New York (AFP) - US officials on Friday pinned the source of a diarrhea-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 Centers for Disease and 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 diarrhea,” among other symptoms.

There have been no deaths and 94 hospitalizations related to that outbreak, the health agency said.

The CDC said that those illnesses were lab-confirmed and linked specifically to the outbreak at Taco Bell locations in those states.

The figure does not encompass all cyclosporiasis infections arising from other causes.

The CDC did not name the supplier, but Taylor Farms – which has production facilities across the US, and in Canada and Mexico – said Friday it had sold the lettuce to Taco Bell.

The company said it was “voluntarily removing all iceberg lettuce sourced from central Mexico.”

“While the FDA traceback is indicating a specific independent farm, which represents less than one percent of the US’s iceberg lettuce supply, as the potential source of the outbreak, we have removed all iceberg lettuce from the region indefinitely,” it said in a statement.

The company said none of its branded salads or kits were associated with the outbreak, nor did any of its kits contain iceberg lettuce.

- Cooking reduces risk -

In its own statement, Taco Bell said it also had voluntarily removed “potentially impacted lettuce from a supplier in select states.”

“The affected ingredient from our supplier is being indefinitely removed from our supply chain nationwide and will be replaced within 24 hours in select states,” the company added.

Federal officials warned against eating shredded iceberg lettuce from Taco Bell in the five states mentioned.

Untreated, cyclosporiasis could last more than a month. It is generally not life-threatening, but can cause dehydration.

In the past, foods including bagged salad mixes, fresh cilantro, fresh basil, raspberries, snow peas and scallions have been linked to cyclosporiasis.

Officials across the country recommend thoroughly washing produce or, even better, cooking it, as heat higher than 158F (70C) kills the parasite.

Michigan has been particularly hard hit this year by cyclosporiasis, and authorities there have reported more than 5,000 cases.

The FDA cautioned that individual state data often differs from national surveillance numbers as states often include both probable and confirmed cases. There is also a lag between reporting and updating national data.