Desc: 37 Million and Counting: Directed by Aaron Edell. African river blindness is a disease caused by a parasitic worm that is transmitted through the bite of a blackfly. The worms swim under the skin causing an extremely severe skin irritation. Eventually, the worms swim into the eye and scar the retina leading to blindness. Merck & Co. offers a drug that kills the worms and completely treats the symptoms for free, yet 37 million people are still infected.