Source: Ohio Department of Health
Situation Summary
The Ohio Department of Health (ODH), local health departments, and state and federal public health partners are investigating an outbreak of cyclosporiasis in five states, including Ohio and several neighboring states, linked to shredded iceberg lettuce from Mexico.
As of July 16, there were 1,246 cases of cyclosporiasis that had been reported in Ohio this year. Historically, Ohio has reported fewer than 150 cases of cyclosporiasis per year. Similar increases have been reported in neighboring states. Cases are concentrated in northwest Ohio but have been reported throughout the state.
Physicians and other healthcare professionals should consider Cyclospora infection as a potential cause of prolonged or relapsing diarrheal illness and, if indicated, specifically request testing for Cyclospora when ordering testing.
Guidance for Physicians
Overview
Cyclosporiasis is an intestinal infection caused by the parasite Cyclospora cayetanensis. Infection occurs through ingestion of contaminated food or water, and symptoms typically begin about one week after exposure.
Cyclospora infection usually causes prolonged watery diarrhea, often accompanied by loss of appetite, abdominal cramping or bloating, nausea, or fatigue. Without treatment, illness may persist for weeks and can follow a remitting‑relapsing pattern.
While travel to tropical or subtropical regions can increase risk, the current multi-state outbreak has been linked to shredded iceberg lettuce from Mexico. Previous outbreaks in the U.S. have been linked to various types of fresh produce.
Diagnosis
Consider Cyclospora as a potential cause of prolonged or relapsing diarrheal illness, particularly with a history of recent international travel, consumption of fresh produce, or exposure to a known outbreak source of cyclosporiasis.
If clinically indicated, specifically order testing for Cyclospora. Standard ova and parasite (O&P) exams typically do not include Cyclospora, and not all gastrointestinal panels include a target for Cyclospora.
People infected with Cyclospora shed oocysts (rather than cysts or ova) in their feces, and low numbers of oocysts can make detection difficult. Multiple stool specimens collected on different days may improve diagnostic yield.
Testing
For patients with no history of international travel during the two-week incubation period (prior to symptom onset), please submit Cyclospora-positive bulk stool or stool specimens to the ODH Lab for genotyping. Specimens in any fixative or transport media, except formalin, may be accepted. Fecal swabs are not the preferred sample type. For additional information on specimen types, please see information on Cyclospora genotyping from the Centers for Disease Control and Prevention (CDC).
Utilize the eLIMS portal to request send-out testing for Cyclospora genotyping and include the community outbreak number, 2026-26-155, on submission paperwork to indicate the specimen is part of the current outbreak. Print the Requisition Form created in eLIMS and include it with the specimen when shipped. If you do not have an account with eLIMS or if you have questions about the submission process, please contact the ODH Laboratory by calling 888.634.5227 or sending an email to ODHLabs@odh.ohio.gov.
Treatment
Cyclosporiasis is often self‑limiting in immunocompetent patients, but illness can last weeks without treatment and may follow a remitting–relapsing course.
Trimethoprim‑sulfamethoxazole (TMP‑SMX) is the treatment of choice. For dosing and additional treatment considerations, please refer to the CDC’s Clinical Care guidance.
Per Ohio Administrative Code 3701-3-13, individuals with cyclosporiasis who attend childcare centers or who work in sensitive occupations are to be excluded until diarrhea has ceased and effective antimicrobial therapy has begun.
Reporting
Cyclosporiasis is a Class B reportable infectious disease in Ohio. Report a case, suspected case, and/or positive laboratory result to the local public health department in which the patient resides by the close of the next business day. If patient residence is unknown, report to the local public health department in which the reporting physician or other healthcare professional laboratory is located.
Contact Information
For general questions related to cyclosporiasis, physicians and other healthcare professionals and facilities should contact their local health department. Ohio local health departments should contact the ODH Bureau of Infectious Diseases at by calling 614.995.5599 or sending an email to ORBIT@odh.ohio.gov.
- American Academy of Family Physicians: What Family Physicians Need to Know
- ODH Infectious Disease Control Manual: Cyclosporiasis.
- CDC: Clinical Overview of Cyclosporiasis.
- S. Food & Drug Administration: Cyclospora.