Michigan health officials have urged consumers to avoid prepackaged salads and take specific precautions when handling lettuce amid an ongoing cyclosporiasis outbreak. The state has reported 2,640 cases of the illness, part of a larger national outbreak affecting nearly 3,000 people across 31 states, with 86 hospitalizations linked to the disease.

State health authorities have not yet identified a definitive source of contamination but have highlighted lettuce as a common factor in early investigative findings. "Early information has shown lettuce as a common product that regularly comes up during the investigation," said Natasha Bagdasarian, chief medical executive of the Michigan Department of Health and Human Services. However, officials emphasized that there is not enough information to pinpoint the specific type of produce, grower, or supplier responsible, and other food items cannot be ruled out as potential sources.

To reduce the risk of infection, Michigan health officials have issued a series of food safety recommendations. Consumers are advised to avoid prepackaged salads entirely. Instead, they should opt for individual heads of lettuce, discard the outer layers, and rinse the remaining lettuce thoroughly under running water. Officials also recommended cooking vegetables when possible, as heat can destroy the parasite that causes cyclosporiasis.

Cyclosporiasis is a parasitic illness caused by infection with Cyclospora cayetanensis, a pathogenic apicomplexan protozoan. Symptoms typically develop about a week after exposure and can include watery diarrhea that is sometimes uncontrollable, unusually bad gas, stomach cramps, nausea, severe fatigue, and body aches—symptoms often resembling the flu. Dehydration is a serious complication of the illness, particularly in vulnerable populations.

The disease can be treated with fluids to prevent or address dehydration and a specific antibiotic regimen. While most people recover with treatment, the illness can persist for weeks or even months if left untreated. Public health guidance focuses on both treatment and preventive measures, especially given the challenges in tracing the contamination source during large, multi-state outbreaks.

Why It Matters

This outbreak represents one of the largest cyclosporiasis incidents in recent U.S. history, with Michigan accounting for the majority of national cases. Past outbreaks, including a 1996 incident linked to imported raspberries, have demonstrated how difficult it can be to trace and contain foodborne Cyclospora infections, which often involve imported fresh produce and complex supply chains.

Because symptoms can take up to a week to appear and mimic other gastrointestinal illnesses, underreporting is common, and case counts may not fully reflect the outbreak’s scope. The current advisory aims to protect consumers while investigators continue to analyze case data and product distribution patterns to identify the contamination source.