A growing measles outbreak in Columbus, Ohio, has sickened more than a dozen unvaccinated children and hospitalized nine of them, and local public health officials are seeking assistance from the US Centers for Disease Control and Prevention.The CDC confirmed Thursday that it is aware of the cases and is “deploying a small team to Ohio to assist on the ground with the investigation.” “State and local health authorities are in the process of notifying potentially exposed residents, making sure they are vaccinated, and helping any community members who may have been exposed understand the signs and symptoms of measles infection,” CDC spokesperson Kristen Nordlund said in an email to CNN.“Anyone who may have been exposed should follow up with their healthcare provider.” When the measles outbreak was first reported last week, only four confirmed cases had been identified in one child-care facility, which temporarily closed – but the number of cases and facilities involved has grown.Health officials with Columbus Public Health and Franklin County Public Health have been investigating these cases and tracing any contacts who may have been exposed to the measles virus.Officials at Columbus Public Health are encouraging parents to make sure their children are up to date on their immunizations, including the measles, mumps and rubella vaccine, known as the MMR vaccine."