The Hawaiʻi Department of Health (DOH) has confirmed a case of cyclosporiasis in a member of the military based in Hawaiʻi.

The individual traveled internationally before returning to Hawaiʻi prior to getting sick. Based on their travel history, symptom onset and the known incubation period it is not known at this time if the infection was acquired in Hawaiʻi or while traveling. However, at this point in the DOH investigation, there is no evidence that this case changes the risk of cyclosporiasis in Hawaiʻi. The assessment of risk of cyclosporiasis to the public in Hawaiʻi remains low.

This case brings the total number of confirmed cyclosporiasis cases reported in Hawaiʻi in 2026 to four. The first case involved a non-resident visitor whose infection also was acquired outside of Hawaiʻi. The next two cases involved two Hawaiʻi residents who traveled internationally.

Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis. Eggs of the parasite shed in the feces of infected persons must mature outside the host, in the environment, before they become infectious to another person. People become infected by consuming food or water contaminated with the parasite. In the United States, outbreaks have most often been linked to certain fresh produce items. 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 may include loss of appetite, weight loss, stomach cramps or bloating, nausea, increased gas, fatigue and, less commonly, vomiting or low-grade fever. Without treatment, symptoms may last for several weeks or longer and can come and go.

The DOH will continue to monitor for additional cases and work closely with healthcare providers and public health partners to protect the health of Hawaiʻi residents and visitors.