Cyclospora Outbreak Continues to Spread

An outbreak of the parasite cyclospora has led to more than 4,000 reported cases and 80 hospitalizations in more than 30 states so far, with more than 3,000 cases across Michigan and Ohio alone, and an ongoing investigation suggests lettuce or salad greens may be the source, reported CNN this week.

However, Michigan health officials noted that other foods cannot be ruled out and no specific type, grower or supplier has been identified as the source of the outbreak.

“Early information has shown lettuce as a common product that regularly comes up during the investigation,” Dr. Natasha Bagdasarian, Michigan’s chief medical executive said.

Michigan reported 2,640 cases as of 9:30 a.m. Monday, including 44 hospitalizations. Ohio has reported 361 cases since June 1. At least 46 people have been hospitalized.

The parasite typically spreads when traces of infected human feces contaminate a water source that is used to irrigate or clean produce, which people then eat, said Don Stoeckel, an environmental biologist and special projects lead at Cornell Produce Safety Alliance to The Washington Post.

Health officials are also investigating the potential that Taco Bell restaurants are part of the outbreak, The Washington Post reported.

“Public health officials have not confirmed a link to Taco Bell or any specific ingredient, supplier, restaurant or retailer. While authorities continue their broader review, Taco Bell has voluntarily and temporarily removed limited ingredients at select restaurants as a precautionary measure,” said the QSR in a statement.

Past U.S. outbreaks have been tied to contaminated basil, cilantro, mesclun lettuce, raspberries and snow peas. These items are generally imported, often eaten raw, tough to wash well and have a short shelf life.

This year is “on track to be the biggest year on record” for cyclosporiasis in the United States, according to The New York Times.

“Given the previous link with lettuce and salad greens and the early signs that they may be causing illness in Michigan, health officials there issued specific guidance for preparing the greens. Instead of buying bagged or pre-mixed salad kits, they recommended using whole heads of lettuce, discarding the outer two to three layers of leaves and then washing the inner leaves thoroughly under running water,” wrote the Times.

The Centers for Disease Control and Prevention (CDC) said on its website that it is aware that states are likely to report higher case counts of cyclosporiasis than reflected in CDC data and is working closely with states to update numbers as additional cases are confirmed. Since May 1, 2026, the CDC has received reports of 1,645 confirmed domestic cases of cyclosporiasis and is aware of more than 5,100 cases that require further analysis to confirm the illness as domestically acquired cyclosporiasis. So far this year, multiple states have reported an increase in cases compared to the same period in 2025.

Food safety