Mites

Author:Prof. Dr. med. Peter Altmeyer

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Last updated on: 29.10.2020

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Synonym(s)

Acari

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DefinitionThis section has been translated automatically.

All mites (Acari, about 10,000 species) belong to the arthropods (arthropods) and here to the arachnids (Arachnida). They are divided into a number of orders, especially with regard to the formation of their respiratory openings (astigmata: no respiratory openings; prostigmata: respiratory openings in front, cryptostigmata: respiratory openings hidden, mesostigmata: respiratory openings in the middle, metastigmata: respiratory openings behind).

In addition to their infectiological significance in the transmission of various pathogens (e.g. rickettsialpox, tsutsugamushi fever), they can cause skin lesions through bites.

The mites most frequently responsible for allergic diseases belong to the superfamilies Pyroglyphphoidea with house dust mites (Dermatophagoides pteronyssinus, Dermatophagoides farinae, Euroglyphus maynei) and Acarideae(storage mites).

General definitionThis section has been translated automatically.

  • Human Scabious Mite: The 400 x 300 μm large (Acarus siro var. hominis or Sarcoptes scabiei hominis) has four pairs of legs and very strong jaws. The only host is the human being. Mites survive outside the host (e.g. in clothing and bedding) for 2-3 days. On average, a patient accommodates only 11.3 (!) adult female mites. 3% of the patients have > than 50 mites, the maximum being about 500. For the infestation of a new victim a single mated female is sufficient.
  • Generation cycle of the human dross mites:
    • Multi-stage metamorphosis. The total development time for males is 9-14 days, for females 12-21 days.
    • Female mites are able to move about 2.5 cm/min. on the human skin and drill blind ending corridors parallel to the skin surface into the horny layer. Since the mites breathe through the body surface, they can only penetrate as far as the stratum corneum and not deeper. Only 1 female mite lives in each passage. They feed on drilled skin, lengthen the passage daily by about 0.5-5 mm and lay 2-3 eggs/day as well as debritus and faeces in the passage. 3-7 days later larvae hatch from the eggs. In search of food, larvae leave their passage, shed their skin after about 3 days and reach the protonymph stage. 3 days later, protonymphs either shed their skin and differentiate into adult male mites or enter a second nymph stage (tritonymphs). From tritonymphs either adult sexually mature males or females develop. Adult mites mate on the skin surface or in short (< 1 mm) ducts drilled for mating alone.

PathogenThis section has been translated automatically.

  • Herb mite (Sarcoptes scabiei var. hominis): Clinic: see below scabies. Worldwide occurrence, usually transmitted directly by physical contact, more rarely also indirectly, e.g. by bedding in hotels.
  • Dog mite ( Sarcoptes scabiei var. canis): Worldwide occurrence, living on dogs and causing mange there. Passes over to humans in close contact.
  • Horse Cattle Cat Mite: Man is, just as in the case of dogs, also a false host in the case of cat ruff and horse scabies, mites cannot settle down and perish ( pseudoskabies); see mange below.
  • Bird mite (Dermanyssus avium): Worldwide occurrence, especially in chickens, also in pigeons and various songbirds, in stables and nests. The mites can, under certain circumstances, penetrate into the house through windows of the ventilation systems. Man is a false host (see below gamasidiosis).
  • (Tropical rat mite (Ornithonyssus bacoti ): Occurs in tropical countries, also in Europe. Man is a false host.
  • Grave mite (Trixacarus caviae): most common dermatosis (Sarccoptes mange) in small mammals (rabbits, guinea pigs). Rarely transmitted to humans in close contact with infested animals.
  • Cheyletiella mite (Cheyletiella yasguri): Occurs worldwide in dogs, rabbits, hares, cats, rarely passes to humans in close contact with infested animals S.u. Cheyletiellosis.
  • Harvest mite (Trombicula autumnalis): In Europe mainly in autumn. Humans are attacked by the larvae when walking in the Alps (Clinic: Trombidiosis).
  • Grain beetle mite (Pyemotes ventricosus): Occurs mainly in Mediterranean countries and in Northern Europe. The mite feeds on cereal pests and is therefore found in grain stores, barns and on straw mattresses. Woodworms are also infested.
  • Other mite species:

Clinical pictureThis section has been translated automatically.

LiteratureThis section has been translated automatically.

  1. Arbes SJ Jr (2003) House dust mite allergen in US beds: results from the First National Survey of Lead and Allergens in Housing. J Allergy Clin Immunol 111: 408-414
  2. Custovic A et al (2003) Current mite, cat, and dog allergen exposure, pet ownership, and sensitization to inhalant allergens in adults. J Allergy Clin Immunol 111: 402-407
  3. Mumcuoglu Y et al.(1979) Infestation of humans by Sarcoptes scabiei var. bovis (bovine room mite). dermatologist 30: 423-426
  4. Stüttgen G, Haas H, Mittelbach F, Rudolph P (1982) Environmental dermatoses. Springer, Vienna New York, S. 282-286
  5. Thomas WR, Smith W (1998) House-dust-mite-allergenic. Allergy 53: 821-832

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Last updated on: 29.10.2020