REOVIRUSES (Reoviridae) - the RNK-soderzhashchnkh family of viruses combining viruses of the person, animals, arthropods and plants.
The family P. includes 5 childbirth — Reovirus, Orbivirus, Rotavirus, Phytoreovirus and Fijivirus. Virions of the viruses entering into family P. possess ikosaedralny structure, diameter them fluctuates within 60 — 80 nanometers, they have no lipoproteidny cover, but contain a two-layer fibrous casing, expressiveness and a structure of layers the cut varies at various representatives of family. At virions of representatives of the sorts Reovirus and Rotavirus in each of layers of a cover base units — capsomeres (fig., a) come to light that allows to carry viruses of this childbirth to the two-shell (or dvukhkapsidny). At virions of representatives of the sorts Orbivirus and Phytoreovirus the kapsomerny structure of an enveloping layer of a cover is expressed indistinctly (fig., b) therefore they are described as odnokapsidny viruses. The structure of a kapsidny layer of virions of representatives of the sort Fijivirus is studied insufficiently. Virions P. contain fragmented (10 — 12 fragments) the two-filamentous RNA making 14 — 22% of mass of virion, 6 — 10 polypeptides including transcriptase and other enzymes.
The name P. (from English respiratory respiratory, enteric intestinal, orphan orphan) is given by A. Sabin, in 1959 for the first time described the new group of viruses classified further as the independent sort Reovirus under this name. In 1971 Mr. Borden (E. S. of Borden), R. Shoup and F. A. Murphy revealed strong likeness physical. - chemical properties and morphology of particles of many representatives arbovirus (see) with the virus of «blue language» of sheep which is well studied earlier also suggested to combine them in one taxonomical group of orbivirus (Latin of orbis a ring), allocated further in the sort Orbivirus. 84 viruses entering into 17 subgroups combining antigenically related viruses, and 6 nesgruppi-rovanny viruses belong to the sort Orbivirus. To orbivirusa, pathogenic for the person, viruses of Changuinola, Kemerovo and Tribech, defiant not numerous cases of ostrolikhoradochny diseases, and a virus of tick-borne fever of Colorado belong (see. Colorado fever ). In some cases feverish diseases in Africa the etiological role of orbivirus of Lebombo and Orunga is established. A number of orbivirus causes diseases of animals — infectious catarral fever of sheep («blue language»), an epizootic hemorrhagic disease of deer, the African plague of horses and an ostrolikhoradochny disease of cattle (fever of Ibaraki).
As as a part of particles of the viruses belonging to the sorts Reovirus and Orbivirus two-filamentous RNA contains, Fervurd (D. W. Verwoerd, 1970) suggested to combine them in one family of «diplornavirus» (from Greek diploos of double and English RNA — RNA), however the name of recognition did not receive.
In 1978. The international committee on taxonomy of viruses allocated as a part of family P. three new sorts — Rotavirus, Phytoreovirus and Fijivirus. To the sort Rotavirus (see. Rotaviruses ) the activators of an acute gastroenteritis of the person which were intensively studied in 1974 — 1978 were carried (see. Rotavirusny gastroenteritis ) and many animal species — cattle, white mice, Guinea pigs, sheep, goats, pigs, monkeys, horses, antelopes, bisons, deer, rabbits and dogs. Particles of rotaviruses have the dvukhkapsidny structure different from structure of representatives of the sort Reovirus more accurate expressiveness of an outside kapsidny layer, and 11-fragment RNA. Rhoda Phytoreovirus (Greek phyton a plant) and Fijivirus (according to the name of the Fiji Islands where the virus which became a prototype of a sort causing a disease of a sugarcane was found) combine viruses, pathogenic for plants.
Actually R. — representatives of the sort Reovirus — make small group of viruses. The first representative of a sort was allocated and described Ramos-Alvares (M. by Ramos-Alvarzs) and Seybin in 1954 as one of types of enteroviruses of the person — ECHO-10, however by much big sizes and some other physical. - chemical and biol. properties it is carried further to independent group P. The numerous strains of representatives of the sort Reovi-rus allocated from people, monkeys and many species of the lowest mammals were belonging to 3 antigenically various types — 1, 2 and 3. The strains of one type allocated from the person and animals do not differ from each other. The main properties of virions of representatives of the sort Reovirus correspond to the properties characterizing family P. Virions of a sort have spherical shape, possess two capsids; the size of virions makes 75 — 80 nanometers. Two-filamentous RNA of viruses of the sort Reovirus consists of 10 fragments, her general a pier. weight makes 14 — 15 X 106, as a part of the mass of virion it occupies 14%. Virion includes 9 polypeptides about a pier. weighing 34 — 155 X 103, to-rykh are a part transcriptase and a nukleotidfosfogidrolaza. Viruses are steady against effect of ether and other solvents of fats, are rather steady against heating, action of an ultraviolet light and usual desinfectants, keep activity in a wide interval of pH, including and at pH 3,0. Like enteroviruses, they gain the increased resistance to heating in 1 M solution of magnesium chloride (the infectious titre of a virus does not go down at t °50 ° within 1 hour).
Reproduction of viruses of the sort Reovirus happens in cytoplasm of susceptible cells where at a reovi-rusny infection cytoplasmic perinuclear inclusions are formed, in to-rykh, apparently, and formation of virus particles is carried out. In vitro viruses well breed and cause cytopathic effect in cultures of cells of many species of primacies and domestic animals. To allocation and a research of viruses apply cultures of cells of kidneys of monkeys of macaques Rhesus factors or tserkopitek, and also primary cultures of cells of kidneys of an embryo of the person or the intertwined lines of cells of human amnion, HeLa, BS-C-1; as experimental animals most often use white mice suckers.
Viruses of the sort Reovirus have ability to agglutinate erythrocytes of the person therefore reaction of suppression of hemagglutination finds broad application both for identification and antigenic group P., and for the diagnostic purposes (see. Virologic researches , Serological researches ).
Rubles of the sort Reovirus of three types are eurysynusic in all areas of the globe on what specifies detection of antibodies in blood sera of people and animals at mass inspections. Among mammal R. have a wide range of owners and infect under natural conditions mice, rabbits, cats, dogs, pigs, sheep, cattle, monkeys of macaques Rhesus factors, tserkopitek and a chimpanzee, several species of the American monkeys and other animals. As R. of each of types allocated from the person and animals are indiscernible, the issue is still not resolved whether there are options P. of animals and R. of the person and if do not exist whether then the person is primary owner R. or they shall be considered as the viruses of animals capable to infect the person. The infected animals (as well as the person) allocate a virus with excrements, to-rye infections of the person can be a source. River, it is plentiful and long allocated with excrements of the infected cows, can get to milk. In a similar way excrement of other animal species infected with R. many foodstuff can become soiled. Preservation of a virus in the infected products can be promoted by that circumstance that the greatest spread of a reovirusny infection is observed in autumn and winter months.
R.'s role in an etiology of a number of diseases, with to-rymi they communicate, remains still not clear. Often reovirusny infection of the person proceeds asymptomatically. At the same time various types P. were allocated from patients with feverish diseases, ekzantematoza, acute diseases of top and bottom respiratory tracts (including with the phenomena of intersticial pneumonia), went. - kish. a path (including a steatorrhea) and c. N of page (from easy symptoms to encephalitis). The ruble is possible to allocate from patients from nasopharyngeal separated or from excrements. In some cases long excretion of R. with excrements and emergence in the course of an infection of specific antibodies is noted. However frequent development of an asymptomatic reovirusny infection and wide variability a wedge, the symptoms developing on a background of infection of an organism of R. can indicate also that R. in some cases is not the etiological, and accompanying agent. Experimental infection of R. of animals (white mice, dogs) causes in some cases intersticial pneumonia, a steatorrhea, jaundice. At monkeys of the macaques infected with R. of types 1 and 2 the phenomena of meningitis were noted, and at these animal R.' infection type 3 — symptoms of hepatitis. At the same time convincing data on R.'s role in pathology of the person are absent.
Bibliography: Laboratory diagnosis of viral and rickettsial diseases, under the editorship of E. Lennet and N. Schmidt, the lane with English, page 285, M., 1974; Fenner F., etc. Biology of viruses of animals, the lane with English, t. 1, page 185, 351, M., 1977; Matthews R. E. F. Classification and nomenclature of viruses, Intervirology, v. 12, p. 130, 1979; Viral and rickettsial infections of man, ed. by F. L. Horsfall a. I. Tamm, p. 569, Philadelphia, 1905.
S.G. Drozdov, I. G. Balangding.