Olathe ? The Johnson County Health Department is investigating the county’s first measles case in nearly six years.

A department official says the person, who became ill earlier this month, was not vaccinated against measles.

Blue Valley North High School sent an e-mail Wednesday to parents reporting that measles was found at that school. A small number of students and staff who hadn’t been vaccinated were told to stay home until May 9.

The department got confirmation of the case late Tuesday. About 10 people who had contact with the patient had not been vaccinated. But the health department says getting a shot now will not prevent them from becoming ill or infecting others.

The Kansas City Star reports that the most recent measles case in Johnson County was in May 2006.