A bacterial illness is plaguing day-care centers in central Ohio, and health officials warn it could spread if parents aren’t vigilant.

The Columbus Dispatch reports Wednesday that the number of reported cases of shigella more than doubled in September in Franklin County, which includes Columbus. There have been 435 cases, compared with reported numbers in the teens the past two years.

The disease causes diarrhea and is easily spread if care isn’t taken when changing diapers, preparing food and cleaning up after bathroom breaks.

Dr. Mysheika Roberts, Columbus Public Health’s medical director, says there have been confirmed cases of shigella at 30 day-care centers in the city this year.