Texas’ health commissioner told lawmakers Monday they are still trying to determine the origin of a South Plains-Panhandle measles outbreak more than a month after the first patients reported symptoms.

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.

A Texas doctor warned people not to attend "measles parties" after the virus infected more than 100 West Texas residents over the past few weeks. Newsweek reached out to the Texas Department of State Health Services (DSHS) for comment via email.