Editor's note: This story has been edited to include the latest outbreak updates, listed chronologically at the bottom of the article. Alternatively, you can read the most recent coverage here. Notably, as of July 20, Michigan and Ohio are reporting more than 6,000 and 2,000 cases, respectively.

More than 1,600 people have been sickened in a five-state cyclosporiasis outbreak. Iceberg lettuce supplied by Taylor Farms of Mexico to companies like Taco Bell and Walmart has been identified as the vehicle of infection by the U.S. Food and Drug Administration (FDA).

As of July 16, FDA and the U.S. Centers for Disease Control and Prevention (CDC) report 1,644 people infected with Cyclospora cayetenensis in association with the outbreak in Indiana, Kentucky, Michigan, Ohio, and West Virginia. These patients fell ill between May 13 and July 13, 2026, and reported exposure to Taco Bell. There have been 94 hospitalizations.

Meanwhile, as of July 16, the Michigan Department of Health and Human Services (MDOH) reports 5,002 cyclosporiasis cases and 102 hospitalizations in the state alone. Additionally, Michigan officials have analyzed food exposure details from 190 of the CDC-confirmed outbreak cases and found that 90 percent of those interviewed reported eating iceberg lettuce at Taco Bell.

Taylor Farms Product Distribution and Recall Information

On July 17, FDA announced that its traceback investigation identified Taylor Farms of Mexico as the single supplier of implicated iceberg lettuce products to Taco Bell locations where sick people fell ill. Taylor Farms announced a voluntary recall, which includes iceberg lettuce products sold at Walmart stores in 15 states under the Marketside brand. Taco Bell has also confirmed it is no longer using lettuce supplied by Taylor Farms of Mexico.

Taylor Fresh Foods, parent company of Taylor Farms, issued a statement on July 17 saying that FDA’s traceback points to "a specific independent farm that represents less than 1 percent of the U.S.'s iceberg lettuce supply as the potential source of the outbreak." The company also specified that no Taylor Farms-branded salads or kits—which do not contain iceberg lettuce—are associated with the outbreak.

Recalled products were distributed by Taylor Fresh Foods and sold in Walmart stores under the Marketside brand between June 29 and July 16 in a total of 28 states: Alabama, Arkansas, Connecticut, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Michigan, Mississippi, Missouri, North Carolina, New Hampshire, New Jersey, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, Wisconsin, and West Virginia.

FDA Withdraws Positive Lettuce Sample Finding, But Does Not Negate Other Evidence

Interestingly, on July 18, FDA reported that a sample of lettuce supplied by Taylor Farms had tested positive for C. cayetenensis, but on July 19, the agency said this finding was more likely a false positive. “Due to the complexity in detection of Cyclospora, FDA laboratory experts re-reviewed the sample results and have concluded that the finding does not represent true amplification and should be considered a false positive,” the agency said. Although there are currently no confirmed positive product sample results, lettuce supplied by Taylor Farms of Mexico is still considered to be the source of the outbreak, and FDA is working with the firm to remove implicated product from the market.

On July 19, Taylor Farms issued another statement (which the company has since taken down), saying, “Today, FDA apologized to us. Yesterday, FDA informed Taylor Fresh Foods that one of its iceberg lettuce products from central Mexico tested positive for Cyclospora. Today, we were informed that FDA made a mistake, and this was a false positive. To be clear, at this moment, FDA has not identified a single positive product test result for Cyclospora.”

However, FDA still considers Taylor Farms lettuce to be the source of the outbreak based on the strong traceback and epidemiological evidence. The existing recall still stands and is limited to iceberg lettuce grown and processed in central Mexico.

Alex Sundermann, Dr.P.H., Assistant Professor of Epidemiology at the University of Pittsburgh, explained to Food Safety Magazine why the false positive result does not cast doubt on Taylor Farms' implication in the outbreak.

"Outbreak investigations rely on a toolkit, and epidemiology and environmental sampling are two different tools that answer two different questions. Epidemiology asks: who got sick and what did they have in common? That evidence, gathered by public health investigators, pointed clearly to lettuce from a single supplier well before FDA ever collected a sample," Dr. Sundermann said.

He continued, "Environmental sampling asks something narrower: is the pathogen present in this specific piece of food at this specific moment? A positive can help confirm a source, but a negative doesn't clear one. It just means the pathogen wasn't detected in that sample or at that time. Given that Cyclospora can't be cultured and this sample was taken weeks after implicated lettuce was already consumed, a negative here is not surprising and not exonerating. The epidemiologic and traceback evidence haven't changed."

Given the difficulty of testing for C. cayetenensis, traceback evidence is especially imperative in the current outbreak. “Events like this underscore why traceability and supply chain visibility are essential to food safety," Michelle Covey, Vice President of Customer Success at GS1 US, told Food Safety Magazine. "During an outbreak, investigators need reliable, consistent data to quickly connect products, lots, locations, and movement through the supply chain."

Addressing Confusion About Differing Numbers From Michigan, CDC

Because the number of cyclosporiasis cases seen across the U.S.—and especially in Michigan—has been elevated in comparison to previous summers, and because an official outbreak cluster had not been announced until a July 14 health advisory from CDC, consumers and media have looked to several federal and state sources for data to try to understand the situation, causing public confusion.

The 5,000-plus case count from MDOH differs from the official 1,664 cases reported by CDC because all those who fell ill in Michigan may not be part of the outbreak, or some cases may still be under investigation to determine whether they are. Additionally, 2026 national surveillance numbers reported by CDC track laboratory-confirmed cases in the U.S. overall, which include this outbreak as well as illnesses that are not a part of this outbreak. As of July 13, this number includes 1,645 cases across 34 states. Per CDC, “Multiple jurisdictions have reported an increase of cases compared to the same period in 2025. [The agency assumes] a six-week reporting lag between illness onset and case reporting to CDC; therefore, [the agency anticipates] that case counts will continue to rise as data are received.”

In a July 16 briefing hosted by George Washington University's Institute for Food Safety and Nutrition Security, food science and consumer advocacy experts explained how the complexity of the foodborne illness surveillance system across the U.S. leads to federal–state reporting lags, especially as a worsening lack of resources strains the system. Additionally, the biology of C. cayetenensis, including its long incubation period and diagnostic testing limitations, presents unique challenges related to the identification of infections and clusters of cases. They also discussed the difficulty of disseminating public health information amid uncertainty, and the consequences such uncertainty has on consumer confidence and safety.

U.S. Cyclosporiasis Reports Increase Year After Year

Since the 1990s, the prevalence of C. cayetanensis has had an upward trajectory, trending toward possible endemicity. As explained by expert Larry Keener, CFS, PA in Food Safety Magazine, domestic cases of Cyclospora infections more than doubled from 537 in 2016 to 1,194 in 2017, and then nearly tripled to 3,519 cases in 2018. Between 2019 and 2022, the number of laboratory-confirmed cases of cyclosporiasis in the U.S. ranged from a high in 2019 of 2,408 cases to a low in 2021 of 1,024 cases. By 2023, there were nearly 3,000 cases of cyclosporiasis reported in the U.S.

In the July 16 GWU IFSNS briefing, Craig Hedberg, Ph.D., Professor in the Division of Environmental Health Sciences at the University of Minnesota, suggested that the year-over-year increase in reported Cyclospora infections in the U.S. could, in part, be a result of improved diagnostic testing; specifically, the growing use of culture-independent diagnostic tests (CIDTs), which make the clinical identification of cyclosporiasis more likely.

Update, July 21, 2026: As of July 20, Michigan reports 6,571 cyclosporiasis infections and Northwest Ohio has seen 2,029 cases. Read more.