Cyclospora (Cyclospora cayetanensis) is a parasite that is too small to be seen with the naked eye. A person can get infected by putting something in his/her mouth that was contaminated with feces (poop). Avoiding water and food that may be contaminated with feces is one of the best ways to prevent infection. Infected persons should wash their hands often to prevent the spread of infection. Persons who have previously been infected with Cyclospora can become infected again.