US Records Largest Cyclospora Outbreak as Investigators Hunt the Source
A record-breaking US outbreak of the parasite Cyclospora cayetanensis has infected 1,645 people since May, with over 5,100 more cases under investigation and more than 100 hospitalizations; Michigan reports the highest case count and suspects lettuce or salad greens. Health officials are coordinating state and federal labs to trace exposures and likely contaminated produce, while noting that oocysts shed in human feces require warm conditions to mature, which helps explain summer spikes. There is no vaccine; treatment is typically with trimethoprim–sulfamethoxazole. Investigations face challenges such as staffing shortages and the need to study sanitation practices on farms and potential asymptomatic carriers, as researchers try to pinpoint where the parasite entered the food supply.
