There are almost 5800 species of biting midges in about 125 genera, but only fourgenera have species feeding on vertebrates. Medically the most important twogenera are Leptoconops, which is mainly found in the tropicsand subtropics, including the Caribbean area and parts of the USA, andCulicoides, which has an almost worldwide distribution. Inmany parts of the world species of Culicoides, and in theAmericas also Leptoconops, can constitute serious bitingproblems. Culicoides species are vectors of filarial worms,such as Mansonella perstans and Mansonellastreptocerca in Africa, while Culicoides furens isa vector of Mansonella ozzardi in the Americas. All theseparasites are usually regarded as non-pathogenic to humans. Although manyLeptoconops species are biting pests they are not usuallyimportant disease vectors.

The only virus transmitted to humans by biting midges is Oropouche virus in theAmericas.

Adults are sometimes known as midges or biting midges, and, especially in theAmericas, as ‘no-see-ums’. In Australia and some other countries they are oftencalled sand flies, but this name is unfortunate and should be avoided becausephlebotomines (Chapter 5) and occasionally simuliids (Chapter 4) may also bereferred to as sand flies. The most appropriate common name is biting midges;this terminology serves to distinguish them from other small non-biting flieswhich are often referred to as midges.