A parasitic illness causing severe, "explosive" diarrhea is spreading fast across the US, with Michigan at the epicenter. The state has logged over 700 cases since June — compared to just 40–50 in a typical full year. At least 18 states are now monitoring clusters, and the CDC and FDA are working to trace the source, which remains unidentified.
A microscopic parasite called Cyclospora is triggering an unusual surge of intestinal illness across the United States, with Michigan bearing the brunt of the outbreak. The state has recorded more than 700 cases since June — a dramatic spike compared to the 40–50 cases it typically sees in an entire year. Cases are concentrated across seven counties in southeast Michigan, and at least 36 hospitalizations have been reported there alone.
Nationally, at least 18 states are monitoring clusters of cyclosporiasis, with New York, Illinois, and Texas also reporting elevated numbers. The CDC and FDA are actively investigating, but no single food source or multistate outbreak link has been confirmed. Past US outbreaks have been tied to fresh produce like basil, cilantro, raspberries, and bagged lettuce — items commonly consumed during the warmer May–August season when cases typically peak.
By the Numbers:
Why it matters: Cyclosporiasis is rarely life-threatening for healthy individuals, but this outbreak's scale is straining already underfunded public health departments. Immunocompromised patients face higher risks of prolonged illness, and the unidentified source makes prevention difficult — underscoring the importance of robust public health infrastructure.
