Michigan warns of leafy greens in cyclosporiasis outbreak as cases surge

Michigan had 2,640 cyclosporiasis cases by July 13, with the sharpest increase clustered in Southeast Michigan. Michigan health officials warned restaurants and commercial kitchens to handle raw produce more cautiously as the outbreak kept growing, and investigators had not identified a single produce grower, supplier or produce type as the source, but early interviews kept pointing back to lettuce and salad greens.

The Michigan Department of Health and Human Services told food preparers to buy whole heads of lettuce instead of prewashed bagged lettuce or salad mixes, throw away the outer leaves, and wash the inner leaves under running water. For leafy greens that can be cooked, cooking is the safest option. It also warned that cilantro, basil, green onions, raspberries and snow peas could carry risk, with raspberries singled out as especially hard to clean. Freezing may reduce Cyclospora, the parasite that causes the illness, but it does not guarantee elimination.

Michigan normally records about 40 to 50 cases a year. MDHHS said more than 1,000 interviews had been completed in Michigan. Dr. Natasha Bagdasarian, Michigan’s chief medical executive, said early information showed lettuce repeatedly coming up as a common product in interviews, but investigators were still not certain of the exact source. The Centers for Disease Control and Prevention counted 843 confirmed cases and more than 1,500 suspected cases as of July 9. Food Safety News' tally put the outbreak in 31 states, including 364 cases in Ohio and 470 in New York.

Michigan officials also said recreational water exposure, including swimming in lakes, was not a recognized risk factor and that there was no evidence linking those activities to the outbreak. Cyclospora typically causes watery diarrhea, nausea and stomach cramps, and symptoms can take up to two weeks to appear after exposure.