Mites are tiny members of the class Arachnida; less than 1 mm (0.04 in) in length, and have a simple, unsegmented body plan. Their small size makes them easily overlooked; some species live in water, many live in soil as decomposers, others live on plants, sometimes creating galls, while others again are predators or parasites. This last type includes the commercially important Varroa parasite of honey bees, as well as the scabies mite of humans. Most species are harmless to humans, but a few are associated with allergies or may transmit diseases.


Vector: Mite

Sarcoptes scabiei (Scabies Mite) or the itch mite is a parasitic mite (an arthropod) that burrows into skin and causes scabies. The mite is found in all parts of the world. Humans are not the only mammals that can become infected, wild and domesticated dogs and cats can be infected, in which it is one cause of mange.

The burrowing is carried out using the mouth parts and special cutting surfaces on the front legs. While these are being used, the mite anchors itself with suckers on its feet. Eggs are laid in small numbers as the mite burrows, and, as these hatch, six-legged larvae climb out on to the skin and search for hair follicles, where they feed and moult (discard old cuticles to grow). In the hair follicles, the larvae show the first nymphal stages, with eight legs.

Although the life-cycle is only about two weeks, individual patients are seldom found to have more than about a dozen mites on them. Even so, this number can cause agonising itching, especially at night, and severe damage to the skin often comes as a result of scratching, in particular by the introduction of infective bacteria, which may lead to impetigo or eczema.

Liponyssoides sanguineus (House-mouse Mite) is a species of mite that infests the house mouse. It can transmit human disease, is associated with causing rodent mite dermatitis in humans and is noted for carrying Rickettsia akari, which causes rickettsialpox.

Liponyssoides sanguineus has been collected from house mice and various rodent species in the USA, Eurasia, and Africa. Despite broad geographic distributions of the vector mite and the house mouse, confirmed reports of rickettsialpox are relatively sparse and sporadic.