From Big Medical Encyclopedia

GAMAZOIDNY MITES (Gamasoidea; synonym gamazovy mites) — the superfamily of mites of Parasitiformes Zachy group combining St. 20 families and more than 300 childbirth. Nek-ry types of G. to. are carriers or participate in circulation in the natural centers of activators of a number of infectious diseases. Free living views from the families Rhodacaridae, Parasitidae, Veigaiaidae, Macrochelidae, Phytoseiidae and parasitic types of the Laelaptidae, Haemogamasidae, Hirstionyssidae, Macronyssidae, Dermanyssidae, Spinturnicidae, Rhinonyssidae, Entonyssidae and Halarachnidae families are eurysynusic.

Females of gamazoidny mites: 1 — chicken (full size — 0,84 mm); 2 — mouse (full size — 1,6 mm); 3 — rat (full size — 1,1 mm).

To. — small (0,2 — 2,5 mm) yellowish-brown coloring, blood-sicking types — scarlet, in process of digestion of blood darken. A body oval with 4 pairs of legs and terminalno the located oral device. Representatives of different families differ as morphologically, and on a way of life. Predatory G. to. grab and break off production, and parasitic — make an incision or pierce leather of an animal-prokormitelya. Legs shestichlenikovy with claws and a sucker. The body is covered with guards; at males belly guards are usually merged, the genital opening in the form of a funnel is at a first line of a genital guard. G. breathe to. by means of the tracheas opening stigmas (stigmata). On a body and extremities there is a set of bristles, constant on number and situation. To. lay eggs, nek-ry it is viviparous. A development cycle of G. to. develops of five phases: egg, larva, protonymph, deytonimfa and puberal tick. At a larva three pairs of legs, guards are underdeveloped, stigmas are absent protonymphs four pairs of legs, guards are clear, the back guard consists of two parts, a stigma with short peritrema; the deytonimfa resembles puberal ticks with yet not issued outside sexual device superficially. At all parasitic G. to. the larva does not eat, at representatives of Macronyssidae does not eat as well a deytonimfa; nek-ry representatives have Laelaptidae and Haemogamasidae — the first eating phase — a deytonimfa. Duration of all development cycle averages 12 — 15 days; for G.'s season to. can give dozens of generations. All G. to. vlagolyubiva (optimum relative humidity of 70 — 100%) also transfer fluctuations of temperatures in wide limits (from 5 — 8 ° to 28 — 35 °).

Free living G. to. live in top coats of the soil, a forest floor, on plants, mushrooms, under bark of trees, in the decaying remains, manure, etc. Eat small arthropods, nematodes etc. For the resettlement can use animals and insects (a so-called phoresia).

Parasitic G. to. are connected with insects, snakes, lizards, birds, rodents, insectivorous, small predators and bats; separate types live in lungs, a nasal cavity and frontal sinuses of birds, bronchial tubes of walruses, seals and other Pinnipedia, dogs and monkeys, in an outside ear of cattle etc. The nature of communication with an animal, as well as type of food, at parasitic G. to. various: among them are available nested, vneubezhishchny, epizoyny (constantly living on the owner) and band parasites (see). The main source of food — blood of an animal-prokormitelya; are reckoned, at to-rykh the food mixed. They combine a gematofagiya with entomophagy (optional bloodsuckers). Nek-ry types of G. to. are capable to suck blood at the person.

Free living, optional bloodsuckers and constant parasites eat repeatedly; the female during maturing of eggs eats more often. Nested and vneubezhishchny parasites at certain stages of development eat blood once. Females after a yaytsekladka are capable to a repeated krovososaniye, development in their body of a portion of eggs happens to digestion of blood (gonotrofichesky harmony). Between the main types of parasitism at G. to. transitional forms are had: from free living predators to obligate bloodsuckers, from nested and vneubezhishchny — to constantly living on a body of the owner or in his respiratory tracts. Thanks to existence of transitional forms of G. to. have comparative parazitol. interest also allow to track evolution of parasitism.

To. are eurysynusic, meet in all parts of the world and different landscape zones and vertical belts, their species composition in a forest zone is especially rich. G.'s most to. actively round the clock; rise in number at different types and groups is not identical — at predatory forms is defined by the greatest security with food, and at parasitic types biology of the owner and a microclimate of a nest.

In developing of transmissible diseases of the person chicken, mouse, rat mites (fig.) have the greatest value. The chicken tick (Dermanyssus gallinae) lives in hen houses, nests of pigeons, in cells of room birds; a nested parasite, the obligate bloodsucker, it is long starves, remaining in cracks of rooms. The mouse tick (Allodermanyssus sanguineus) in biology is similar to chicken, is connected with rodents, is widespread in the southern areas, willingly breeds in the dwelling of the person. The rat tick (Ornithonyssus bacoti) — by origin a tropical look — extended together with a rat brown rat in the whole world, in midlatitudes settles in inhabited and economic constructions. Chicken G. to., intensively breeding in the spring and in the summer, do harm to poultry farming, reduce egg production, stings of mites weaken and ruin baby birds. Stings of rat, mouse and chicken mites cause in people (especially at children) acute dermatitis, to-rye sometimes is followed by high temperature.

Epidemiol, value G. to. is studied insufficiently. The role of mouse and rat mites in the centers of a vesicular (ospovidny) rickettsiosis is clearest (see. Vesicular rickettsiosis ). Both look — keepers and carriers of the activator of a vesicular rickettsiosis; transovarial and transphase transfer of the activator is proved. In houses where found these ticks, cases of a vesicular rickettsiosis took place. Obviously, a similar role is played by a rat tick in the centers of local rat typhus (Rickettsia mooseri activator). Allocation of strains of activators from different types and groups G. to., and also experiments with separate species of mites and causative agents of diseases allow to assume participation of nek-ry types of G. to. in circulation of causative agents of such prirodnoochagovy diseases, as a tick-borne rickettsiosis of Northern Asia, the Q fever, encephalitis St. Louis, the Western and East encephalomyelitis of horses, a tick-borne encephalitis, a tularemia and plague.

Short epidemiol, the characteristic of the most widespread types of G. to. it is provided in the table. In the natural centers of G. to. have hl. obr. epizootological value since their most part is connected with small mammals and birds. The person is attacked by preferential synanthropic types, against to-rykh and measures of fight are developed. With mouse and rat mites carry out fight by destruction of rodents (see Deratization) with simultaneous improvement and clearing of the territory and processing of rooms acaricides (see). Fight against bird's mites is based on periodic (2-4-fold) processing by various acaricides (nicotine, a lindane, etc.) rooms and birds. It is also necessary to observe the precautionary measures entering the general complex of actions for protection of the person against parasites and carriers transmissible diseases (see).

See also Mites .


  • Types are located depending on their epidemiological


Bibliogr. Bregetova of N. G. Gamazovye mites (Gamasoidea), M. — L., 1956; Territorial A. A. Gamazovye mites (Gamasoidea), in book: Carriers of causative agents of prirodnoochagovy diseases, under the editorship of P. A. Petrishcheva, page 291, M., 1962; it, Parasitic gamazovy mites and their medical value, M., 1973; Kiselyov R. I. Ospopodobny rickettsiosis, Kiev, 1964; Determinant of the arthropods damaging health of the person under the editorship of V. N. Beklemishev, page 197, M., 1958; Romasheva L. F. and To the expert and e in S. K. Ectoparasites of poultry and fight against them, Frunze, 1961; Chistyakov A. F. A rat tick and dermatitis at people, L., 1960.

A. A. Zemskaya.