The CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration are investigating a multistate outbreak of Cyclospora infections linked to a bagged salad mix containing iceberg lettuce, carrots, and red cabbage produced by Fresh Express.

The outbreak has also expanded to iceberg lettuce sold at Walmart, the Food and Drug Administration says.

The Walmart salad recall is for Marketside Classic Iceberg Salad, sold in 12- and 24-ounce bags in stores in Iowa, Minnesota, Michigan, Nebraska, North Dakota, South Dakota and Wisconsin.

The CDC and the FDA made an additional announcement on June 19 warning consumers to avoid eating bagged garden salads from the following store brands: ALDI, Hy-Vee, and Jewel-Osco.

A multistate investigation is underway for the outbreak, which is primarily spread by eating food (or drinking water) that has been contaminated with feces that contain the parasite.