Foodborne Parasite Cyclospora Sickens Hundreds Across U.S.
Editor's note: This story has been edited to include the latest outbreak updates, listed chronologically at the bottom of the article.
Cases of cyclosporiasis are surging across the U.S. this summer, with federal and state public health officials together reporting more than 700 cases of Cyclospora cayetanensis infection since May 2026.
Past foodborne cyclosporiasis outbreaks reported in North America have been linked to produce items including bagged salad mixes and kits, fresh herbs, raspberries, snow peas, and green onions.
Michigan Reports 572 Cases in Addition to CDC’s 145
The Michigan Department of Health (MDOH) alone has reported 572 cyclosporiasis cases within the state since late June, with counties in Southeast Michigan the most affected. For comparison, in a typical year, Michigan reports approximately 50 Cyclospora infections.
According to the latest figures (current through June 16) from the U.S. Centers for Disease Control and Prevention (CDC), an additional 145 cases of cyclosporiasis have been reported in 17 states—not including Michigan—since May 1. These cases have not yet been associated as part of a larger outbreak by CDC. Investigations to identify potential clusters and potential sources of illness are ongoing.
The Growing Prevalence of Cyclospora
Since the 1990s, the prevalence of Cyclospora cayetanensis has had an upward trajectory, trending toward possible endemicity. As explained by expert Larry Keener, CFS, PA in Food Safety Magazine, domestic cases of Cyclospora infections more than doubled from 537 in 2016 to 1,194 in 2017, and then nearly tripled to 3,519 cases in 2018. Between 2019 and 2022, the number of laboratory-confirmed cases of cyclosporiasis in the U.S. ranged from a high in 2019 of 2,408 cases to a low in 2021 of 1,024 cases. By 2023, there were nearly 3,000 cases of cyclosporiasis reported in the U.S.
Cyclosporiasis is now considered an "important neglected parasitic infection" by CDC. It is also a nationally notifiable disease.
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Update, July 8, 2026: According to a CDC email uncovered by CNN, federal officials have been investigating several clusters of cyclosporiasis in Illinois, New York City, New York State, Pennsylvania, and Texas, which have suspected links to Mexican-style restaurants, a grocery chain, and a catered event. Additional cyclosporiasis clusters have been identified in Alabama, Kentucky, Michigan, Ohio, Tennessee, Virginia, and West Virginia. Investigations are ongoing with patient interviews underway.
At the state level, the number of Michigan cases is reportedly up to 681 since June 22. Ohio has also reported 177 cyclosporiasis cases since the beginning of the year, with 171 occurring in June alone, mostly since June 20. New York State (outside of New York City) has seen 112 cases in 2026, with 107 reported since May 1.
Meanwhile, FDA's Coordinated Outbreak Response and Evaluation (CORE) network is conducting traceback investigations on white and green onions, cucumbers, and cilantro to narrow down the list of potential transmission vehicles. Today, the agency added two Cyclospora outbreak investigations (one with seven cases and one with 18 cases) to its CORE table. Neither has been linked to a food source yet.
Update, July 10, 2026: MDOH has reported 1,251 cases of cyclosporiasis since June 22, resulting in 44 known hospitalizations. Monroe, Wayne, and Washtenaw counties (in the southeastern part of the state) are the most affected, with 215, 160, and 159 cases, respectively.
CDC has still not updated the publicly available data on national cyclosporiasis incidence.
