A Texas measles outbreak has doubled in the last week to 124 cases, state health officials said Tuesday, a day after they warned a person infected with the highly contagious disease had traveled from the outbreak zone.

Confirmed measles cases in Texas have reached at least 90, making this the worst measles outbreak in 30 years. Experts warn the number of Texas cases is likely much higher.

Officials in Central Texas are warning the public about a possible spread of measles as they say a person who visited the area had tested positive for the disease. The Hays County Health Department claimed Sunday that the patient is an individual who was in San Marcos—about 30 miles southwest of Austin—and spent time at a local college and restaurant between 3 p.