Warning Sign: River blindness parasite shows resistance

The worm that causes river blindness appears to be developing resistance to the sole drug that’s effective against it, a study in West Africa shows. The finding is bad news in the fight against this parasite, Onchocerca volvulus, which infects roughly 37 million people worldwide.

The river blindness parasite spreads among people bitten by certain black flies that live near fast-flowing water.