Ten more cases of mumps have been diagnosed in Douglas County, authorities said this afternoon, bringing the total to 21 since last week.

“It’s a concern, definitely,” said Sheryl Tirol-Goodwin, a spokeswoman for the Douglas County Health Department. “It’s been a concern since Friday.”

Most of the cases are in people between ages 19 and 26, she said. Seven of the first 11 cases were in Kansas University students, but Tirol-Goodwin didn’t have the breakdown for the latest cases.

Mumps is a viral infection of the salivary glands that is passed through saliva and causes swelling in the jaw, as well as headaches and fever. Health officials recommend frequent hand-washing and other hygienic measures to prevent its spread.