STORYLINE · active
Over 900 residents in Washtenaw County, Michigan, have been diagnosed with cyclosporiasis since mid-June, prompting intensive interviews and receipt/food app analysis by public health nurses.
More than 900 people in Washtenaw County, Michigan, have been sickened with cyclosporiasis since mid-June, and public health nurse Linda Kim has been conducting detailed interviews with patients to trace the source of the outbreak. Kim, a nurse at the county health department, has spoken to more than 100 of the sickened individuals, many of whom describe the illness as one of the worst they have experienced.
Monroe County, Michigan, has recorded 286 cyclosporiasis cases, making it one of the hardest-hit areas in the largest Cyclospora outbreak in U.S. history, which has reached 4,173 confirmed cases across 41 states. Residents describe weeks of diarrhea, severe cramping and frequent trips to the bathroom, while authorities have not identified the contaminated food driving the outbreak.
The U.S. Centers for Disease Control and Prevention reported more than 4,100 confirmed cases of cyclosporiasis across 41 states on Wednesday, more than double the total from a week earlier, including 308 hospitalizations and no deaths.
The U.S. Centers for Disease Control and Prevention downgraded active surveillance for Cyclospora cayetanensis to optional in July 2025, a decision that left public health authorities unable to detect the scale of a fast-growing parasitic outbreak until weeks after contaminated food had likely reached consumers, according to Dr. Robert B. Shpiner, a clinical professor of medicine at the David Geffen School of Medicine at UCLA, who detailed the timeline in a commentary published Thursday in The Guardian. As of July 15, the CDC had confirmed 1,645 domestically acquired cases across 34 states with 141 hospitalizations, and was tracking more than 5,100 additional suspected cases.