Health officials say there are now 10 reported cases of measles in Missouri, including three students.

The Kansas City Star reports that the Kansas City Health Department plans to announce seven more exposure sites in the Kansas City area.

Department spokesman Bill Snook says the three students with the virus attend Liberty Public Schools. Two students pose no risk, but a third student may have exposed others at South Valley Middle School.

A district spokesman says children who aren’t immunized are being held out of school.

Missouri Department of Health and Senior Service official Kerri Tesreau says the cases may have come from an international traveler living in Missouri.

Health officials in Wisconsin, Minnesota and Iowa are warning that a Missouri traveler may have exposed their residents to the virus.

Christopher Furlong, Getty Images