Northern Fowl Mite (actual size 1/16 inch)
Mites That Attack Humans
Mites are small arthropods with two body regions, sucking mouthparts, no antennae, and four pairs of legs as adults. The life cycle of a mite is generally composed of four active stages: egg, larva, nymph, and adult. The life cycle usually requires one to four weeks and may result in huge populations of mites when there are favorable conditions.
Household Mites
Mites are occasionally found in homes and attack humans in the absence of their normal hosts - birds, rodents, or insects. Bites from these mites may be painful and cause severe skin irritation.
Bird Mites
The northern fowl, tropical fowl, and chicken mites are the major bird-mite species in Florida. The northern fowl mite is the species most important as a problem to birds in the state.
Northern Fowl Mite (actual size 1/16 inch)
Bird mites are usually encountered in homes when they migrate from bird nests in eaves, rafters or gutters. They prefer to feed on fledglings in the nest, but when the young leave the nest, the mites will migrate to other areas in search of a blood meal. Many times infestation of buildings occurs when roosts and nests of birds are disrupted or destroyed.
Insect Mites
The almost-invisible straw itch mite is the most prevalent insect parasite that also attacks humans. Infestations from alfalfa, hay and barley can produce irritation.
Straw itch mite (actual size 1/32 inch).
The mites are parasitic on the larvae of insects such as the angoumois grain moth, the wheat jointworm, and furniture beetles. The female mite retains up to 300 eggs in her body, and the immature stages develop to adults inside the female. Upon emerging they search for hosts to parasitize.
The bites of the straw itch mite are located almost entirely on the clothed portions of the body. Dermatitis results from reaction to the bites within twenty-four hours. Humans become infested when they come in contact with straw, grain or wood. Houses may become infested when the insect hosts of the mites are present.
Scabies Mites
The scabies mite or human itch mite burrows into the skin of humans causing human mange or scabies. Different varieties of scabies mites are specific for certain mammals including man, domestic animals, and wild animals.
The female mite makes long burrows in folds of skin. The female lays from 40 to 50 eggs in the burrow. The larvae and nymphs develop and burrow in the skin. The total life cycle takes one to three weeks depending on the environment.
Scabies Mite (actual size 1/64 inch)
Scabies mites are transmitted from one person to another by direct contact or by two persons using one bed. People are most likely to become infested when living in crowded quarters with other people. Dog scabies often can be transmitted to man.
House Dust Mites
The house dust mites (floor mites) are a little known and rarely mentioned group of mites of medical significance to humans. The importance of house dust mites is that pieces of the mites in house dust may produce allergic reactions when inhaled. It is presently estimated that four percent of the human population shows a house-dust allergy.
House dust mites feed on the shed skin of humans. It has been estimated that a normal person sheds five grams of skin per week. One gram of skin will feed thousands of mites for months.
The house dust mite is found commonly in houses and schools throughout the United States. It is believed that dust near the bed and in mattresses is the most common habitat for the mite.
House dust mites or their fragments, excretory or secretory products are the most important allergens found in house dust. Asthmatic symptoms after exposure to house dust have long been known and only recently has it been shown that the house dust mites, like pollen, can be the potential producers of allergic responses when inhaled.
Asthmatic patients who go to bed in the bedroom often realize aggravated asthmatic symptoms due to increased exposure to house dust mites. Patients who are hospitalized often dramatically improve due to less exposure.