20 Jul What Is Cyclospora cayetanensis? An Infectious Disease Expert Explains Transmission, Seasonality, and Treatment
MedicalResearch.com Interview with:
Amesh A. Adalja, MD, FACP, FACEP, FIDSA
Spokesperson, Infectious Diseases Society of America
Senior Scholar, Johns Hopkins Center for Health Security
Dr. Adalja
MedicalResearch.com: What type of organism is Cyclospora cayetanensis?
Dr. Adalja: It is a protozoan parasite.
MedicalResearch.com: Where is it found? What are the symptoms of infection?
Dr. Adalja: Cases occur worldwide, but it is endemic in the tropics and subtropics.
MedicalResearch.com: How is it spread? Why does it occur periodically? Is there more spread during warm weather?
Dr. Adalja: It is spread when a human ingests an infective oocyst of Cyclospora. Its seasonal nature varies from place to place, and in countries like the United States and Canada, the risk is primarily related to importation of contaminated food products. Certain soil conditions are more conducive to the oocysts than others.
CDC image demonstrating three stained Cyclospora cayetanensis oocysts
MedicalResearch.com: Does chlorinated water help prevent transmission? Can it spread person-to-person?
Dr. Adalja: It is not deactivated by chlorine, but swimming pools are not a real mechanism of transmission as oocysts are not infective until a period of time has passed in conducive soil. It is not a true person-to-person transmitted pathogen.
MedicalResearch.com: What treatments are available?
Dr. Adalja: Antibiotics such as trimethoprim-sulfamethoxazole are the mainstay of treatment.
Reference: Cyclospora Outbreak Linked to Iceberg Lettuce in 5 States July 18, 2026.
Disclaimer: The information on MedicalResearch.com is provided for educational purposes only, and is in no way intended to diagnose, cure, or treat any medical or other condition. Some links are sponsored. Products, services and providers are not warranted or endorsed by MedicalResearch.com or Eminent Domains Inc. Always seek the advice of your physician or other qualified health provider and ask your doctor any questions you may have regarding a medical condition. In addition to all other limitations and disclaimers in this agreement, service provider and its third party providers disclaim any liability or loss in connection with the content provided on this website.
Last Updated on July 20, 2026 by Marie Benz MD FAAD