An outbreak of measles has struck the South Plains region of Texas, with 90 cases reported since late January, according to the Texas Department of State Health Services (DSHS). The outbreak has affected seven counties in total,

The Hays County Health Department has issued an alert of a potential measles exposure in San Marcos. The San Antonio Metropolitan Health District has issued an alert of a potential measles exposure there.

Texas' measles outbreak is now at 90 cases, the highest yearly case count since 1992. Experts say the number is likely to grow more. Here's why.