ROTAVIRUSES

From Big Medical Encyclopedia

ROTAVIRUSES (Rotavirus, singular; lat. rota a wheel + viruses) — a sort of the viruses of the Reoviridae family causing an acute gastroenteritis of the person and animals.

The name Rotavirus is offered in 1974 Flyuettom (T. H. Flevvett) and sotr. The international committee on taxonomy of viruses accepted it at first for the name of group in the Reoviridae family, and in 1978 allocated R. of the person and animals in an independent family of this family.

The first among R. found and investigated the causative agent of diarrhea of white mice [Kraft (L. M of Kraft), 1957] called the EDIM virus (epizootic diarrhea of infant mice). In 1958 from material of a rectal tampon from a healthy monkey of Cercopithecus aethiops pygerythrus the similar virus — SA11 is allocated. After establishment in 1969 of the virus nature of diarrhea of calfs its activator — the NCDV virus (Nebraska calf diarrhea virus) is adapted to culture of fabric and studied by means of a supermicroscope. Close to these viruses on an antigenic structure and morphology of particles was an agent Oh, allocated from the water used for washing of guts of a livestock on a slaughter. Further the extensive group P. — causative agents of diarrheas of pigs, foals, eanlings, puppies, rabbits and deer is found and investigated.

In 1973 Australian researchers R. F. Bishop and sotr. at electronic microscopic examination of the pieces of a duodenum taken by a biopsy from the children sick with a gastroenteritis found in epithelial cells of a mucous membrane virus particles (virions) diameter apprx. 67 nanometers; after recovery the virus was not found. Similar particles were found in excrements of sick children. Use of immunoelectron microscopy with use of blood sera of patients with a gastroenteritis in the acute and rekonvalestsentny periods allowed not only to find virions in excrements, but also to establish their etiological role (see. Submicroscopy ).

Fig. 1. Elekgronogramma of virions of a rotavirus of the person in drugs of fecal suspension of the patient with a gastroenteritis (negative contrasting): and — full virions; — full (1) and incomplete (2) virions; x 50 000.
Fig. 2. Diffraction patterns of separate stages of a morphogenesis of a rotavirus of the person in culture of cells of kidneys of monkeys (the 5th passage): and — cytoplasmic inclusion of fibrous type, numerous virions in cavities endoplasmic a reticulum (it is specified by shooters), x 20 0 00; — an otpochkovyvaniye (it is specified by shooters) vrgrion (1) from a membrane of an endoplasmic reticulum (2), x 50 000; in — the located virions which gemmated vnekletochno, x 50 000.

Virions P. have spherical shape. The core of virion is surrounded with a double capsid (cover). Powerful internal to apses has structure of an ikosadeltaedr with triangulable number T-13, it is constructed of 12 pentamer and 120 hexamers consisting of 780 base units. The external capsid on negatively contrasted drugs looks a thin rim with badly distinguishable subunit structure. In fecal and cultural drugs both odnokapsidny virions P. with a diameter of 60 — 65 nanometers, and dvukhkapsidny virions to dia at the same time are found. 70 — 75 nanometers: both those, and others can be full and deprived of a core (fig. 1). Full dvukhkapsidny virions are infectious. R.'s reproduction happens in cytoplasm of cells. Early stages of a morphogenesis are connected with cytoplasmic inclusions. The virions P. forming in their peripheral sites move, gemmating from a membrane endoplasmic a reticulum (fig. 2).

R.'s genome is presented to two-filamentous RNA, in a cut 11 segments are revealed. Electrophoresis (see) in polyacrylamide gel allows to find distinctions in structure of RNA of rotaviruses of the person and separate animal species. As a part of virion P. 8 — 10 structural polypeptides are revealed. Rubles are steady against effect of solvents of fats and acid medium (pH 3,0).

The studied R. — the activator of a gastroenteritis of the person, the EDIM, NCDV, SA11 viruses and the agent About — possess the general group antigen which is a part of an internal capsid. Specific antigenic specificity of R. is defined by antigen of an external capsid; for R. of the person existence of two antigenic types is established. As a part of virions P. of calfs (NCDV), a virus of monkeys (SA11) and Ruble of the person gemagglyutiiina are found.

Rubles of animals at experimental infection actively breed in intestines and are allocated with excrements, to-rye use as a source of a virus or a viral antigen at laboratory and diagnostic testings. Separate R. of animals well breed in cultures of fabric (NGDV, SA11, the agent About, etc.). It is difficult for river of the person to adapt to an organism of any species of laboratory animals. It was succeeded to cause diarrhea peroral infection with the excrements containing R. of the person in monkeys and newborns have a stomach-nykh-gnotobiontov (pigs, eanlings and calfs). Primary infection of a cell of R. of the person is reached hardly, and the subsequent reproduction of a virus is followed by emergence of the incomplete virions deprived of an outside capsid and not capable to a reproduction. R.'s reproduction the person in cultures of cells of primacies was carried out by means of the combined influence of physical and volumetric factors (processing by trypsin and centrifuging) on a cell in an initial phase of an infection of River. Active reproduction of R. of the person in cells of primacies happens only at big concentration of full dvukhkapsidny virions in a starting material.

Carriers and R.'s sources of different types are the person and animals. It is found in sick people of R. in excrements along with emergence of symptoms of diarrhea, release of virions reaches a maximum on 3 — the 5th day of a disease. Contains in 1 g of excrements to 109 — 1010, and sometimes to 1011 virions. R.'s allocation usually lasts 7 — 8 days, seldom drags on up to 2 — 3 weeks. Rubles can be allocated with excrements and at an asymptomatic infection. Through upper respiratory tracts of R. it is not allocated, however there is a possibility of their secondary infection and spraying of a virus with an airborne way. Reliable cases of infection of the person R. from animals are unknown.

The river is an origin of a significant amount of cases of an acute gastroenteritis preferential at children in many countries of various geographical regions: by Steynkhoff's calculations (M. S. of Steinhoff, 1978) in economically developed countries not less than 50% of all cases of an acute children's gastroenteritis are caused by River. Diseases in the USSR are registered by the gastroenteritis caused by R. in a number of regions of the European part, Transcaucasia, the Urals and Siberia among children of yaselny and school age and among adults (see. Rotavirusny gastroenteritis ).

Laboratory diagnosis includes R.'s detection or its antigens in excrements of sick and specific antibodies in blood serum had (see. Virologic researches ).

See also Viruses .



Bibliography: Drozdov S. G., etc. A rotavirus of the person in culture of cells, allocation and browning, Vopr. Viru-sol., No. 4, page 389, 1979; Drozdov., Etc. Rotavirusny gastroenteritis, M., 1982; Flevett T. X. An acute not bacterial infectious gastroenteritis, the Research on comparative virology, in book: The last achievements in the area a wedge, virusol., under the editorship of A. P. Uoter-son, the lane with English, page 185, M., 1980; Holmes I. N of Viral gastroenteritis, Progr. med. Virol., v. 25, p. 1, 1979, bibliogr.; Me Nulty M. S. Rotaviruses, J. gen. Virol., v. 40, p. 1, 1978, bibliogr.; Steinhoff M. G. Rotavirus, J. Pedi-at., v. 96, p. 611, 1980, bibliogr.


S.G. Drozdov.

Яндекс.Метрика