Four Warren County residents have tested positive for cyclosporiasis, a parasitic intestinal illness tied to recalled iceberg lettuce from Taylor Farms, according to the Ohio Department of Health.

The cases are part of a statewide outbreak that has prompted the U.S. Centers for Disease Control and Prevention to deploy disease investigators to Ohio for a three-week assignment. Ohio has reported 2,574 total cases, with more than 90% occurring after June 20, the Ohio Department of Health reported Friday.

Neighboring counties are also affected. Montgomery County has 27 confirmed cases, Greene County has nine, and Butler and Clark counties each have eight, according to ODH data released the same day.

What triggered the recall

Taylor Farms de Mexico issued a voluntary recall on Thursday, July 17, of all iceberg lettuce sourced from central Mexico. The recalled products were distributed between June 29 and July 16 across 27 states, including Ohio, and reached Taco Bell restaurants, Walmart stores, Jack in the Box locations and food service distributors Sysco and US Foods.

The FDA's traceback investigation points to shredded iceberg lettuce from Taylor Farms growers in central Mexico as the outbreak source, the agency said Thursday.

Taco Bell said it completed removal of the affected lettuce from all its restaurants nationwide on July 17. The chain has since stopped using Taylor Farms de Mexico lettuce entirely. Foot traffic at Taco Bell locations nationwide dropped more than 30% on July 17 compared with the chain's average Friday traffic earlier in 2026, according to location analytics firm Placer.ai.

Taco Bell CEO Sean Tresvant wrote on LinkedIn: "We aren't entitled to your loyalty. We earn it one meal at a time."

No public data confirms which specific Mason or Deerfield Township Taco Bell locations received the recalled lettuce. The FDA has noted that not every Taco Bell in the five initial outbreak states received product from the supplier.

Taylor Farms' response

Taylor Farms temporarily suspended all production at its central Mexico facility as of Saturday, July 18, and commissioned independent experts to review food safety processes there, the company said in a Thursday statement. The company says it invests more than $200 million annually in food safety protocols.

Brian Ronholm, Consumer Reports' director of food policy, said Thursday that the information Taylor Farms released is "vague and inadequate, especially given the gravity of this outbreak."

What the CDC team will do

CDC disease detectives will interview people who tested positive, collect exposure histories, identify clusters and coordinate with federal teams on multi-state tracing, the agency said. The deployment was requested through the CDC's Epi-Aid program, which dispatches Epidemic Intelligence Service officers to investigate urgent public health problems.

What residents should know

Cyclosporiasis causes intestinal illness marked by frequent, sometimes explosive bowel movements. The CDC advises that washing produce does not kill the Cyclospora parasite. Cooking lettuce to at least 158 degrees Fahrenheit will kill it. Consumer Reports food safety experts recommend that residents in the 27 distribution states, including Ohio, discard all iceberg lettuce as a precaution.

The CDC said the team's three-week assignment will keep investigators in Ohio through approximately mid-August.