The intestinal disease cyclosporiasis is caused by the protozoan Cyclospora cayetanensis. It is endemic to tropical and subtropical regions and therefore uncommon in the United States, although there have been outbreaks associated with contaminated produce imported from regions where the protozoan is more common.

protozoal disease, disease caused by protozoans. These organisms may remain in the human host for their entire life cycle, but many carry out part of their reproductive cycle in insects or other hosts. For example, mosquitoes are vectors of plasmodium, the cause of malaria. See also entamoeba; Giardia lamblia; sleeping sickness.

Overview More Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes. It is preventable and curable. There are 5 parasite species that cause malaria in humans, and 2 of these species – Plasmodium falciparum and Plasmodium vivax – pose the greatest threat.