San Antonio officials warn of measles exposure at UTSA and other locations after a visitor tested positive for the virus.

The largest measles outbreak in decades has reached San Antonio and San Marcos. Officials say an individual who tested positive for the virus in West Texas traveled to two major universities and one of the nation's busiest tourist attractions — the San Antonio River Walk.

There are growing concerns about Central Texans who were possibly exposed to measles. Most recently, someone who tested positive for the virus spent time at Texas State University in San Marcos, New Braunfels,