Michigan’s cyclosporiasis outbreak continues to expand, with state health officials confirming 6,571 cases as of July 21, 2026, marking a steady climb that has alarmed public health experts across the Midwest. The Michigan Department of Health and Human Services reported the new total on July 21, up from 6,148 cases the day before, with illnesses tracked back to June 22. Of the reported cyclosporiasis infections, 102 patients had been hospitalized as of July 16.
The counties hit hardest by the cyclosporiasis surge remain concentrated in southeastern Michigan. Monroe, Lenawee, Washtenaw, Wayne, Shiawassee, Jackson, Oakland and Livingston counties continue to report the highest case counts in the state. Nationally, the picture is just as concerning. The CDC has identified cyclosporiasis cases in 34 states and expects the numbers to keep climbing through the end of August, when the typical Cyclospora season winds down.
Michigan’s cyclosporiasis total is notably higher than the federal count, a discrepancy officials attribute to reporting lags. The CDC, yet to update its own figures since July 14, reported just over 1,644 confirmed, domestically acquired cyclosporiasis cases spread across five states — Michigan, Ohio, West Virginia and Indiana — among patients who fell ill after May 13, 2026.
State totals tend to run higher than the CDC’s because states often count both probable and confirmed cyclosporiasis cases, and there’s typically a delay before the CDC formally links a case to the broader outbreak. Ohio has also been swept up in the same cyclosporiasis cluster, with Northwestern Ohio health officials separately reporting 2,029 cases as of the same date, bringing the combined Michigan-Ohio total past 8,000.
The scale of this year’s cyclosporiasis outbreak stands out even against a backdrop of rising cases nationally. Domestic Cyclospora infections had already been trending upward for decades, climbing from 537 cases in 2016 to nearly 3,000 by 2023, but 2026’s numbers surpass even that trajectory — the U.S. had logged only 249 confirmed domestically acquired cases by this point in 2025, meaning this year represents roughly a 560 percent jump.
Some researchers point to gaps in the nation’s disease-surveillance infrastructure, while others suggest improved testing is simply catching more cyclosporiasis cases that would have gone undiagnosed in the past. A few experts have also floated a climate connection, theorizing that longer, hotter summers could be extending the parasite’s active season.
Investigators believe they have traced the source of the outbreak. FDA traceback work has pointed to iceberg lettuce grown in central Mexico and supplied by Taylor Farms of Mexico, distributed through parent company Taylor Fresh Foods to 28 states. Taylor Farms has since issued a voluntary recall, and downstream retailers that received the implicated lettuce include Taco Bell, which has since dropped Taylor Farms as a supplier, along with Walmart.
Michigan’s own investigation supports the lettuce theory: state officials reviewed food-exposure details from 190 CDC-confirmed cases and found that 90 percent of those interviewed had eaten iceberg lettuce at Taco Bell.
Notably, a scare over a specific lettuce sample has since been retracted. Federal officials had initially flagged a Taylor Farms iceberg lettuce sample from central Mexico as testing positive for cyclospora, but have since called that result a “false positive.”
In the meantime, health officials are urging residents to take precautions. The Michigan Department of Health and Human Services recommends buying whole heads of lettuce instead of pre-washed or bagged salad kits, discarding the outer two to three leaf layers, thoroughly washing the remaining inner leaves, and, when possible, cooking greens to at least 158 degrees Fahrenheit, since the parasite resists routine washing and chemical disinfection.
Anyone experiencing sudden or ongoing diarrhea is urged to contact their health care provider and local health department, as the cyclosporiasis outbreak shows no signs of slowing before its seasonal end this summer.
