Outbreak of diarrhea-causing parasite grows to more than 1,000 cases
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- Michigan reported 992 cyclospora cases as of Wednesday with about 40 hospitalizations—roughly twenty times its typical annual count of about 50—making it the largest outbreak in state history since cases began appearing on June 22.
- Lucas County, Ohio reported 306 cases as of Wednesday, with Northwest Ohio totaling more than 500 cases; 28 other states are also investigating similar illnesses, and no deaths or contamination source have been identified.
- The CDC says its national case total is four times higher than at the same point last year but cautions it's not yet clear how unusual this year will be, and notes no evidence the parasite has become more infectious.
- Past major U.S. cyclospora outbreaks include a 1997 Guatemalan raspberry outbreak that sickened over 1,000 and a 2019 Mexican basil outbreak that sickened more than 2,400; experts attribute rising case counts to climate change and better detection.
- Cyclospora can stick to produce in ways washing can't fully eliminate, prompting Michigan health officials to recommend buying whole heads of lettuce rather than prewashed bagged mixes and removing the outer two to three leaves before washing.
Why it matters: Michigan's cyclospora caseload of 992—roughly twenty times its usual annual tally—comes with no identified source and no deaths, yet the CDC's national count is running four times last year's pace. For consumers in affected regions, the prevention guidance is unusually specific: skip prewashed bagged lettuce and strip outer leaves.
