At least 26 people in Nebraska and Iowa have fallen ill with infections of the parasite Cyclospora in recent days, according to Health officials are still investigating the source of the disease, which is contracted through contaminated food or water. Physicians have been advised to test people experiencing diarrhea for the parasite. Cyclospora outbreaks have commonly been linked to fresh produce in the past, especially berries. According to the U.S. Centers for Disease Control and Prevention, it is rarely infectious from person to person. The Nebraska cases have occurred primarily in the eastern part of the state, while the Iowa cases are largely from central and eastern Iowa. Other symptoms of Cyclospora infection include fatigue, nausea, abdominal cramping and fever.