Taco Bell in Canada says the lettuce that has caused an outbreak of the diarrhea-causing parasite cyclospora in the United States has not been served at its locations.

Michigan, which is where much of the outbreak is centered, has reported over 4,300 cases of cyclosporiasis, which can cause diarrhea and a low grade fever.

The locations were in Indiana, Kentucky, Michigan, Ohio and West Virginia

Upwards of 1,600 people who contracted cyclosporiasis reported eating at the chain beforehand, the CDC and FDA said.