Simulium SPP., Vectors of Onchocerca Volvulus: Life Cycle and Control

Members of the dipteran genus Simulium are of significant medical and veterinary importance. They belong to the suborder Nematocera and family Simuliidae, usually called black flies. These flies have long segmented antennae of about 11 segments, and all immature stages are aquatic, or at least live in very moist environments. Members of the family have a reduced mesothoracic segment giving them the appearance of having a humped back hence their alternate name humped back flies. Some members are also called buffalo gnats. Most of the species belong to the genera Cnephia, Simulium, and Prosimulium.

Simulium damnosum (the most widely known), and S. neavei vector the filarial parasite Onchocerca volvulus that causes human onchocerciasis (‘oncho’) or river blindness in several East and West African countries. S. ochraceum, a smaller species, is the most common vector of the parasite in Mexico and several Central and South American countries. Other species of Simulium, and those of Cnephia...