Guinea worm, river blindness and elephantiasis are among the world's neglected tropical diseases. A battle is on to wipe them out

One infection known as dracunculiasis can cause people to suffer a burning blister that bursts as a parasite called the Guinea worm breaks through the skin.

Another one, elephantiasis, causes grotesque swelling in limbs. Yet another, known as river blindness, occurs when the larvae of parasitic...