US health authorities are investigating a multistate outbreak of cyclosporiasis, a foodborne illness caused by the microscopic parasite Cyclospora cayetanensis. The outbreak has spread across more than 30 states, with Michigan recording the highest number of cases. Investigators are working to identify the exact source, though fresh lettuce and other leafy greens are among the leading suspects.
According to the US Centers for Disease Control and Prevention (CDC), more than 1,600 confirmed cases have been reported since May 1, while thousands of additional suspected infections are still being reviewed. Officials caution that the actual number of illnesses could be much higher because it often takes several weeks for cases to be diagnosed and reported.
The investigation has also focused on Taco Bell after several infected people said they had recently eaten at the restaurant. However, health officials stress that many patients had no connection to the fast-food chain, indicating it is not the only possible source. As a precaution, some Taco Bell outlets in Michigan have temporarily stopped serving fresh ingredients, including lettuce, onions, cilantro, pico de gallo and guacamole, while suppliers are being traced.
Cyclospora is a parasite that spreads through food or water contaminated with human waste. Unlike many common stomach infections, symptoms usually appear about a week after consuming contaminated food. People infected may suffer prolonged watery diarrhoea, stomach cramps, nausea, fatigue, loss of appetite and weight loss. Without treatment, the illness can last for weeks or even longer, disrupting work, travel and daily life. Doctors say the infection can usually be treated successfully with prescribed antibiotics.
