A child’s death this past week in Texas is the first U.S. death from measles, a highly contagious but preventable respiratory disease since 2015, according to the U.S. Centers for Disease

The number of people with measles in Texas increased to 146 in an outbreak that led this week to the death of an unvaccinated school-aged child, health officials said Friday. The number of cases — Texas’ largest in nearly 30 years — increased by 22 since Tuesday.

As the measles outbreak in West Texas continues to grow, North Texas doctors say they’re fielding a growing number of questions from concerned parents. Dr. Christopher Dreiling, a pediatrician at Pediatric Associates of Dallas, said his office has had “dozens and dozens” of measles inquiries.