyst contains two sporocysts, each with two sporozoites.