Cyclosporiasis Outbreak Surges Across US, Hitting Michigan Hardest

Health officials are investigating a significant surge in cyclosporiasis, a parasitic intestinal illness causing watery and sometimes "explosive" diarrhea, across the United States. The outbreak, which began appearing in May, has affected at least 17 states, with Michigan reporting the highest caseload—surging from its annual average of roughly 50 to nearly 1,000 confirmed infections. Ohio, North Carolina, Illinois, and Texas have also reported notable clusters. While the CDC’s latest national data lags behind state reports, health experts warn the true number of cases is likely higher due to underreporting and testing delays. No specific source has yet been identified, though previous outbreaks have been linked to fresh produce such as basil, cilantro, raspberries, and leafy greens.

The parasite, *Cyclospora cayetanensis*, spreads through feces-contaminated water or food and thrives in warm conditions, leading some experts to suggest climate change may be increasing its prevalence. Symptoms can persist for weeks, though the illness is rarely fatal. In response to the surge, some businesses, including certain Taco Bell locations, have temporarily removed high-risk ingredients like lettuce and cilantro from their menus. Health authorities advise consumers to thoroughly wash fresh produce, consider cooking vegetables, and opt for whole heads of lettuce rather than pre-packaged mixes while investigations into the contamination source continue.