No See Um’s, Biting Midges
No see um’s/biting midges are a major nuisance along the Gulf Coast of the United States, Florida, South Carolina, Texas, Georgia, and North Carolina.
There are over 4,000 species of biting midges/no see um’s in the Ceratopogonidae family, and over 1,000 in just one genus, Culicoides. The distribution of midges in the genus Culicoides is world-wide; 47 species are known to occur in Florida. Species belonging to the genus Leptoconops occur in the tropics, sub-tropics, the Caribbean, and some coastal areas of southeast Florida.
Breeding areas can be very varied depending on the particular species. Areas with substantial salt marsh habitat are major producers of many biting midge species. Additional sources for some species, like the bluetongue virus vector Culicoides sonorensis Wirth and Jones, include highly organic soil that is wet but not underwater such as those found with high manure loads in swine, sheep and cattle farming operations.
In the U.S., the biting midges are primarily a nuisance and the major medical issue associated with Culicoides is allergic reactions to the bites. However, like other blood feeding Diptera, Culicoides species are vectors of pathogens that can cause disease in humans and animals. In Central and South America, western and central Africa, and some Caribbean islands, biting midges are the vectors of filarial worms in the genus Mansonella. These parasites cause infection in humans that produces dermatitis and skin lesions because the adult worms are located in the skin.
Biting midges, primarily the species Culicoides sonorensis, are responsible for transmission of bluetongue virus to sheep and cattle in the U.S. Bluetongue is a serious disease of ruminants. Bluetongue viruses are found world-wide and are transmitted by different Culicoides species in different regions. Many countries that are bluetongue free prohibit the movement of livestock from bluetongue endemic regions. The annual economic damage in lost trade is in the millions of dollars.
Other animal disease causing pathogens transmitted by the bite of infected biting midges include African Horse-sickness virus in equines that is confined primarily to Africa and Epizootic Hemorrhagic Disease virus in ruminants found in North America and principally having lethal effects on deer. Some equines experience allergic reactions to the bites, resulting in equine allergic dermatitis, affecting the withers, mane, tail and ears of the animal.