Health officials are investigating a "fast-moving" E. coli outbreak in Michigan and Ohio, the CDC says

Public health officials are investigating a growing number of illnesses linked to E. coli bacteria in Michigan and Ohio, the Centers for Disease Control and Prevention said this week. At least 29 cases have been reported so far, and CDC says the number is expected to increase.

The CDC says it has not yet identified the food that is causing the "fast-moving outbreak." It urged anyone with symptoms of an E. coli infection to report them to their local health departments. Fever, diarrhea, vomiting, dizziness, and dehydration are some signs of the infection.

The onset of symptoms typically happens three or four days after a person ingests the bacteria, and most people who get sick will recover without treatment within seven days, the CDC said.