Michigan cyclosporiasis outbreak tops 6,100 cases, health officials say
The number of cyclosporiasis cases in Michigan continues to add up as the investigation continues into the origin of a parasite that can cause diarrhea and nausea several days after contaminated food was eaten.
The Michigan Department of Health and Human Services says there are 6,148 of cases as of July 20, up 1,146 from the 5,002 confirmed cases as of July 17.
As of July 16, 102 people had received hospital treatment for the ailment, more than double the 44 hospitalizations reported the previous week.
Michigan health officials report the case numbers on Mondays through Fridays. The hospital reports are updated once a week on Thursdays.
Impact in Michigan
The cyclosporiasis outbreak, which Michigan officials said could be the largest in U.S. history, came to the attention of state and local health officials in late June.
The outbreak was identified first by local officials in Monroe County and has since spread to 55 Michigan counties. Wayne County alone has reported more than 300 cases. Monroe, Washtenaw, Livingston, Oakland and Lenawee counties have each reported more than 100 cases.
Michigan typically sees around 50 cases of cyclosporiasis per year, according to MDHHS.
There are now 34 states investigating reports of the ailment.
What's causing the outbreak?
Michigan officials said July 13 that testing pointed to lettuce or salad greens as a potential source, though other foods hadn't been ruled out.
Efforts then focused on determining which supplier was involved
The Food and Drug Administration said on Sunday that a sample of lettuce from Taylor Farms that had tested positive for cyclospora was a false positive. That leaves the investigation officially still open.
Symptoms of the ailment
Cyclosporiasis is caused by the parasite Cyclospora cayetanensis and spreads when infected feces contaminate food or water.
Symptoms typically begin about a week after infection and include frequent watery diarrhea, loss of appetite, bloating, nausea and fatigue, lasting from two days to two weeks or longer.
The above video originally aired on July 16, 2026.
