Taco Bell has removed several fresh ingredients, such as lettuce, from its menus at locations across the country, including in Texas and Michigan.

The menu changes come as health officials investigate a cyclosporiasis outbreak

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

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