In 2000, the Centers for Disease Control and Prevention declared measles "eliminated" from the United States. But with measles continuing to spread and at times flourish in many parts of the globe, the U.S. has been unable to remain immune to the disease.
This year, the U.S. has its highest number of measles cases in 25 years. As of this week, the CDC has recorded 704 cases in 22 states.
The reemergence of measles is linked to parents who have chosen not to vaccinate their children against this highly contagious disease.