Guinea worm was eradicated largely through efforts of former president Carter. It is endemic in areas where very poor people don't have access to high tech solutions and often no electricity. A simple filter removes the worm, which causes painful disease and blindness, from water. The Carter center made it available to all families. And the worm didn't go away but isn't infecting people.
When Carter went on a visit, locals hung up a banner "look out worms! Here comes Jimmy!"