Cyclospora outbreak map: See the states affected by the diarrhea parasite — and which have the most cases

• Michigan has reported the most cases of cyclosporiasis during the ongoing outbreak.
• Cyclosporiasis is spread through contaminated food and water, and causes symptoms including diarrhea.
• We made two maps to show the states with the most reported cases, and where food has been recalled.

The Midwest remains the hotspot of an outbreak of cyclosporiasis, a parasitic infection that can trigger weeks of watery diarrhea.

At least 11,276 cases of cyclosporiasis have been reported across 46 states in 2026, according to Georgetown University's Health Security Operations Center, which is tracking state and national-level data.

There are a number of potential sources of confusion in this outbreak, including differing state and federal case counts, and how the FDA and Taylor Farms have shared information on the suspected source of infections.

In contrast to Georgetown's count, the CDC said in its latest cyclosporiasis update on July 15 it had confirmed 1,645 domestic cases of cyclosporiasis, and was aware of more than 5,100 cases that need further analysis to confirm. Some state health departments are tallying cases as part of the ongoing outbreak, while others include all cases reported in 2026 in their figures. According to the CDC, the typical cyclospora season lasts until late August, and cases could continue to rise until then.

The states with the most known cases of cyclosporiasis include Michigan and Ohio

Overall, data shows that the bulk of cases have been identified in the Midwest and mid-Atlantic states, as seen in the map below.

Katelyn Jetelina, assistant professor adjunct of epidemiology at Yale School of Public Health, wrote in her public health newsletter, Your Local Epidemiologist, on July 21 that several outbreaks are running at once, including one suspected to be caused by cilantro in New York. She described the Midwest outbreak as "its own beast" that wasn't yet slowing down.

On Friday, Taylor Farms voluntarily recalled iceberg lettuce from the US that was sourced from central Mexico, as shown below.

Taylor Farms told shoppers who had bought iceberg lettuce distributed June 29th through July 16th in the following states should not consume it and throw it out: Alabama, Arkansas, Connecticut, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Michigan, Missouri, Mississippi, North Carolina, New Hampshire, New Jersey, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, and Wisconsin.

The FDA said in an update to its website Sunday: "Do not eat recalled iceberg lettuce from Taylor Farms de Mexico. FDA's investigation is ongoing."

However, other foods can't be ruled out.

(As Business Insider's Dan DeFrancesco explained in Tuesday's edition of the Business Insider Today newsletter, the situation is a little more complex than we get into here.)

Jetelina said iceberg lettuce was recalled in 27 states "due to a combination of the complexity of food distribution networks and continued uncertainty around where people are most impacted."

Posing the question, "When will this end?" Jetelina said, "No one knows. Either the contaminated food works its way out of circulation, or it takes a few weeks, the temperatures get cool, and the parasites no longer mature on produce (basically killing themselves off). It's hard to tell from the data alone if this outbreak is coming to a close given that it's significantly delayed."

How to avoid Cyclospora

Cyclospora spreads through contaminated food and water, and symptoms, including watery diarrhea, nausea, and stomach cramps, can take up to two weeks to show, making it difficult to trace back to a definitive source. The parasite is resistant to disinfectants, and washing food doesn't guarantee its removal, as it is particularly good at sticking to produce.

Health authorities say in order to definitively kill the parasite, cook foods to at least 158 degrees Fahrenheit. Buying whole heads of lettuce and peeling back the outer layer of leaves rather than choosing pre-washed, bagged, or pre-mixed salads is also a good move, if you are more risk-tolerant.

If you enjoyed this story, be sure to follow Business Insider on MSN.