The Centers for Disease Control and Prevention said Tuesday that it has confirmed 1,645 cases of cyclosporiasis acquired in the U.S. since May 1.
Among the cases of the gastrointestinal disease confirmed by federal health officials, 141 patients needed hospitalization, with no deaths. The median onset date for the illness among the cases is June 22, the CDC said.
The agency said several states reported having more cyclosporiasis cases than the same timeframe in 2025 and that state health officials reported a higher number of cases overall.
The CDC is working with state agencies to analyze another 5,100 cases to confirm whether those patients suffered from domestically contracted cyclosporiasis.
Cases have been confirmed in Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Nebraska, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, Tennessee, Texas, Utah, Virginia, Washington, West Virginia and Wisconsin.
In addition, 440 cases were confirmed by the CDC where the patient traveled outside the country in the two weeks prior to getting sick.
Federal officials have not identified the exact source of the cyclosporiasis cases or the cyclospora parasite that causes the disease. The parasite infects people within two days to two weeks after they consume contaminated food or water.
Common symptoms include watery diarrhea, bloating, cramping, fatigue, increased gas, loss of appetite, nausea and weight loss. Uncommon symptoms include body aches, headache, low-grade fever, vomiting and other flu-like symptoms, the CDC says on its website.
The Michigan Department of Health and Human Services said Monday that lettuce or other leafy greens are a “potential source for this outbreak.” Michigan has the largest number of cases confirmed by the CDC, between 500 and 901, and state health officials are reporting 2,640 cases.
Michigan health officials recommend people buy whole heads of lettuce instead of prepackaged bags, throw out the outer layers when preparing lettuce, wash the inner leaves and cook any greens to a temperature of at least 158 degrees, which kills cyclospora.
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