NEW YORK, United States (AFP) — United States (US) officials on Friday pinned the source of a diarrhoea-causing foodborne parasite as shredded iceberg lettuce used by the fast food chain Taco Bell.

A federal investigation by the Food and Drug Administration traced the contamination back to a single supplier of iceberg lettuce from Mexico, which was used by Taco Bell locations in five states, according to a statement from the Centres for Disease Control.

The CDC said that more than 1,644 people in five states — Indiana, Kentucky, Michigan, Ohio and West Virginia — were confirmed to be infected with cyclosporiasis, which can cause “explosive diarrhoea,” among other symptoms.