Mystery Cyclospora Outbreak in US: Over 400 Sick as CDC Investigates

The U.S. Centers for Disease Control and Prevention (CDC), in collaboration with state and federal health agencies, is investigating several outbreaks of cyclosporiasis. A major outbreak has been reported in at least four Midwestern states: Michigan, Ohio, West Virginia, and Kentucky. Public health officials are interviewing affected individuals to determine what foods they consumed before symptoms began, but the source has not yet been confirmed.

Cases have been rising since early May. In addition to the large multistate outbreak, other clusters are being investigated across the country. As of July 13, more than 400 people infected with Cyclospora have been reported to the CDC in connection with the outbreak, with illnesses starting on or after June 22, 2026. Health officials believe the true number of illnesses is likely higher, as some people recover without seeking medical care and are not tested.

Cyclosporiasis is generally not life-threatening, but it can cause severe symptoms requiring hospitalization. Symptoms typically appear about one week after infection (ranging from 2 days to 2 weeks or more). Without treatment, they can persist for days, weeks, or even longer.

The CDC and the Food and Drug Administration (FDA) are collecting data to identify the contaminated food source. Investigators gather information on patients' age, race, ethnicity, and other demographics, as well as the foods they ate before becoming ill. This data may reveal patterns that help trace the source.

Individuals experiencing symptoms should contact their healthcare provider promptly. Those diagnosed with cyclosporiasis may be contacted by health officials to provide details about their food consumption. To reduce risk, consumers are advised to stay informed about food recalls and follow prevention guidelines.