Some private schools have shut down because of a rapidly escalating measles outbreak in West Texas. Local health departments are overstretched, pausing other important work as they race to limit the spread of this highly contagious virus. Since the outbreak emerged three weeks ago, the Texas health department has confirmed 90 cases with 16 hospitalizations, as of Feb. 21. Most of those infected are under age 18. Officials suspect that nine additional measles cases reported in New Mexico, across the border from the epicenter of the Texas outbreak in Gaines County, are linked to the Texas outbreak.