US federal health officials have identified shredded iceberg lettuce imported from Mexico and served at Taco Bell restaurants as a source of Cyclospora, the parasite behind a nationwide surge in cases of severe, watery diarrhoea. A traceback investigation by the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) traced the contaminated lettuce to a single Mexican supplier, reportedly Taylor Farms, which was also linked to a 2024 multi-state E. coli outbreak tied to onions served at McDonald's. Authorities are now urging consumers to avoid iceberg lettuce at Taco Bell outlets in the affected states, while stressing that lettuce sold in shops or served elsewhere is not currently implicated.

The affected restaurants are located in Indiana, Kentucky, Michigan, Ohio and West Virginia. Cyclosporiasis cases have now been reported across 34 states, with the CDC recording 1,645 laboratory-confirmed cases nationally, including 141 hospitalisations, though local health departments report considerably higher figures once probable cases are included. Michigan has been especially hard hit, logging 5,002 cases and 102 hospitalisations as of 17 July.