CDC reports larger-than-usual Cyclospora outbreak across multiple states

The Centers for Disease Control and Prevention has identified 1,645 confirmed domestic Cyclospora cases since May 1, along with more than 5,100 additional cases still needing analysis, in a 2026 outbreak larger than usual. Of the patients with available information, 141 were hospitalized and none died. CDC identified a multistate outbreak in Michigan, Ohio, West Virginia and Kentucky, where symptoms began on or after June 22.

Cyclospora cayetanensis is a microscopic parasite that causes cyclosporiasis, an intestinal illness most often marked by watery diarrhea. Symptoms usually begin about one week after exposure, but they can appear as soon as 2 days later or as late as 2 weeks or more. The illness can be acquired through contaminated food or water, including while traveling outside the United States, and federal, state and regulatory officials monitor cyclosporiasis year-round to detect outbreaks tied to a common food source.

Tracking the source has been difficult. Laboratory tests can miss Cyclospora even when patients have symptoms, and the parasite is not always included in routine stool testing. The long incubation period also makes it harder for sick people to remember what they ate before getting sick. The true number of illnesses is likely higher than reported because some people recover without medical care and are never tested.

CDC and the Food and Drug Administration are investigating several outbreaks, but no single food source has been confirmed in the current outbreak. Cyclosporiasis outbreaks have been associated with fresh fruits and vegetables around the world, including in the United States, and infected people can shed the parasite in feces, which can contaminate food, water and the environment if hygiene is poor. U.S. foodborne outbreaks have been reported since the mid-1990s and have been linked to imported raspberries, basil, snow peas, mesclun lettuce and cilantro. No commercially frozen produce has been implicated to date.

Washing hands and fresh produce thoroughly under running water, following safe food-handling practices and avoiding food or water that may be contaminated with feces can reduce risk. Cooking kills the parasite, and heating food to 176 degrees Fahrenheit, or 80 degrees Celsius, or higher is effective. FDA formed a Cyclospora Task Force in 2019 and released a prevention, response and research action plan for produce in 2021.