As the larval forms of
Onchocerca develop into adult worms at the site of the bite, they produce subcutaneous nodules
called onchocercomas, where numerous microfilariae are produced. They migrate into the skin, inducing a secondary
dermatitis, skin pigmentation changes, skin thickening, frank elephantiasis, and an often disabling itching. The
microfilariae also may migrate into the tissue of the eye and produce blindness due to severe uveal and corneal
inflammation.
