Infections from the diarrhea-causing parasite cyclospora are surging, with 2026 already the nation's worst year for reported cases. More than 30 states have reported infections this year, and current data from them shows the number of infections surpassing the record U.S. mark of about 4,700 set in 2019. The illness is not usually life threatening and is typically treated with antibiotics. Health officials have not yet definitively identified the source of the infections. But in Michigan — where more than 3,300 cases have been reported — officials say early information points to lettuce or salad greens as a possible culprit.