Michigan health officials have identified lettuce and salad greens as the likely source of a widespread cyclosporiasis outbreak across the U.S.
The identification of a specific food source is critical for stopping the spread of the parasite and preventing further illnesses during a record-breaking year for infections.
According to the Michigan Department of Health and Human Services, "Lettuce or salad greens could be the source of illnesses in the state," officials said [1]. The parasite, known as Cyclospora, causes prolonged watery diarrhea and other gastrointestinal distress. Health experts said that if a person ingests contaminated food, they may experience weeks of watery diarrhea and "frequent and sometimes explosive bowel movements" [5].
The scale of the 2026 outbreak is unprecedented. More than 30 states have reported infections this year [4], and thousands of people have been sickened across much of the country [3]. Officials said that 2026 has already become the worst year on record for reported cyclospora cases in the U.S. [4].
State officials in Michigan are continuing to investigate the supply chain to pinpoint the exact origin of the contamination. A state health spokesperson said, "The picture is getting clearer on what could be causing the state's massive cyclosporiasis outbreak" [2].
While officials have narrowed the source to leafy greens, the investigation remains ongoing to determine if the contamination is limited to specific brands or regions. Public health agencies continue to monitor reports from other states to coordinate a nationwide response to the surge in cases.
“"Lettuce or salad greens could be the source of illnesses in the state,"”
The identification of lettuce and salad greens as the primary vectors suggests a systemic failure in the agricultural supply chain or contamination at the source. Because Cyclospora is a hardy parasite that can survive various washing processes, this outbreak highlights the difficulty of regulating fresh produce. The record-breaking number of cases in 2026 may indicate either an increase in the prevalence of the parasite in farming regions or improved diagnostic reporting across the 30 affected states.
