Many Texas doctors said they fear the current measles outbreak may be just the beginning, given how state data shows an increasing number of parents are opting out of vaccinating their children.As of Tuesday night,

Measles is caused by a highly contagious virus that's airborne and spreads easily when an infected person breathes, sneezes or coughs. It is preventable through vaccines, and has been considered eliminated from the U.S. since 2000.