Ohio State University Extension Fact Sheet

Ohio State University Extension Fact Sheet


1991 Kenny Road, Columbus, Ohio 43210-1090

Mites Annoying Humans


William F. Lyon
W. Calvin Welbourn

Common NameScientific Name
Northern Fowl MiteOrnithonyssus sylviarum (C.and F.)
Chicken MiteDermanyssus gallinae (DeGeer)
Tropical Rat MiteOrnithonyssus bacoti (Hirst)
House Mouse MiteLiponyssoides sanuineus (Hirst)
Follicle MiteDemodex folliculorum (Simon)
Itch or Scabies MiteSarcoptes scabiei hominis (Hering)
Straw Itch MitePyemotes tritici
Grain MiteAcarus siro L.
Mold MiteTyrophagus putrescentiae (Schrank)
House Dust MiteDermatophagoides sp.

Certain mites migrate from birds, rodents, food materials, vegetable matter and house dust, either attacking or annoying humans. Some mites can be detected with a hand lens, while others require microscopic examination of skin scraping or even dust from vacuum cleaner bags. Mite irritations can be confused with entomophobia (fear of insects) in certain people. Mite diagnosis is often difficult because specimens must be collected and identified by trained specialists before treatment can be made.

House Dust Mite


Most mites are 1/200 to 1/25 inch long, oval, without antennae and grayish-black to red. Their mouthparts are grouped in front of the body, resembling a head. Adult mites have four pairs of legs. The follicle mite is more worm-like. Some mites appear as barely visible red and gray, slow-moving specks, while others are microscopic, requiring optical equipment for identification.

Life Cycle and Habits

Northern Fowl Mite

This barely visible mite completes development on the host bird (i.e., poultry, pigeons and starlings) and will leave the body of a dead host in large numbers to wander over walls, ceilings and bedding, seeking a new host. Bites can cause itching and dermatitis. This mite can survive two to three weeks away from the host.

Chicken Mite

This mite feeds on the host at night and hides in cracks and crevices during the day. It feeds on poultry, sparrows, canaries and other birds. A new generation may occur every 7 to 10 days. Bites cause itching and light dermatitis. These mites enter a house after death of the host bird or departure from the nest. They can live for a month or more without a blood meal.

Tropical Rat Mite

This mite will feed on humans even when rats are present, causing painful bites, intense itching and dermatitis. Barely visible, they are bright red to black with white markings and are usually noticed on walls in basements, kitchens, bathrooms and where rats are found. Mites drop from their host after each blood meal and can survive several days without feeding.

House Mouse Mite

This mite is found on mice and can bite humans. It will wander away from mice onto walls.

Follicle Mite

These microscopic mites live in the hair follicles or sebaceous glands of most humans. Very few persons are allergic to them. Those who are may lose their eyelashes or develop acne.

Itch or Scabies Mite

This mite is similar to those that attack livestock, horses, dogs and rabbits. Transmission is usually by direct contact with an infested person. Itch mites tunnel into the skin, especially on hands and wrists. Nodules burst and ooze serum, later hardening to form scabs. The skin between the fingers is often invaded. Itching is intense and known as "scabies" or "seven-year itch." Scratching can cause bleeding and infection of open sores. Overlapping generations occur at two to three week intervals.

Straw Itch Mite

These mites can cause epidemics of dermatitis during harvesting and post-harvesting operations in straw, hay or certain grains. Bites produce a rash-like dermatitis, extending over much of the body and accompanied by itching, sweating, fever, headache and even vomiting in severe cases. They are beneficial because they feed on larvae of wheat jointworm, rice and granary weevils, Angoumois grain moths and other pests.

Grain and Mold Mites

These mites can be found in a wide variety of stored products and food and can cause mild dermatitis known as "grocer's itch." Heavy infestations have a sweet or minty odor. A coating of "mite dust," molted skins of the mites, covers the infested grain or cheese. Sometimes the surface of infested materials appears to move due to large numbers of mites. These mites favor damp areas. They do not bite humans.

House Dust Mite

These mites are found in mattresses, pillows and furniture containing natural fibers. They are scavengers that feed on human skin scales and other detritus but do not bite humans. About 90% of the persons allergic to house dust extracts are allergic to house dust mite extracts. Only about 10% of those not allergic to house dust extract are allergic to the dust mite extract. Over half of all homes are believed to be infested with the house dust mite.

Control Measures

For bird and rat mites, standard insect repellents such as diethyl meta-toluamide (deet), ethyl hexanediol or dimethyl phthalate will prevent bites. Locate and remove bird and rodent nests, and treat infested areas with household crawling insect sprays of malathion, diazinon or Baygon. A vacuum cleaner will collect many mites. Dispose of sweeper bag contents. For grain and mold mites, store materials moderately dry (130 degrees F and low relative humidity). Discard infested foodstuffs and clean premises. Treat storage areas with pyrethrins, malathion or resmethrin. Before using insecticides, read the label and follow directions. Infested grains and cheese in food handling institutions must be fumigated only by licensed, certified pest control applicators. For treatment of scabies, dermatitis and other skin disorders, contact a physician.

All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.

Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.

TDD No. 800-589-8292 (Ohio only) or 614-292-6181

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