United States health authorities have traced a multistate outbreak of cyclosporiasis, a foodborne parasitic illness that causes severe diarrhoea, to shredded iceberg lettuce served at selected Taco Bell restaurants.
The finding follows an investigation by the US Food and Drug Administration and the Centers for Disease Control and Prevention, which traced the contamination to a single supplier of iceberg lettuce from Mexico used at Taco Bell outlets in five states.
According to the CDC, 1,644 people in Indiana, Kentucky, Michigan, Ohio and West Virginia have been confirmed to be infected with cyclosporiasis linked to the outbreak.
The illness has resulted in 94 hospitalisations, although no deaths have been recorded.
Health officials said the confirmed cases relate specifically to the Taco Bell outbreak and do not include infections caused by other contaminated foods.
Cyclosporiasis is caused by the parasite Cyclospora cayetanensis and commonly leads to severe diarrhoea, stomach cramps, nausea, fatigue and dehydration. Without treatment, symptoms can last for more than a month.
Federal authorities have advised consumers in the affected states not to eat shredded iceberg lettuce served at Taco Bell while the investigation continues.
In response, Taco Bell said it had voluntarily removed the potentially affected lettuce from selected restaurants and permanently discontinued the ingredient from the supplier nationwide.
The company said replacement supplies were delivered within 24 hours in affected locations, adding that protecting public health remained a shared responsibility between restaurants, suppliers and government agencies.
Health experts say previous outbreaks of cyclosporiasis have been linked to fresh produce, including bagged salads, basil, cilantro, raspberries, snow peas and scallions.
Officials also recommend thoroughly washing fresh produce and cooking vegetables where possible, noting that temperatures above 70°C effectively kill the parasite.
Michigan has recorded one of the highest numbers of infections this year, with state authorities reporting more than 5,000 probable and confirmed cases.
The FDA said differences between state and national figures are common because surveillance systems are updated at different times and often use different reporting methods.
