Eradicating disease was one of Jimmy Carter's great legacies

One of President Jimmy Carter's greatest legacies touches people's lives in highly remote parts of the world to this day. He targeted what are known as "neglected tropical diseases" - ones that upend people's lives, like river blindness and guinea worm. The World's Host Carolyn Beeler speaks with Kelly Callahan, who worked with Carter in various parts of Africa.