According to the society, the last US measles death was in 2015. A measles infection can have particularly devastating complications for pregnant women and young children, including pneumonia, neurological impairment, hearing loss and death.

CDC staff received an email this week telling them to avoid using more than a dozen terms or words-- including "health equity," "race," "bias," and "disparity" -- in their annual performance evaluations;

The outbreak is primarily affecting West Texas, but officials in San Antonio, New Braunfels and San Marcos are monitoring cases after an infected person recently visited the area, according to the Texas Department of State Health Services.