[Variants of the immunoreactivity and infectious process in bank vole (Myodes glareolus) experimentally infected with the hantavirus Puumala (PUUV)].

As a result of a longitudinal study of the Puumala hantavirus (PUUV) in the experimentally infected bank voles (Myodes glareolus), we revealed three groups of the voles differing in the immunoreactivity and viral antigen concentration in the organs. The close correlation between these parameters suggested the existence of various mechanisms of the hantavirus persistence in the host.

[Synthesis of virus-specific products following introduction of tobacco mosaic virus RNA pereparations and the native virus into acetabularia]. / Izuchenie sinteza virusspetsificheskikh produktov posle vvedeniia v atsetabuliariiu preparatov RNK virusa tabachnoi mozaiki i nativnogo virusa.

The possibility to synthesize the viral-specific products after microinjection of Tobacco mosaic virus (TMV) preparations and the TMV RNA into the single-celled seaweed Acetabularia was studied. The accumulation of the newly synthesized protein and double-stranded RNA 24 hours after injection of TMV RNA and native virus preparations was demonstrated by immunological and immunofluorescent methods. The virus titer sharply dropped 3--4 hours after introduction into Acetabularia and in 48 hours it reached a maximum level. The presented data showed the possibility of TMW RNA replication and translation involving formation of viral-specific proteins and the production of a virus of full value in the Acetabularia cell.

[Stimulation of mouse encephalomyocarditis virus reproduction by non-multiplying poliomyelitis virus in several transplantable tissue culture lines]. / Stimuliatsiia reproduktsii virusa éntsefalomiokardita myshei nerazmnozhaiushchimsia virusom poliomielita v nekotorykh perevivaemykh liniiakh kul'tur tkani.

Reproduction of mouse encephalomyocarditis virus (EMC) was studied in 5 continuous primate cell lines: HeLa, Fl, Detroit-6, P/7, and MIO inoculated with guanidine-dependent variant of poliomyelitis virus in the absence of guanidine. Poliomyelitis virus stimulated EMC virus reproduction in all cell lines under study. This stimulation effect was studied at length in HeLa and MIO cells. In HeLa cells, stimulation was observed at a low and moderate multiplicity of infection of EMC virus but not at a high (100 PEU/cell) multiplicity. Also, when EMC virus reproduction was stimulated, a shortening of the latent period of its multiplication cycle, an increase in the number of antigen-containing cells and the number of infectious centers were observed. In MIO cells, stimulation was found to occur both with low and high doses of EMC virus but not to be accompanied by a shortening in the latent period of EMC reproduction cycle, or any increase in the antigen-containing cells or number of infectious centers. In both cell types upon mixed infection the synthesis of virus-specific RNA's of EMC virus was enhanced. It is suggested that the stimulating effect of poliomyelitis virus is realized in HeLa and MIO cells at different stages of EMC virus reproduction.

[Detection of foci of hemorrhagic fever with renal syndrome in the Estonian SSR]. / Obnaruzhenie ochagov gemorragicheskoi likhoradki s pochechnym sindromom v Estonskoi SSR.

Examination by the enzyme-immunoassay of organs of 10 small mammal species trapped in different landscape zones of the Estonian SSR revealed the presence of HFRS virus antigen in organs of bank voles and field mice. Radioimmunoassay studies of serum specimens from donors demonstrated the presence of antibody to HFRS virus in 2.54% of those examined.

[Use of monoclonal antibodies for differentiating strains of the virus causing the hemorrhagic fever with renal syndrome]. / Primenenie monoklonal'nykh antitel dlia differentsiatsii shtammov virusa gemorragicheskoi likhoradki s pochechnym sindromom.

Using monoclonal antibody and animal immune sera the experiment confirmed the existence of antigenic relationships between the strains of virus of hemorrhagic fever with renal syndrome (HFRS) isolated in the USSR from Clethrionomys glareolus and members of all known serotypes of HFRS virus. Clear-cut differentiation was made from serotypes Apodemus and Rattus, and cross-relationships were shown between the strains isolated in the USSR and Prospect Hill virus (PHV), a member of the serotype Microtus isolated in the USA.

[Demonstration of the virus of hemorrhagic fever with renal syndrome in the organs of rodents from natural foci of the infection in the USSR and the serodiagnosis of the diseases]. / Indikatsiia virusa gemorragicheskoi likhoradki s pochechnym sindromom v organakh gryzunov iz prirodnykh ochagov infektsii v SSSR i serodiagnostika zabolevanii.

An indirect fluorescent antibody test (IFAT) and an enzyme-immunological test (ELISA) were used for the detection of HFRS virus in organs of rodents from HFRS foci in the USSR. The virus was found in 115 out of 1120 bank voles, 9 out of 92 redbacked voles, and 2 field voles examined. Spontaneous infection-rate of bank voles in population varied from 1.3 to 100% correlating with the epidemiological situation in foci. IFAT and ELISA were successfully used for serodiagnosis of HFRS. Examinations of 335 paired sera from 157 patients by the IFAT demonstrated seroconversion. Retrospective diagnosis and diagnosis of subclinical forms of the disease were also made.

[Spontaneous hepatitis in the crab-eating macaque exposed to immunodepressants]. / Spontannyi gepatit u iavanskoi makaki, podvergnutoi vozdeistviiu immunodepressantov.

A case of spontaneous hepatitis was detected in experiments aimed at working out the conditions for reproduction of the immunosuppressed state in Macaca fascicularis with the purpose of subsequent infection of these monkeys with non A non B hepatitis virus transmitted by the fecal-oral route. One of 6 monkeys at the 8th day of the experiment was found to have developed an increase in the level of serum aminotransferases which grew progressively reaching high values by day 14. Fecal specimens from this monkey collected on the 5th day and later contained spherical virus-like structures 27 nm in diameter, antigenically identical with hepatitis A (HAV) virus. In the other 5 monkeys, no similar structures were found in fecal specimens throughout the experiment. The monkey with the signs of hepatitis was sacrificed on the 16th day of experiment, i. e. on the 8th day from the onset of hyperenzymemia. Immune electron microscopy of extracts of hepatic tissue and fecal specimens collected from this monkey has revealed 27 nm particles antigenically identical with HAV. The bulk of viral particles from the liver sedimented in cesium chloride buoyant density zone of 1.32 g/cm3, and from fecal specimens in the zone of 1.36 g/cm3. In the liver of this monkey, histological changes were found which are observed in acute hepatitis, and HAV antigen in hepatocyte cytoplasm was detected by the fluorescent antibody technique. It is suggested that the spontaneous disease of this monkey was due to natural infection with HAV which could be provoked by experimental immunosuppression.

[Cases of hemorrhagic fever with renal syndrome in Amur Province associated with the rat serotype of the virus]. / Zabolevaniia gemorragicheskoi likhoradki s pochechnym sindromom v Amurskoi obl., sviazannye s krysinym serotipom virusa.

To carry out serodiagnosis and to determine the serotype of the virus causing hemorrhagic fever with the renal syndrome (HFRS), paired sera obtained from 28 HFRS patients, 42 persons with a history of HFRS (1-17 years after convalescence), and 268 serum samples from healthy persons residing at the areas with the natural foci of this infection have been studied by indirect immunofluorescence techniques at the territory of the Amur Province. This study has demonstrated for the first time that, alongside the diseases caused by HFRS virus of serotype Apodemus, HFRS viruses of serotype Rattus and an unidentified serotype serve as the source of infection for the population of the Amur region. The leading role of serotype Rattus in HFRS has been confirmed by the detection of antibodies mainly to this serotype in serum samples taken from convalescents after HFRS and from the healthy population of the areas with the foci of HFRS virus infection.

[Hantavirus infection in bank voles in the natural reservoir. Part 1. Characteristics of an infection process in bank voles]. / Khantavirusnaia infektsiia u ryzhikh polevok v prirodnom ochage. Soobshchenie 1. Osobennosti infektsionnogo protsessa v organizme polevok.

The specific features of hantavirus infection in naturally infected bank voles (Clethrionomys glareolus), the principal host of hantavirus of the serotype Puumala, were studied during long-term observation of individually marked animals in the active focus of hemorrhagic fever with renal syndrome (HFRS) in the south of Udmurtia. The infection time in the bank voles was defined by paired serum seroconversion tests. In the natural focus, hantavirus was shown to cause asymptomatic persistent infection in the bank voles with the body's peak accumulation of the virus and its environmental discharge within the first month of infection. In this period the animals present the greatest epidemic and epizootic hazards. Hantavirus infection has no negative impact on the viability of bank voles.