The number of confirmed measles cases in western Texas grew to 146, and it is possibly spreading to the central part of the state and neighboring New Mexico, health officials said Friday.

When the local hospital warned of a brewing measles outbreak, Kaleigh Brantner urged fellow residents of this rural West Texas community to beware of vaccinating their children. Two weeks later, her unvaccinated 7-year-old son came home from school with a fever.

Measles has been spreading across the U.S. for the last several weeks, sickening people in at least nine states amid a growing outbreak in western Texas. Several people have been hospitalized and at least one unvaccinated school-aged child in Texas has died,