Hawaii DOH Investigates First Locally Acquired Cyclosporiasis Case on Oʻahu

The Hawaii Department of Health is investigating a locally acquired case of cyclosporiasis involving an Oahu resident who fell ill at the end of July without any history of travel outside the state, according to an agency announcement on August 26, 2026. The infection marks the sixth reported case of cyclosporiasis in Hawaii since the beginning of July, though the previous five cases all involved individuals who had traveled outside the islands during their likely exposure periods.

State health officials are reviewing potential food and environmental exposures to determine how the infection occurred, though no suspected contaminated food source has been identified. According to the Hawaii Department of Health, a single locally acquired case does not change the overall risk assessment for the general public, which remains low.

Understanding Cyclosporiasis and Transmission

Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis, according to the Hawaii Department of Health. People become infected by consuming food or water contaminated with the parasite. Symptoms usually begin about one week after exposure, though the incubation period can range from two days to two weeks.

The most common symptom is frequent, watery diarrhea. Additional symptoms can include loss of appetite, weight loss, stomach cramps, bloating, nausea, increased gas, fatigue, and less commonly, vomiting or a low-grade fever. The parasite is not known to spread directly from person to person because it must mature outside the body in the environment before becoming infectious.

Broader Outbreaks and National Context

Public health agencies are also examining whether local infections connect to broader national events. According to federal and state health officials, a multistate outbreak of cyclosporiasis in the United States has been linked to iceberg lettuce processed by Taylor Farms de Mexico. Taylor Farms de Mexico initiated a recall of all iceberg lettuce sourced from central Mexico on July 17, 2026. As of August 20, 2026, that multistate outbreak includes 10,930 illnesses reported across 17 states.

State health officials stated that no recalled iceberg lettuce was identified as being distributed to or sold in Hawaii. The Hawaii Department of Health and the Centers for Disease Control and Prevention are working to determine whether any local cases could be related to this or other multistate outbreaks.

Prevention and Medical Guidance

Cyclosporiasis is treatable with prescription antibiotics, but without treatment, symptoms may last for several weeks or longer and can come and go. Individuals experiencing severe diarrhea or diarrhea lasting longer than a few days are advised by health officials to contact a healthcare provider. Healthcare providers who suspect cyclosporiasis are encouraged to report cases to the Hawaii Department of Health and submit appropriate specimens to commercial laboratories for specialized testing.

The Hawaii Department of Health recommends several steps to reduce the risk of infection:

• Wash hands with soap and water before preparing or eating food and after using the restroom.
• Wash fresh fruits and vegetables under running water before eating, cutting, or cooking them.
• Seek medical care for severe diarrhea or symptoms lasting longer than a few days.