You’ve seen the headlines: a food-borne parasite is infecting people across the US, leaving them chained to the toilet sometimes for weeks on end, as they are ravaged by wave after wave of gastrointestinal upset. What the heck is cyclosporiasis and where did it come from? How scared should we be of our raspberries or lettuce or cilantro? To dish out the answers as fast we could, we put together this fact-filled episode about the biology of Cyclospora cayetanensis, how this parasite makes you sick, when we first learned about it (more recently than you might think), and what we know about this current outbreak (or outbreaks). We also probe how recent changes to foodborne pathogen surveillance on a national scale are contributing to the challenges in understanding the scope and origin of outbreaks such as this. You don’t want to miss this one!
| History | Biology |
| Ashford, R. W. “Occurrence of an undescribed coccidian in man in Papua New Guinea.” Annals of Tropical Medicine & Parasitology 73.5 (1979): 497-500. | CDC Cyclosporiasis Surveillance. July 10th, 2026. https://www.cdc.gov/cyclosporiasis/php/surveillance/index.html |
| Brown, Gigi H., and John C. Rotschafer. “Cyclospora: review of an emerging parasite.” Pharmacotherapy: The Journal of Human Pharmacology and Drug Therapy 19.1 (1999): 70-75. | Michigan Infectious Diseases Outbreaks: https://www.michigan.gov/mdhhs/keep-mi-healthy/infectious-diseases/infectious-disease-outbreaks |
| Connor, B. A. “Cyclospora infection: a review.” ANNALS-ACADEMY OF MEDICINE SINGAPORE 26 (1997): 632-636. | Lucas County Health: https://lucascountyhealth.com/cyclo/ |
| Curry, A., and H. V. Smith. “Emerging pathogens: Isospora, Cyclospora and microsporidia.” Parasitology 117.7 (1999): 143-159. | CDC NNDSS weekly statistics: https://stacks.cdc.gov/cbrowse?parentId=cdc%3A49375&terms=&subject_topic%5B0%5D=Cyclosporiasis&start=0 |
| Hadjilouka, Agni, and Dimitris Tsaltas. “Cyclospora cayetanensis—Major outbreaks from ready to eat fresh fruits and vegetables.” Foods 9.11 (2020): 1703. | Giangaspero, A. and Gasser, R.B., 2019. Human cyclosporiasis. The Lancet Infectious Diseases, 19(7), pp.e226-e236. |
| Henao, Olga L., et al. “Foodborne diseases active surveillance network—2 decades of achievements, 1996–2015.” Emerging infectious diseases 21.9 (2015): 1529. | Mansfield, L.S. and Gajadhar, A.A., 2004. Cyclospora cayetanensis, a food-and waterborne coccidian parasite. Veterinary parasitology |
| Strausbaugh, Larry J., and Barbara L. Herwaldt. “Cyclospora cayetanensis: a review, focusing on the outbreaks of cyclosporiasis in the 1990s.” Clinical Infectious Diseases 31.4 (2000): 1040-1057. | Ortega, Y.R., Sterling, C.R., Gilman, R.H., Cama, V.A. and Diaz, F., 1993. Cyclospora species–a new protozoan pathogen of humans. New England Journal of Medicine, 328(18), pp.1308-1312. |
| Herwaldt, Barbara L., Marta-Louise Ackers, and Cyclospora Working Group. “An outbreak in 1996 of cyclosporiasis associated with imported raspberries.” New England Journal of Medicine 336.22 (1997): 1548-1556. | Soave, R., 1996. Cyclospora: an overview. Clinical Infectious Diseases, 23(3), pp.429-435. |
| Huang, Philip, et al. “The first reported outbreak of diarrheal illness associated with Cyclospora in the United States.” Annals of Internal Medicine 123.6 (1995): 409-414. | Hadjilouka, A. and Tsaltas, D., 2020. Cyclospora cayetanensis—Major outbreaks from ready to eat fresh fruits and vegetables. Foods, 9(11), p.1703. |
| Li, Junqiang, et al. “Cyclospora cayetanensis infection in humans: Biological characteristics, clinical features, epidemiology, detection method and treatment.” Parasitology 147.2 (2020): 160-170. | Barratt, J.L., Park, S., Nascimento, F.S., Hofstetter, J., Plucinski, M., Casillas, S., Bradbury, R.S., Arrowood, M.J., Qvarnstrom, Y. and Talundzic, E., 2019. Genotyping genetically heterogeneous Cyclospora cayetanensis infections to complement epidemiological case linkage. Parasitology, 146(10), pp.1275-1283. |
| Ortega, Ynes R., et al. “Cyclospora species–a new protozoan pathogen of humans.” New England Journal of Medicine 328.18 (1993): 1308-1312. | Morton, V., Janicki, R., Dumoulin, D., Dixon, B. and Guy, R., 2025. Epidemiology of Cyclospora cayetanensis infections in Canada: 2000–2022. Foodborne Pathogens and Disease. |
| Relman, David A. “Cyclospora: whence and where to?.” Emerging infections 2 (1998): 185-194. | Kahler, A.M., Hofstetter, J., Arrowood, M., Peterson, A., Jacobson, D., Barratt, J., da Silva, A.L.B.R., Rodrigues, C. and Mattioli, M.C., 2024. Sources and prevalence of Cyclospora cayetanensis in southeastern US growing environments. Journal of food protection, 87(7), p.100309. |
| Wurtz, Rebecca. “Cyclospora: a newly identified intestinal pathogen of humans.” Clinical infectious diseases 18.4 (1994): 620-623. | Casillas, S.M., Hall, R.L. and Herwaldt, B.L., 2019. Cyclosporiasis surveillance—United States, 2011–2015. MMWR. Surveillance Summaries, 68. |
| https://www.cidrap.umn.edu/foodborne-disease/cdc-cuts-back-foodborne-illness-surveillance-program | Markon, A.O., Karasick, A., Punzalan, C., da Silva, A.J. and Wolpert, B., 2024. Evaluating Foodborne Cyclosporiasis Using Foodborne Diseases Active Surveillance Network and Foodborne Disease Outbreak Surveillance System Data, 2015–2019. The American Journal of Tropical Medicine and Hygiene, 112(2), p.319. |
| https://www.cidrap.umn.edu/cyclospora/us-cyclospora-cases-mount-cdc-lags-tracking | Rehme, P., 2023. Notes from the field: doubling of cyclosporiasis cases partially attributable to a Salad Kit—Florida, 2021–2022. MMWR. Morbidity and Mortality Weekly Report, 72. |
| https://www.cdc.gov/foodnet/about/timeline.html | Shen, J., Cama, V.A., Jacobson, D., Barratt, J. and Straily, A., 2025. Cyclospora Genotypic Variations and Associated Epidemiologic Characteristics, United States, 2018–2021. Emerging infectious diseases, 31(2), p.256. |
| Chacín-Bonilla, L., 2010. Epidemiology of Cyclospora cayetanensis: A review focusing in endemic areas. Acta tropica, 115(3), pp.181-193. | |
| Ortega, Y.R. and Sanchez, R., 2010. Update on Cyclospora cayetanensis, a food-borne and waterborne parasite. Clinical microbiology reviews, 23(1), pp.218-234. | |
| Prabhukhot, G., 2025. Regulatory responses to foodborne illness outbreaks in the United States and their implications for food safety. Frontiers in Nutrition, 12, p.1717980. | |
| Hepatology, T.L.G., 2025. Foodborne pathogen surveillance cut by the CDC. The lancet. Gastroenterology & hepatology, 10(11), p.963.\ | |
| Henao, O.L., Jones, T.F., Vugia, D.J. and Griffin, P.M., 2015. Foodborne diseases active surveillance network—2 decades of achievements, 1996–2015. Emerging infectious diseases, 21(9), p.1529. | |
| CDC National Notifiable Diseases Surveillance System. July 4, 2026. Cyclosporiasis (week 26) Weekly cases* of notifiable diseases, United States, US territories, and Non-US Residents week ending July 4th, 2026. CDC Stacks. https://stacks.cdc.gov/view/cdc/258011 | |
| CDC NNDSS Annual Summary Data 2016-2023 Cyclosporiasis. https://wonder.cdc.gov/nndss-annual-summary.html | |
| Yang, M. 17 Apr 2025. FDA to suspend quality-control program for food testing due to staff cuts. The Guardian. https://www.theguardian.com/us-news/2025/apr/17/fda-suspends-quality-control-food-testing-staff-cuts | |
| Semuels, A. 8 Apr 2025. Food Safety Was Slipping in the US. Then Came Mass Layoffs. Time. https://time.com/7275746/food-safety-fda-layoffs/ | |
| Sun, L. 10 July 2026. Why we don’t know what food is spreading the parasite sickening thousands. Washington Post. https://www.washingtonpost.com/health/2026/07/10/why-we-dont-know-what-food-is-spreading-parasite-sickening-thousands/ | |
| Stobbe, M. 9 July 2026. Outbreak of diarrhea-causing parasite grows to more than 1,000 cases. Associated Press. https://apnews.com/article/cyclospora-outbreak-michigan-31e5e0034d39e85c844065a2bd593ecb |
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