U.S. Faces Record Cyclospora Outbreak, Health Officials Investigate Potential Sources
The United States is grappling with an unprecedented cyclospora outbreak, with 2026 already marking the highest number of reported cases in the nation’s history. According to state-level data, infections have surpassed those recorded during the previous peak in 2019.
As of July 9, 2026, the counties with the highest reported cases include Monroe with 215, Wayne with 160, and Washtenaw with 159. Michigan’s health department’s chief medical executive, Dr. Natasha Bagdasarian, noted, “Cyclosporiasis is not a new illness,” highlighting its common association with international travel. Currently, no specific source, such as a grower or produce type, has been pinpointed, though contamination during growth or processing phases remains a possibility. Heating food to at least 158°F is known to kill Cyclospora, according to the Michigan Department of Health and Human Services.
Over 30 states have reported infections this year, already exceeding the 4,700 cases registered in 2019. Though the illness typically isn’t life-threatening, it is treated with antibiotics. Federal health officials indicate that infection patterns may differ across regions, though cases in states like Michigan, Ohio, Kentucky, and West Virginia appear connected.
Potential Culprit: Lettuce in Michigan
In Michigan, where over 3,300 cases have been reported, health authorities suspect lettuce or salad greens as potential sources. After interviewing more than 1,000 patients, lettuce appeared frequently in their investigations, as stated by Bagdasarian. Consequently, Michigan residents are advised to purchase whole heads of lettuce, discard outer layers, and thoroughly wash the remaining leaves. Bagged lettuce and pre-mixed salad kits are to be avoided.
Taco Bell has proactively removed select ingredients from some locations as a precaution and stated, “We will continue to closely monitor the situation and follow the guidance of public health authorities.” Officials from the Food and Drug Administration are investigating multiple produce items and locations reported by infected individuals.
Understanding Cyclospora Infections
Cyclospora, a microscopic parasite, causes watery diarrhea with frequent, sometimes explosive, bowel movements, as per the U.S. Centers for Disease Control and Prevention (CDC). Outbreaks are most common in late spring and summer. The parasite spreads through feces, often infecting people via contaminated fruits or vegetables irrigated with tainted water.
The prevalence of cyclospora has increased over the past decade, with significant spikes in 2018 and 2019. Experts attribute this rise to improved detection methods and climate change. The infection rate in 2019 was the highest on record, with about 4,700 cases, according to federal data.
The CDC recently issued a health alert detailing 1,645 confirmed domestic cases since May 1, with over 5,100 requiring further analysis. Reports come from 34 states, though no deaths have been reported. The true case count is likely higher due to unreported mild cases. Expecting numbers to rise through August, CDC’s Gwen Biggerstaff noted that exposure timing remains uncertain.
The CDC’s ongoing investigation includes cases in Michigan, Ohio, Kentucky, and West Virginia, though it’s unclear why these states are linked. Michigan has logged over 3,300 cases, with additional reports from Ohio, New York City, and Illinois.
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