A parasitic infection causing explosive, relentless diarrhea has reached an unprecedented scale across the Midwest and several other U.S. states, and thousands of patients may be going undiagnosed because most standard laboratory stool tests cannot detect it.
Ohio has confirmed 177 cases of cyclosporiasis in 2026 — 171 of which appeared in less than two weeks, mostly since June 20, across 43 of the state's 88 counties, according to Ohio Department of Health Director Dr. Bruce Vanderhoff. Michigan has confirmed 708 cases as of July 7, 2026 — approximately 14 times higher than the state's annual average — concentrated in Southeast Michigan counties including Wayne, Monroe, Oakland, and Washtenaw. Nationally, the infection has been reported in Michigan, Ohio, Illinois, Indiana, New York, North Carolina, Texas, and other states.
