Public health authorities said Tuesday that an outbreak of measles in western Texas has expanded, while a new case was confirmed nearby across state lines in New Mexico.

The Texas Department of State Health Services has identified 24 measles cases in connection with the onset of symptoms within the last two weeks. Gaines County, a small county in West Texas, has one of the highest rates of vaccine exemptions in the state.

In neighboring Lea County, New Mexico, residents were alerted Tuesday to the measles infection of an unvaccinated teenager, as well as the possible exposure of more people in Lovington at a hospital emergency room and sixth grade school gymnasium.