ARENOVIRUSA (Arenavirus, singular; lat. arena sand + a virus[es]) — the RNA-containing group of the viruses having gentle granules in virion, similar to grains of sand and the general group-specific antigen.
In group A. viruses of a lymphocytic choriomeningitis (LHM), Lassa, the complex of viruses of Takaribe including viruses enter: Amapari, Machupo, Junin, Parana, Pichinde, Tamiami and Takaribe. The general group-specific antigen is found an immunofluorescence and in some cases the reaction of binding complement (RBC). Viruses of a complex of Takaribe have more close ties with each other, than with the LHM viruses and Lassa that RSK is established. The cross bonds revealed by a neutralization test or very weak, or are not found at all.
The sizes of virions, the established elektronnomikroskopichesk by method of negative contrasting, make 85 — 99 nanometers, and in ultrathin sections — from 50 to 300 nanometers. Virions have spherical shape and possess dense, well konturiruyemy, single-layer cover. The most characteristic sign And. presence in virion of various quantity of the granules similar to sand is. And. breed in cytoplasm, virus particles form budding from a regional cellular membrane. On site the cellular membrane changes, becomes more dense and more distinct than budding of a virus.
And. contain RNA, are sensitive to ether. Pier. weight And. and number of chains in structure of RNA are not determined. Reproduction And. is not suppressed with the connections detaining a reproduction of the DNA-containing viruses.
Breed in the VERO line of the intertwined cells of kidneys of green monkeys with characteristic cytopathic effect. Cause chronic, quite often lifelong infection with a virusemia in the rodents who are their feral hosts.
From 9 viruses entering into group A., pathogenicity for the person is established at four (LHM, Lassa, Machupo, Junin). The diseases caused by these viruses have essential kliniko-epidemiological distinctions.
The virus of a lymphocytic choriomeningitis (LHM)
the LHM Virus is allocated on different continents, Lass's virus in Africa, viruses of a complex of Takaribe only in South America. In the territory of the USSR only the LHM virus is revealed.
The virus of a lymphocytic choriomeningitis (LHM) is allocated by Armstrong and Lilly (Page J. Armstrong, R.D. Lillie) in 1934 from the monkey infected with suspension of a brain of the person who died from encephalitis St. Louis. The name of a virus is caused by dominance in a pathoanatomical and clinical picture of a disease of defeat of a vascular texture and a meninx with lymphoid infiltration. The size of virions, according to ultracentrifuging, is equal to 37 — 55 nanometers, and according to ultrafiltration — 48 — 60 nanometers. It is sensitive to ether, labilen at pH lower than 7,0. Not less than 8 months remains in the cold in 50% neutral glycerin, and dried up by a lyophilic method remains at t ° — 70 ° within several years.
In the conditions of experimental infection the LHM virus patogenen for monkeys, mice, Guinea pigs, dogs, rats, gray mice and chicken embryos. To a virus rabbits, pigs and birds are insensitive. In laboratory researches use the white mice and Guinea pigs finding the greatest sensitivity to intracerebral infection. The disease at white mice comes on 5 — the 7th day and is shown by slackness, irritability. At a pokruchivaniye of a tail at animals the convulsive attack which quite often comes to an end with death develops. Usually mice perish in 1 — 3 day after the beginning of a disease; the virus is found in a brain, a liver, a spleen, excrements and urine. In small percent of cases of a mouse recover and become immune to repeated infection. At transplacental infection of in utero or infection of animals soon after the birth at mice persistent infection or a latent carriage of virus develops. Originally believed that the carriage is connected with unresponsiveness, i.e. inability of an organism of mice to a specific immune response. However Oldston and Dixon (M. V. A. of Oldstone, F. J. Dixon, 1969, 1970) showed that transplatsentarno the infected mice also produce specific antibodies which are not found in a stand-at-ease because are connected with excess quantity of the virus which is in a high caption in blood and fabrics. The virus circulates in them in a complex a virus — an antibody — the complement, accumulation to-rogo in renal balls is the main reason for death of mice. Extrarenal defeats also connect with the damaging action of this complex or the cytotoxins emitted at interaction of immune lymphoid cells with a virus.
At intratserebralno the infected Guinea pigs the disease is shown by the sharp emaciation, temperature increase, conjunctivitis complicated by breath and the centers of consolidation in lungs. Animals perish usually on 7 — the 25th day after infection. At monkeys at experimental infection the disease similar to meningitis of the person develops. The virus well breeds at infection on chorion-allantoisnuyu a cover 9 — 12-day chicken embryos and it is found as on site inoculations, and in fabrics of a germ. The virus is possible to cultivate in vitro in embryonal tissues of the person, hens, mice, monkeys and other types, but the cytopathic effect can be observed only after adaptation of a virus. The LHM virus causes preferential serous meningitis in the person.
See also Choriomeningitis lymphocytic .
Lass's (Lassa) virus
Lass's (Lassa) Virus is allocated from sick people by Buckley and Kasals (S. M of Buckley, J. Casals, 1970) in of Lass in sowing. - vost. Nigeria. The disease is revealed also in Liberia and Sierra Leone.
The disease of people is characterized by fever, weakness, widespread miozita, ulcer pharyngitis, myocarditis, pneumonia, pleurisy and encephalopathy, and also displays of hemorrhagic diathesis. An incubation interval — about a week. Persons of any age are ill.
Diseases vary from the hardest, fatal cases to asymptomatic forms. The disease can be transmitted from the person to the person. The infection extends direct contact (an airborne way) or through the infected objects. Cases of laboratory infection are described. The virus is found in sick people in washouts from a nasopharynx, urine, blood and pleural liquid. The virusemia lasts not less than two weeks, the virus in urine can be found even in a month from the beginning of a disease.
Newborn mice are rather insensitive to a virus. At intracerebral infection with a high dose of a virus only at certain mice death is observed though the virus breeds in a brain and it is long it is allocated with urine. At adult mice the picture of a disease reminds a lymphocytic choriomeningitis. the virus is allocated with urine to the 83rd day after infection. Mice are unsuitable for allocation of a virus from patients; for this purpose use the VERO line of the intertwined cells in which the cytopathic effect of the activator is shown for the 4th day after infection. Fixators are found for the 52nd day from the beginning of a disease in a diagnostic caption 1: 16. Diameter of virus particles established by ultrafiltration, 70 — 150 nanometers. In RSK cross bonds with the LHM virus and with viruses of a complex of Takaribe are found. It is sensitive to a dezoksikholat of sodium, contains lipids in an external cover.
See also Lassa fever .
Viruses of a complex of Takaribe
Viruses of a complex of Takaribe are characterized by the following properties: a) irregular pathogenicity for newborn mice and more homogeneous pathogenicity for newborn hamsters; b) a long virusemia at natural owners rodents; c) sensitivity to a dezoksikholat of sodium; d) difficulty of identification of virus neutralizing antibodies in the serums containing fixators.
Takaribe's virus (Tacaribe) is allocated by W. G. Downs with sotr: in 1956 on the lake of Trinidad from the crushed mix of 8 species of mosquitoes, and also from a brain and sialadens of bats by infection of newborn mice. Newborn and adult mice, and also newborn hamsters, to intraperitoneal — only newborn mice and hamsters are sensitive to intracerebral infection. In cells of a brain white and the bats infected with Takaribe's virus cytoplasmic inclusions come to light. Takaribe's virus patogenen at infection of 6-day chicken embryos in a vitellicle, causing death of some of them on 7 — the 8th day. The virus breeds in kidneys of the Syrian hamster with weak cytopathic effect, and with the expressed changes — in cells of VERO.
Junin virus (Junin) — the causative agent of the Argentina hemorrhagic fever, is allocated to A. S. Parodi with sotr. in 1958 in the province Buenos Aires from sick people. Besides, it is allocated from mites of Echinolaelaps echidninus, from field rodents of Hesperomys laucha and Acodon arenicolli, and also from house mice of Mus musculus.
The disease at people is characterized by fever, rash, hemorrhages, leukemia and an albuminuria. Pages are ill preferential - x. workers of young age, generally men during the period from April to August. A lethality — apprx. 20%. In nature the virus circulates between rodents and, apparently, mites.
The sizes of a virus apprx. 100 nanometers. A virus patogenen for newborn mice at infection in a brain and under skin.
The incubation makes 8 — 20 days. Breeds with cytopathic effect in culture of cells of HeLa. In protoplasm of the infected cells basphilic inclusions are found. The specific antigen in the infected cells well comes to light by method of an immunofluorescence. The hemagglutinating antigen did not manage to be prepared, complement-linked antigen is prepared by method of saccharose and acetonic extraction from a brain of mice for the 7th day after infection.
See also South American hemorrhagic fevers .
Machupo's (Machupo) virus
Machupo's (Machupo) Virus — the causative agent of the Bolivian hemorrhagic fever, is allocated by Johnson (K. M of Johnson) with sotr. in 1963 from sick people and rodents of Calomys callosus.
The disease at people is clinically similar to the Argentina hemorrhagic fever. Lethality high. Due to a possibility of laboratory infection work with the activator demands especially high security. Infection of people results from contact with rodents or the objects infected with their allocations. Destruction of rodents leads to the termination of diseases.
The sizes of a virus 120 — 180 nanometers. It is sensitive to a dezoksikholat of sodium. The newborn hamsters and mice who are getting sick at intracerebral and intraperitoneal infection in
7 — 18 days are most susceptible to a virus. Titres of a virus in a brain and a spleen of animals reach 10 7 — 10 8 LD 50 . At adult hamsters, just as at rodents of Calomys callosus, hron, the infection with allocation of a virus with urine lasting more than 7 months often develops.
The virus breeds in a strain of diploid cells of WI-26 with full cytopathic effect on 9 — the 14th day after infection.
In culture of MA-III under an agar the virus forms plaques. The hemagglutinating antigen is received from blood serum, and complement-linked antigen — from a brain of the infected mice.
See also South American hemorrhagic fevers .
Tamiami's virus (Tamiami) is allocated to J. Davie in 1965 in the Southern Florida (USA) and in 1970 by C. H. Calisher with sotr. from adult males of cotton rats of a type of Sygmodon hispidus caught about Tamiami Road. The virus is allocated by intracerebral infection 2 — 4-day mice at whom encephalomyelitis with symptoms of drowsiness, lack of appetite develops. ataxy and prostration. Animals perish on 9 — the 16th day after infection. A virus patogenen also for 3 — 4 weeks mice at whom the disease from the death after intracerebral infection arises in 15 — 20 days. Cotton rats do not perish, but at them, just as at 3 — 4 weeks hamsters, concentration of a virus in a brain reaches 10 6 — 10 7 LD 50 . Poorly patogenen for white rats. The virus is sensitive to a dezoksikholat of sodium, termolabilen. In a brain suspension it is inactivated at t°56 ° in 10 min., at t ° 37 ° in 3 days, at t ° 25 ° in 7 days, at t ° 4 ° in 90 days, at t ° — 60 ° viability does not decrease within not less than 3 months. The virus but agglutinates erythrocytes of the person, a Guinea pig, sheep, mice, green monkeys and geese at pH 5,9 — 7,2 and t ° 4 — 37 °. The virus was not allocated from 2 million mosquitoes caught in the same area. Apparently, mosquitoes are not feral hosts of a virus.
Amapari's virus (Amapari) is allocated from rodents and from the ticks who are brought together on them in 1964 to Pineyru (f. P. Pinheiro) in Brazil, to the North from the mouth of the Amazon River, near the river of Amapari. The prototype strain is allocated from mix of bodies of rodents of Neacomys guianae. In the subsequent the virus was allocated also from rodents of Oryzomys capito and from the ticks who are brought together on them. A virus patogenen for newborn mice at whom the virusemia develops. Breeds in cellular cultures of VERO and V of NK-21 without the expressed cytopathic effect.
Parana virus (Parana) is allocated by Webb (P. A. Webb, 1970) with sotr. from tissues of rodents of Oryzomys buccinatus near the Parana River separating Paraguay from Brazil and Argentina. It is allocated from kidneys of animals by intracerebral infection of newborn hamsters. The incubation interval at hamsters is equal to 8 — 11 days. The virus patogenen and for newborn mice, however a titre of a virus in a brain of mice is lower, than at hamsters. From all viruses of a complex of Takaribe the Parana virus least patogenen for mice. Antibodies in blood serum of people to the Parana virus are not revealed.
Virus of Pichinde (Pichinde) is allocated by Trapido and Sanmartin (N. to Trapido, C. Sanmartin, 1971) in Colombia, in the valley of river of Pichinde from rodents of Oryzomys albigularis. One strain is allocated also from rodents of Tromasomys fuscatus. Despite broad inspections of ectoparasites, a virus it was found only in isolated cases. Believe that its finds at mites are caused only by a virusemia at animals, and ticks are not feral hosts of a virus. The virus in blood of animals comes to light even in 455 days after infection, however it is not found in urine. Infectiousness of rodents makes about 20%, and the virus is allocated for all year. Pichinde's virus patogenen for newborn mice and hamsters at whom after 7 — 18 days of an incubation (7 — 12 days are more often) the fatal disease develops. Hamsters survive seldom, mice more rezistentna, do not find in some symptoms of a disease. At infection with a high dose of a virus newborn mice perish from a toxaemia during the first 24 hours, and adult mice to it are insensitive. Pichinde's virus breeds in cells of VERO with the expressed cytopathic effect which appears for the 4th day and completely comes to the end on 6 — the 7th day. Newborns are equally suitable for allocation of a virus. mice, hamsters and cells of VERO. Fixators to Pichinde's virus are revealed in blood serum of the people having contact with rodents by the nature of the work.
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T. A. Bektemirov.