More than 250 species of mites are recognized as the cause of health-related problems for humans and domestic animals. Types of problems include: (1) temporary irritation of the skin due to bites or feeding on host skin, fur, and feathers; (2) persistent dermatitis in response to mites that invade the skin or hair follicles; (3) mite-induced allergies; (4) transmission of pathogenic microbial agents and metazoan parasites; (5) intermediate hosting of parasites, notably tapeworms; (6) invasion of respiratory passages, ear canals, and occasionally internal organs; (7) an abnormal fear of mites, or “acarophobia;” and (8) delusory acariosis , a psychological condition in which individuals are convinced that they are being attacked by mites when, in fact, no mites are involved. The general term for infestations of animals by mites is called “acarinism,” whereas any disease condition caused by mites is called “acariasis.” Mites comprise the arachnid subclass “ Acari ,” which is divided into two major groups: the Antactinotrichida and Actinotrichida . These are further subdivided into seven orders. The body is divided into two major regions: the anterior gnathosoma , bearing the pedipalps and chelicerae; and the idiosoma , the remainder of the body, bearing the legs and eyes. The basic developmental stages in the life history of mites are the egg, prelarva, larva, protonymph, deutonymph, tritonymph, and adult. Mites can adversely affect human health in many ways. They can infest homes including carpets, mattresses and bedding, clothing, stored food products, and household pets. The most widely recognized mite problems that affect human health are respiratory allergies caused by mites, infesting house dust.