Onchocerciasis is a disease of
public health importance. It is estimated that about 18 million people
world-wide are infected with the disease whereas 270,000 people have become
blind as a result of the disease (WHO, 2003; Okulicz, 2005).
The disease is caused by a
parasitic nematode spread to man by the bites of several species of black flies
of the genus Simulium. Black flies breed in fast flowing rivers and streams. In
most rural communities in Africa, the local folks depend on land as their major
source of livelihood farming, hunting, logging, honey-gathering, etc. These
activities bring humans in contact with and expose them to the ravaging bites
of forest insects, especially black flies.