In a study published online in The Proceedings of the National Academy of Sciences, Dr. Charles Mackenzie and colleagues found that Ivermectin works, not by killing the worms directly, but by binding to proteins secreted by microfilariae that invade the host’s immune system. With the worm’s invasion tactic compromised, the host’s immune system is able to recover and fight off the parasite.
Mackenzie tells the NYT that Ivermectin “is an extraordinarily safe drug”. Since the killing process is slow, the worms are able to leave the eyes of individuals with severe cases of onchocerciasis. If the bodies of dead worms stay in the eyes, as caused by older drugs once used for treatment, it only worsens the blindness.