Health Department confirms 4th case of cyclosporiasis in Hawaii

The state Department of Health confirmed a fourth case of cyclosporiasis in the islands today, identifying the patient as a military service member based in Hawaii.

The individual traveled internationally before returning to Hawaii prior to falling ill. Based on travel history, symptom onset and the known incubation period, health officials said it is not yet clear whether the infection was acquired locally or during travel. DOH investigators emphasized that there is no evidence changing the overall risk level in Hawaii, which remains low for the general public.

This latest diagnosis brings the total number of confirmed cyclosporiasis cases reported in Hawaii in 2026 to four. The first case involved a non-resident visitor who acquired the infection outside the state, while the second and third cases involved Hawaii residents who had traveled internationally.

Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis. Eggs of the parasite shed in feces must mature in the environment before becoming infectious to others. People become infected by consuming contaminated food or water, and outbreaks in the U.S. have most frequently been linked to imported fresh produce. The illness is not typically spread directly from person to person.

Symptoms usually begin about one week after exposure but can appear anywhere from two days to two weeks later. The most common symptom is frequent, watery diarrhea. Other symptoms include loss of appetite, weight loss, stomach cramps, bloating, nausea, increased gas, fatigue and, less commonly, vomiting or low-grade fever. Without treatment, symptoms may last for several weeks and can recur over time.

DOH officials routinely investigate reportable diseases to identify potential infection sources and monitor for signs of local transmission. The illness is treatable with prescription antibiotics, and individuals experiencing persistent diarrhea are encouraged to contact a healthcare provider.

Health officials advise the public to reduce risk by washing hands thoroughly with soap and water, washing fresh fruits and vegetables under running water before preparation and seeking medical care if severe diarrhea develops after travel.