U.S. cyclosporiasis cases surge to 4,173 confirmed, linked to Taylor Farms lettuce

The United States has reported a sharp rise in cyclosporiasis cases since May 2026, with 4,173 laboratory-confirmed cases across 41 states and over 7,400 additional cases under investigation as of mid-July. The outbreak, caused by the microscopic parasite Cyclospora cayetanensis, has resulted in 308 hospitalizations and no reported deaths. Federal health authorities have linked a multistate cluster involving five states—Indiana, Kentucky, Michigan, Ohio, and West Virginia—to shredded iceberg lettuce supplied by California-based Taylor Farms to Taco Bell restaurants.

The Centers for Disease Control and Prevention and Food and Drug Administration conducted traceback investigations that repeatedly traced contaminated lettuce back to Taylor Farms' operations in central Mexico. On July 17, federal officials publicly identified the connection and advised consumers to avoid shredded iceberg lettuce at Taco Bell locations in the five affected states. Taylor Farms subsequently issued a voluntary recall of iceberg lettuce sourced from central Mexico, initially distributed to 27 states. The company stated that the recall targeted products produced between June 29 and July 16, noting that other Taylor Farms products remained unaffected.

On Saturday, July 18, the FDA reported that a lettuce sample had tested positive for cyclospora. However, the agency reversed this finding on Sunday, July 19, stating that laboratory experts had determined the result was a false positive and did not represent true amplification. As of Sunday, the FDA reported no confirmed positive sample results for cyclospora, though the agency emphasized that traceback investigations and epidemiological data continue to support the recall. The investigation remains ongoing, with federal officials noting that additional sources or distribution channels may be identified.

Cyclosporiasis typically begins one to two weeks after exposure and causes watery diarrhea, loss of appetite, stomach cramps, nausea, fatigue, and sometimes vomiting. Unlike some foodborne illnesses, the parasite does not typically spread directly from person to person and requires one to two weeks in the environment to become infectious. The illness is generally treated with antibiotics and is not usually life-threatening, though dehydration poses a risk during summer months. Case numbers peak in spring and summer, with the CDC defining the U.S. cyclosporiasis season as May 1 through August 31.

The outbreak has had significant economic impacts. Restaurant chains with lettuce-heavy menus experienced notable declines in foot traffic following news of the outbreak. Sweetgreen shares fell 23 percent in early trading before recovering after the Taco Bell link was confirmed. Taco Bell itself saw foot traffic drops exceeding 18 percent after federal identification, while other salad chains including Chopt, Chipotle, and Panera Bread also reported decreased customer visits. The outbreak has been attributed partly to systemic challenges in disease surveillance, with experts noting that federal workforce reductions have affected outbreak response capacity and the Foodborne Diseases Active Surveillance Network's monitoring capabilities.