Health officials across the United States are currently monitoring a significant rise in cyclosporiasis, a gastrointestinal illness caused by the microscopic parasite Cyclospora cayetanensis. As of early July 2026, the Centers for Disease Control and Prevention (CDC) is tracking confirmed cases across at least 31 states. While the CDC has reported 843 confirmed cases of domestically acquired foodborne infection since May 1, officials are also investigating more than 1,500 additional cases that are pending analysis. Furthermore, 343 cases have been identified as being acquired during international travel. Nationwide, 86 people have been hospitalized due to the illness, though no deaths have been reported.
The Scope of the Outbreak
The impact of the current outbreak varies significantly by region. Michigan has experienced the highest volume of illness, with the state health department reporting 2,640 cases across 43 counties and 44 hospitalizations as of July 13. Other states are also seeing elevated numbers; Ohio has reported 364 cases, New York has reported 470, New Jersey has reported 33, and Connecticut has reported 23. In contrast, some regions report more stable trends. The Minnesota Department of Health stated that its current case numbers are consistent with typical expectations for this time of year and that no specific outbreaks have been identified within the state. Public health investigators are working to determine the source of the infections. While no specific grower, supplier, or produce item has been definitively identified, officials are focusing their investigation on fresh produce, specifically lettuce and other salad greens. The FDA’s Coordinated Outbreak Response and Evaluation (CORE) network is currently conducting traceback investigations on various items, including white and green onions, cucumbers, and cilantro. Previous investigations by the CDC have identified potential clusters linked to grocery chains, catered events, and Mexican-style restaurants.
Understanding the Parasite and Symptoms
Cyclospora cayetanensis is a parasite that does not spread easily from person to person; rather, it is typically transmitted by consuming food or water contaminated with feces. Recreational water exposure, such as swimming in lakes, is not considered a recognized risk factor. The primary symptom of cyclosporiasis is frequent, watery, and sometimes “explosive” diarrhea. Other symptoms include: * Nausea and vomiting * Stomach cramps and bloating * Loss of appetite and fatigue * Low-grade fever * Weight loss Symptoms can persist for weeks if left untreated and may occasionally lapse before returning. Because the parasite is not culturable like bacteria or viruses, diagnosis requires direct microscopic evidence from stool samples. Health officials advise anyone experiencing persistent, watery diarrhea lasting more than a few days to consult a healthcare provider and specifically request testing for Cyclospora. The illness is treated with antibiotics, and maintaining hydration is vital to recovery.
For more on this story, see 6 confirmed cases of cyclosporiasis found in Ionia County as statewide numbers jump to 700.
Challenges in Surveillance and Investigation
Tracking this parasite presents unique challenges to public health agencies. While states may still conduct their own surveillance, experts have warned that such cuts could hinder the ability to identify rising illness trends and complicate outbreak responses. Furthermore, traceback investigations are inherently complex. Because the parasite has a long incubation period—ranging from two days to two weeks—and food distribution networks are highly intricate, identifying a single source of contamination can be difficult. In many previous outbreaks, including those in 2022 and 2024, investigations into the food source remained inconclusive.
Reducing Risk of Infection
State and federal health departments emphasize that while washing produce does not guarantee safety, it can help reduce the risk of infection. Recommended safety measures include: * Avoid pre-packaged items: MDHHS recommends avoiding bagged lettuce and salad greens, opting instead for whole heads of lettuce. * Proper preparation: Discard the outer layers of leafy greens and wash inner leaves thoroughly under clean, running water. * Scrubbing produce: Use a clean produce brush to scrub firm fruits and vegetables, such as melons and cucumbers. * Cooking: Cooking produce to a temperature of at least 158 degrees is the most effective way to kill the parasite. * Hygiene: Wash hands with soap and water before and after preparing raw fruits and vegetables. * Storage: Refrigerate cut, peeled, or cooked produce within two hours. These precautions are particularly important for individuals at higher risk of severe dehydration, including infants, young children, older adults, and those with weakened immune systems, such as organ transplant recipients or those undergoing chemotherapy.
