San Antonio is expected to be packed with visitors in March. With spring break crowds arriving next week comes a timely concern about measles after a potential exposure was reported in the Alamo City.

While a measles case has yet to be confirmed in San Antonio and Bexar County, hundreds of thousands of residents may have been exposed to the virus spreading rapidly throughout the state.

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.

The Legacy Traditional School in Cibolo has confirmed with KENS 5 that there is a measles case in a first-grade classroom.

The measles outbreak won't necessarily spread to North Texas, officials say, but communities with low vaccination rates are at risk.

A measles outbreak in Texas has reached San Antonio, with 90 cases reported, mostly in children. Vaccination remains crucial to control the spread.

Several San Antonio public schools have low measles vaccination rates that don't reach the recommended 95% threshold.

Officials at Legacy Traditional School – Cibolo said Thursday they had confirmed a measles case in a first-grade classroom. They later said the case was actually rubella.

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.