- A minute arthropod of the order Acarina, a vast assemblage of parasitic and (primarily) free-living organisms. Most are still undescribed, and only a relatively small number are of medical or veterinary importance as vectors or intermediate hosts of pathogenic agents, by directly causing dermatitis or tissue damage, or by causing blood or tissue fluid loss. The six-legged larvae of trombiculid mites, the chigger mites (Trombicula), are parasitic of humans and many mammals and birds, and are important as vectors of scrub typhus (tsutsugamushi disease) and other rickettsial agents. Some other important mites are Acarus hordei (barley m.), Demodex folliculorum (follicular or mange m.), Dermanyssus gallinae (red hen m.), Ornithonyssus bacoti (tropical rat m.), Ornithonyssus bursa (tropical fowl m.), Ornithonyssus sylviarum (northern fowl m.), Pyemotes tritici (straw or grain itch m.), and Sarcoptes scabiei (itch m.). [A.S.]
* * *mite 'mīt n any of numerous small to very minute arachnids of the order Acari that have a body without a constriction between the cephalothorax and abdomen, mandibles generally chelate or adapted for piercing, usu. four pairs of short legs in the adult and but three in the young larvae, and often breathing organs in the form of tracheae and that include parasites of insects and vertebrates some of which are important disease vectors, parasites of plants in which they frequently cause gall formation, pests of various stored products, and completely innocuous free-living aquatic and terrestrial forms see ITCH MITE
* * *n.a free-living or parasitic arthropod belonging to a group (Acarina) that also includes the tick. Most mites are small, averaging 1 mm or less in length. A mite has no antennae or wings, and its body is not divided into a distinct head, thorax, and abdomen. Medically important mites include the many species causing dermatitis (e.g. Dermatophagoides) and the harvest mite (see Trombicula), which transmits scrub typhus.
* * *(mīt) any arachnid arthropod of the order Acarina except the ticks. Most mites are minute and have transparent or semitransparent bodies; many are parasitic, causing skin irritation (acariasis). Families that have genera that attack humans include Acaridae, Cheyletiellidae, Demodicidae, Dermanyssidae, Glycyphagidae, Sarcoptidae, Tetranychidae, and Trombiculidae. Other genera that attack nonhuman mammals and birds are found in the families Halarachnidae, Listrophoridae, and Myobiidae.
Medical dictionary. 2011.