U.S. Records Largest Cyclospora Outbreak Linked to Iceberg Lettuce Suppliers

The United States is experiencing its largest recorded outbreak of cyclospora, a single-celled parasite that causes watery diarrhea, nausea and fatigue. The Centers for Disease Control and Prevention (CDC) has confirmed 4,173 cases and is aware of an additional 7,400 state-reported cases since May 1, 2026. Historically the CDC averages about 2,800 cases per year, making this summer’s spike unprecedented.

Health officials say the parasite is transmitted through contaminated fresh produce, most commonly raw vegetables and herbs. A recent investigation traced a major cluster of at least 1,644 confirmed cases to shredded iceberg lettuce consumed in Michigan, Ohio, West Virginia, Indiana and Kentucky. The FDA’s trace-back identified Taylor Farms’ Mexican facility in Guanajuato as the likely source, and the company issued a voluntary recall of the affected lettuce.

Taco Bell, which used the same shredded lettuce in several locations, removed the product from its supply chain after the FDA’s findings were announced. The chain also adjusted its menu to offer lettuce-free options.

Public health experts advise consumers to wash produce under cold running water for at least one minute to reduce parasite load, though the only reliable method to eliminate cyclospora is cooking the food to an internal temperature of 158 °F (70 °C). Infected individuals can be treated with a ten-day course of antibiotics, and severe cases may lead to dehydration and require medical attention.

The outbreak comes amid recent reductions in federal food-borne disease surveillance. In 2025, the CDC’s dedicated cyclospora laboratory staff was cut from 11 to three personnel, and the Foodborne Diseases Active Surveillance Network (FoodNet) narrowed its mandatory monitoring to only salmonella and E. coli, removing cyclospora and several other pathogens from its core list.

"Routine outbreak investigators are the firefighters responding to a specific blaze. FoodNet is the citywide system that tracks how often fires occur and whether the overall risk is rising," said Daniel Jernigan, a former CDC official.

Officials continue to rely on state reports for case data while urging the public to stay informed about product recalls and to practice safe food handling.