Cyclospora cayetanensis is a parasite that causes diarrheal disease in humans, and perhaps in other primates.
Typical symptoms of Cyclospora cayetanensis infection include most commonly watery diarrhea, that can sometimes be described as explosive, along with abdominal cramping, loss of appetite, weight loss, nausea and vomiting, all associated with an early onset. It can also include headaches, and a low fever, sometimes described as flu-like symptoms, however it is possible that the infected host do not even have symptoms. These symptoms, if not treated can last an average of 7 days, but can range anywhere from a few days to a month or longer, and even though the infection can resolve itself, if treated with specific drugs, the symptoms are resolved faster, compared to untreated patients. It is always possible for symptoms of infection to relapse, or come back. Infection in travelers are more severe in symptoms, while in Cyclospora endemic countries about 70% of children often have asymptomatic infections, while adults are occasionally infected.
Cyclospora cayetanensis infection is not considered a fatal disease, and there have been no reported deaths attributed to the actual parasite in the United States, however it is when the infection induces protracted diarrhea onto the host, which could possibly lead to severe dehydration if not taken care.