Experts Urge Produce Safety as Cyclospora Illnesses Rise.
At least 34 U.S. states are experiencing a surge in Cyclospora infections, with 1,645 confirmed cases reported since May 1, 2026. A specific multistate cluster of over 400 cases is heavily concentrated in the Midwest and Appalachia, primarily affecting Michigan, Ohio, West Virginia, and Kentucky.
Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora. Health officials and food safety experts are encouraging residents to take extra precautions while the source of the outbreak remains under investigation.
The illness is commonly linked to contaminated food or water and often appears during the spring and summer months.
“When this issue became more prevalent throughout the state, we immediately started looking at how Extension can best share information quickly among our staff members and with community members,” said David Civittolo, associate dean and director of Extension.
Cyclospora infection can cause frequent watery diarrhea that may last for weeks. Other symptoms include stomach cramps, nausea, fatigue, bloating, loss of appetite, and weight loss. Because symptoms may not appear until one or two weeks after exposure, identifying the source of an outbreak can be difficult.
“It is typical to see cyclosporiasis cases surge in the spring and summer months,” said Nicole Arnold, assistant professor and food safety field specialist with Ohio State Extension.
Food safety specialists explain that Cyclospora becomes infectious after spending time in the environment, often in contaminated water or soil. Fresh fruits, vegetables, and herbs can become contaminated before reaching consumers. Previous outbreaks have been associated with leafy greens, basil, cilantro, berries, peas, and green onions.
Experts recommend that consumers continue washing fresh produce under clean running water before eating it. While washing may help reduce contamination, it cannot completely eliminate the parasite. Cooking produce and herbs, when possible, can provide additional protection because Cyclospora is destroyed at high temperatures.
People who experience symptoms should seek medical attention and request testing. Early diagnosis can help health officials better understand and track the outbreak. The illness can be treated with appropriate antibiotics when prescribed by healthcare professionals.
Consumers are also encouraged to be cautious when eating away from home because restaurants may serve raw vegetables and fresh herbs. Additional precautions may be especially important for young children, older adults, and individuals with weakened immune systems.