From Big Medical Encyclopedia

SKREBNI (synonym: Acanthocephala, akantotsefala) — pervichnopolostny helminths like Acanthocephales, the class Acanthocephala; inhabitants of intestines of vertebrate animals, and sometimes and person. In total there is apprx. 500 types of S. Telo skrebnya (fig. 1) usually cylindrical, extended, sometimes slightly flattened; it is subdivided into two departments — front (presoma) and back (metacatfish). Length of a body varies from 1,5 mm at parasites of fishes — neoyekhinorinkhid — to 650 mm at parasites of pigs — skrebney-giants. On the front end there is a proboscis (fig. 2) armed hi-tinizirovanny kryuchyam, with the help to-rykh a parasite is attached to a wall of intestines. Cover fabrics C. consist of a thin epikutikula, a cuticle and a powerful hypoderma, under a cut ring and longitudinal muscle fibers are located. Covers of the majority of types of S. participate in processes of nutritive absorption in intestines of the owner, and also in processes of allocation of end products of exchange.

Fig. 1. Diagrammatic representation of a structure skrebnya Polymorphus magnus: 1 — a proboscis from a kryuchyama; 2 — a neck; 3 — seed plants; 4 — cement glands; 5 — a cuticle; 6 — a muscular bag; 7 — channels of cement glands; 8 — coital body.
Fig. 2. Diagrammatic representation of proboscises skrebny different types: and — Acanthocephalus anguillae; 6 - Echinorhynchus gad i; in — Filicollis anatis. Are visible hitinizirovanny kryuchya by means of which skrebn are attached to a wall of intestines of the owner.

The nervous system is presented by an unpaired head ganglion, from to-rogo several pair nervous trunks depart. Males, besides, have a pair sexual ganglion with the nerves departing from it innervating output ways of a reproductive system. Sense bodys are developed poorly. Page — diclinous animals. Embryonic development of S. proceeds in a perigastrium of females and comes to an end with formation of egg with an embryonal larva (akantor). S.'s development happens with metamorphosis (see) and always with change of owners (nek-ry types of S. have two and even four intermediate owners).

S.'s parasitizing in a kishechnnka of domestic animals is followed by ponosa with blood, loss of appetite, falloff of weight; at a perforation of intestines animals perish. That S. do big harm to pig-breeding (e.g., S. of a type of Macracanthorhynchus hiru-dinaceus), to fur farming (S. of a type of Macracanthorhynchus catulinus), to poultry farming (S. of a type of Polymorphus magnus, etc.), and also to fishery (S. of types of Echinorhynchus gadi, Metechinorhynchus salmonis, etc.). Meat of domestic animals, at to-rykh S. are revealed, does not demand special processing and can be eaten.

Pages are not obligate parasites of the person though exceptional cases of detection of a scraped-nya-giant and necklace-shaped S. at the person are known. In 1888 the ital. scientist S. Calandruccio for the purpose of autoinfection swallowed several larvae of S. of a type of Moniliformis moniliformis. Symptoms of a disease (intestines pains, a diarrhea, the general weakness) were shown in three weeks. After treatment extract of a men's fern allocated 53 mature S. and there came the absolute recovery.

See also Akantotsefaleza .

Bibliography: Bogoyavlensky Yu. K. and Ivanova G. V. Microstructure of fabrics skrebny, M., 1978, bibliogr.; D au g e l V. A. Zoologiya of invertebrates, M., 1981; Petrochenko of V. I. Akan-totsefala (skrebna) house and wildings, t. 1 — 2, M., 1956 — 1958; Schultz R. S. and Gvozdev E. V. Bases of the general helminthology, t. 1, page 320, M., 1970.

Yu. K. Bogoyavlensky.