Staff Advisory: Cyclosporiasis – What You Need to Know
July 13, 2026
Your patients and family members may ask you for advice regarding the increased incidence of cyclosporiasis. The following is a summary of the current epidemiology, diagnostics, and treatment options. For further detail, see Mathison and Pritt, 2021 (https://doi.org/10.3390/microorganisms9091863) and the CDC cyclosporiasis page (www.cdc.gov/cyclosporiasis/php/surveillance/index.html).
Background
Cyclosporiasis is an intestinal illness caused by the parasite Cyclospora cayetanensis, transmitted through ingestion of contaminated fresh produce or water. Humans are the only known host, and the organism cannot spread directly person-to-person since oocysts need 1–2 weeks outside the host to become infectious.
Increasing Public Health Concern
Reported U.S. cases have risen sharply over the past decade, spiking in 2019 and again in 2022–2023, when national totals stabilized around 3,000. Federal tracking became fragmented in 2025 after the CDC made Cyclospora reporting optional for state health departments. As of early July 2026, the CDC reports 843 confirmed domestic cases with roughly 1,500 more pending analysis, while state-level data (Michigan alone at 1,562 cases by mid-July) suggest the true national estimate is well above 2,900. Most cases are now domestically acquired (only ~21% report recent travel) and tied to imported fresh produce — especially leafy greens, herbs like cilantro and basil, and berries — during the May–August peak season.
Clinical Presentation
Incubation is about 7 days. Symptoms include watery diarrhea, appetite and weight loss, cramping, bloating, nausea, fatigue, and low-grade fever, and illness can be prolonged or relapsing if untreated. Immunocompromised patients (HIV/AIDS, transplant recipients) may have more severe, protracted illness.
Diagnosis
Cyclospora testing isn’t part of routine ova and parasite exams — it must be explicitly requested. Within the Baptist system, it’s included in the GI panel by PCR, so order “GI panel by PCR.” Cyclosporiasis is nationally notifiable; positive tests are automatically reported to the State of Florida, satisfying our reporting requirement.
Treatment
- Immunocompetent adults: TMP-SMX, one double-strength tablet twice daily for 7 days
- Immunocompromised adults: one DS tablet four times daily for 10 days, then secondary prophylaxis (one DS tablet three times weekly)
- Pediatric patients (2 months–18 years): 8–10 mg/kg TMP and 40–50 mg/kg SMX per day, divided into 2 doses, for 7–10 days (oral suspension available)
- Contraindications: infants under 2 months, sulfonamide hypersensitivity, folate-deficiency megaloblastic anemia, severe hepatic/renal impairment; TMP is absolutely contraindicated with dofetilide (Tikosyn); check for other drug interactions before prescribing
- Sulfa-intolerant adults: ciprofloxacin 500 mg twice daily for 7 days (less effective; no established alternative for sulfa-intolerant children)
Food Preparation Advice for Patients
Cyclospora oocysts resist standard chlorine-based washing, so rinsing under running water reduces but doesn’t eliminate risk. During peak season (May–August), advise patients to:
- Wash all fresh produce thoroughly under running water
- Cook vegetables when possible — heating to ≥70°C (158°F) kills the oocysts
- Briefly blanch produce meant to be eaten raw or lightly cooked (30–60 seconds in boiling water)
- Be especially cautious with cilantro, basil, mixed salad greens, mesclun, iceberg lettuce, snap peas, and raspberries
Immunocompromised patients (CD4 <200, transplant recipients, those on immunosuppressive therapy or chemotherapy) should avoid raw produce entirely during peak season, favor cooked options, blanch anything eaten raw, and peel fruits like bananas, oranges, and melons.
Thank you for your attention to this evolving public health issue.
Allan Feingold, MD, FRCP(C), FCCP — Medical Director, Occupational and Environmental Medicine, South Miami Hospital
Yvonne Johnson, MD — Chief Medical Officer, South Miami Hospital
Download the full advisory (PDF)
