Cyclospora Outbreak Across Multiple States Raises Food Safety Concerns Over Salad Greens

A parasitic outbreak causing prolonged diarrhea has expanded to more than 7,000 confirmed or suspected cases across 34 states, with investigation pointing toward contaminated salad greens and lettuce as the likely source. The outbreak of cyclospora—a microscopic parasite that causes severe intestinal illness—has prompted federal and state health authorities to issue warnings about fresh produce consumption, particularly in affected regions.

Scale of the Outbreak

The cyclospora outbreak has hit the Midwest particularly hard, with more than 4,000 cases documented in Michigan and Ohio alone, according to state health officials. Additional cases have been linked in West Virginia and Kentucky. The broader national count, tracked by the Centers for Disease Control and Prevention since May 1, encompasses 34 states, though the exact geographical spread across all affected regions remains unclear. So far, approximately 1 in every 11 cases has required hospitalization, but no deaths have been reported.

Investigation and Food Source

Michigan health officials have focused their investigation on lettuce and salad greens as potential culprits, though they have cautioned that other fresh produce cannot be ruled out. Critically, no specific type of lettuce, grower, or supplier has been identified as the source, complicating efforts to isolate and remove contaminated products from supply chains. Federal health authorities have emphasized the importance of staying informed about alerts and maintaining standard food safety practices, particularly washing produce thoroughly before consumption.

Dr. Nuwan Gunawardhana, a hospital epidemiologist specializing in infectious diseases at Columbia University Irving Medical Center, explained that cyclospora is a particularly hardy organism with strong adhesive properties. The parasite attaches firmly to fresh produce surfaces and is not typically spread from person to person, making foodborne transmission the primary concern during outbreaks.

Symptoms and Risk Groups

Cyclosporiasis—the intestinal infection caused by cyclospora—develops between two days and two weeks after exposure. Affected individuals experience prolonged watery diarrhea, stomach cramps, nausea, fatigue, loss of appetite, and weight loss. If left untreated, the illness can persist for weeks and lead to severe dehydration. A combination antibiotic can treat the infection, though treatment delays allow the parasite to cause extended suffering.

Young children, elderly individuals, and immunocompromised people face heightened risk of severe disease. In most healthy adults, symptoms tend to remain mild, though discomfort and lost productivity remain significant.