[Isolation of strains of Negishi virus in Khabarovsk Territory]. / Vydelenie shtammov virusa Negishi v Khabarovskom krae.

Two virus strains isolated from Aedes vexans nipponi and Aedes vexans vexans in 1976 and 1978, respectively, in Khabarovsk Territory were identified as Negishi virus. Among 176 human sera, 22.7% were found to contain complement-fixing antibodies to Negishi virus soluble antigen.

Differentiation in the complement fixation test of the viruses of tick-borne encephalitis complex by means of a type-specific soluble antigen.

Highly type-specific soluble antigens (SA) of viruses of the tick-borne encephalitis (TBE) complex were obtained by treatment of the sucrose-acetone antigens with 8 mol/l urea. Each SA reacted with the homologous serum only. The serum to SA of strain Sofyin and of Omsk haemorrhagic fever virus distinguished the TBE complex representatives; the difference between homologous serum titres was in the range of 4-5 two-fold dilution steps.

[Susceptibility of laboratory animals to the Chandipura and Isfahan viruses]. / Vospriimchivost' laboratornykh zhivotnykh k virusam Chandipura i Isfagan.

Pathogenicity and immunogenicity of Chandipura and Isfahan rhabdoviruses for laboratory animals were studied. Both viruses were found to be highly pathogenic for mice by the intracerebral route. Chandipura virus is highly pathogenic for mice of different ages by various routes of inoculation. The surviving animals were found to have antibodies demonstrable in different serological tests (agar gel diffusion and precipitation, complement-fixation, the neutralization test by plaque reduction in chick embryo cell culture). In the animals surviving the infection with Chandipura virus antibody could be found as early as 2 weeks, but after inoculation with Isfahan virus the antibody developed slowly and could be detected only at 4 weeks. Pathogenicity for mice of the T-227 and the prototype Isfahan virus strains differed slightly.

Radial haemolysis in gel used in serological studies on Venezuelan equine encephalomyelitis virus.

Radial haemolysis in gel was successfully used for the detection of antibody in convalescents after laboratory infection with Venezuelan equine encephalomyelitis (VEE) virus at remote intervals after infection (up to 23 years). The antibodies reacted only with VEE antigen but not with Sindbis and Chikungunya alphavirus antigens. Radial haemolysis in gel was sensitive as the haemagglutination inhibition test but the antibody could be titrated by the diameter of the haemolysis zone omitting the serum dilutions. Slight deviations in the virus dose used for sensitization of erythrocytes or in pH values were not critical. For the test, the sera were heated at 56 degrees C for 30 min. Both sera stored for long periods and those collected on paper disks could be used.

[Isolation of the Isfahan virus in Turkmenia]. / Vydelenie virusa Isfagan v Turkmenii.

This is a first report on the isolation in the USSR of Isfahan virus belonging to the Rhabdoviridae family. Two strains, T-200 and T-227, were isolated from a pool of 100 and 95 engorged Phlebotomus papatasi females collected in colonies of great gerbils in June and August, 1979, in the Kirov district, Turkmenia. According to the results of previous investigations, the human population and great gerbils in this areas were frequently found to have antibody to Isfahan virus. The strains were identified by complement fixation, indirect immunofluorescence, indirect hemagglutination tests and neutralization by the plaque reduction technique. The viruses are held by filters with pore diameter less than 100 nm, are destroyed by sodium deoxycholate, at the state of reproduction are not sensitive to 5-brom-2-deoxyuridine.

[Natural foci of viruses borne by Phlebotomus papatasi in the USSR according to a serologic study of the population]. / Prirodnye ochagi virusov, perenosimykh Phlebotomus papatasi, v SSSR po dannym serologicheskogo obsledovaniia naseleniia.

Seven hundred sixteen blood serum specimens from residents of presumable foci of phlebotomus fevers in Turkmenia, Tajikistan, Uzbekistan, Azerbaijan, and Moldavia were examined by the neutralization, complement fixation, hemagglutionation-inhibition and indirect immunofluorescence tests for the presence of antibody to viruses of the group of phlebotomus fevers (Sicilyan, Neapolitan, and Karimabad) and to rhabdovirus isfahan transmitted by phlebotomus papatasi. For the first time, antibody to Karimabad and Isfahan viruses were found in residents of the Central Asian republics. Antibody to Sicilyan and Neapolitan fevers were found in residents of all the republics examined. Data have been obtained indicating probable pathogenicity of Isfahan virus for man.

[Characteristics of the biological properties of a Kemerovo group arbovirus isolated in Transcarpathia]. / Kharakteristika biologicheskikh svoistv arbovirusa gruppy Kemerovo, vydelennogo v Zakarpat'e.

A strain of an arbovirus named Mircha was isolated from Ixodes ricinus L. ticks (30 incompletely engorged females) collected in May, 1972 from cows pastured in a forest near the village of Mircha of the Velikobereznyansky district of the Zakarpathye region of the Ukrainian SSR. The strain was found to be pathogenic for newborn white mice and rats by the intracerebral and intraperitoneal routes and for chick embryos inoculated into the yolk sac, to replicate in chick embryo fibroblast culture producing a marked cytopathic effect to be relatively stable to ethyl ether and sodium deoxylate. On the basis of the results of serological identification (CFT) it was classified into arboviruses of the Kemerovo group, the antigenic subgroup Kemeroxo-Tribec. The factors of natural focality are described briefly, and the results of the study of virus persistence in adult white mice, rats, and guinea pigs and of its immunodepressive effect are presented.

[Determination of arbovirus group affiliation in the indirect hemagglutination reaction]. / Opredelenie gruppovoi prinadlezhnosti arbovirusov v reaktsii nepriamoi gemaggliutinatsii

A dry polyvalent erythrocyte immunoglobulin diagnostic preparation for arboviruses of Group B may be prepared to be used in the indirect hemagglutination test. The preparation detects antigens of arboviruses of this group in the tissue culture fluid and in suckling mouse brain tissue treated with sucrose-acetone. The test with Group B arbovirus antigens is inhibited specifically by the homologous polyvalent immune gamma globulin. Inhibition of hemagglutination by species-specific immune globulins to individual members of Group B arboviruses permits typing of tick-borne encephalitis birus only. In making the erythrocyte diagnostic preparation, the optimal concentration of the sensitizing immune gamma globulin should be determined experimentally.