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

The cyclosporiasis outbreak has sickened thousands of people nationwide, and Michigan has been the hardest hit.

State and federal investigators are probing the fast-food chain’s possible connection to cyclosporiasis

Nearly 7,000 cases of cyclosporiasis have been reported across the country

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