Life Cycle and Transmission of Cyclospora cayetanensis : Knowns and Unknowns

Although infections with are prevalent worldwide, many aspects of this parasite's life cycle and transmission remain unknown. Humans are the only known hosts of this parasite. Existing information on its endogenous development has been derived from histological examination of only a few biopsy specimens. Its asexual and sexual stages occur in biliary-intestinal epithelium. In histological sections, its stages are less than 10 μm, making definitive identification difficult. Asexual (schizonts) and sexual (gamonts) are located in epithelial cells. Male microgamonts have two flagella; female macrogametes contain wall-forming bodies. Oocysts are excreted in feces unsporulated. Sporulation occurs in the environment, but there are many unanswered questions concerning dissemination and survival of oocysts. Biologically and phylogenetically, closely resembles spp. that parastize chickens; among them, most closely resembles in size. Here, we review known and unknown aspects of its life cycle and transmission and discuss the appropriateness of surrogates best capable of hastening progress in understanding its biology and developing mitigating strategies.