Taco Bell and its franchisees have been sued at least three times in federal court this week over the cyclosporiasis outbreak.

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

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