Various species of Acari, including:
Human itch mite (Sarcoptes scabiei hominis)
Pest description and damage Mites that may affect humans directly can be divided into four general groups: those that 1) parasitize humans; 2) normally parasitize birds, or mammals other than humans, but occasionally may bite humans; 3) infest human food; and 4) feed on plants and occasionally become pests when they enter homes in large numbers.
The most important mite parasitizing people is the human itch mite, Sarcoptes scabiei hominis, which causes scabies. Human itch mites cause itching that is most intense when the mites are stimulated by warmth; for example, when the person is in bed. They tunnel just under the skin and appear as reddened streaks. Scabies can be confused with other conditions, so suspected cases should be confirmed by a physician. Confirmed cases require medical treatment. The mites are transmitted by direct personal contact and through bedding, clothing, etc. Clothing can be disinfected by hot laundering or dry-cleaning.
Mites that normally parasitize rodents or birds occasionally may invade homes. Such invasions are most likely when the mites' normal hosts have been removed; for example, during rodent control efforts. Tropical rat mite bites are irritating and occasionally cause painful dermatitis. Northern fowl mites and chicken mites will bite humans and cause itching. Mouse mites will bite and can transmit diseases. Any of these mites is controlled best by identifying the source and removing it. This may involve trapping rodents and destroying bird nests. Concurrent use of insecticides may be necessary in the case of heavy infestations.
Flour mites, fruit mites, sugar mites, house mites and cheese mites infest food and can also cause grocer's itch and other dermatitis symptoms. They are controlled best by identifying and destroying the source. Straw itch mites may cause conditions that have been called grain itch, straw itch, mattress itch, and hay itch. Straw itch mites normally are beneficial because they prey on stored grain pests, but when they run out of normal food, they attack humans and cause a very itchy bite.
Clover mites and house mites do not attack humans, but they occasionally enter homes in large numbers. Clover mites often move from outdoor lawns into homes in the fall. A 6 to 24 inch grass-free band all around the house may prevent such invasions. Once they have entered, a vacuum cleaner is effective in reducing their numbers. Avoid crushing clover mites, because that may stain fabrics. House-dust mites occur in homes and occasionally cause allergic reactions. Their detection and identification require special equipment and techniques.