[A comparative experimental study of pathogenic properties of new strains of California encephalitis virus serogroups]. / Sravnitel'noe izuchenie patogennykh svoistv novykh shtammov virusa serogruppy Kaliforniiskogo éntsefalita véksperimente.

Experiments in noninbred mice, Syrian hamsters and grey monkeys were made to characterize the pathogenic properties of new strain of the California encephalitis serogroup isolated for the first time on the island of Taimir, in the Murmansk, Leningrad, Tver regions and in Karelia. All the strains displayed marked tropism for the CNS. The strains isolated in the northern regions of this country turned out more pathogenic for the animals. The strain Leiv-12812 Kl (isolated in the Tver region) differed from the remaining ones in more pronounced pathogenicity for the monkeys, as well as in the site and intensity of brain lesions. The persistence of the virus in hamsters organs may play a role of a reservoir of infection in nature.

[An experimental infection caused by the Issyk-Kul arbovirus]. / Eksperimental'naia infekstiia, vyzvannaia arbovirusom Issyk-Kul'.

Pathogenic properties of Issyk-Kul virus have been experimentally studied in green monkeys, golden hamsters and white mice. The virus was identified in the blood and organs of all the animals. Pathohistological studies have revealed inflammatory and dystrophic changes in the central nervous system, lungs, liver and kidneys. Pronounced immunomorphological changes have been observed in the spleen. The virus possessed pantropic properties and caused generalized infection in all the animals irrespective of the mode of infection. In monkeys asymptomatic infection was accompanied by marked organ damages and virusemia. The presence of specific antibodies in the blood indicated a low efficacy of humoral immunity in this infection.

[Experimental infection caused by Issyk-Kul' arbovirus]. / Eksperimental'naia infektsiia, vyzvannaia arbovirusom Issyk-Kul'.

Experimentally in green monkeys, Syrian hamsters and white mice the authors studied the pathogenic properties of a new virus Issyk-Kul. The virus was determined in all animals--in blood and organs (brain, lungs, liver, spleen, kidneys). During the histological investigation the inflammatory and dystrophic injuries were established: in CNS, lungs, liver and kidneys. There was a distinct immunomorphological reaction in the spleen. The virus has pantropic properties and causes a generalized infection in animals.

Biological profile of a virus belonging to California encephalitis complex isolated in Karelian Autonomous Soviet Socialist Republic.

We investigated in white mice and in Syrian hamsters the pathogenesis of infection with a virus belonging to the California encephalitis complex isolated in the Karelian Autonomous Soviet Socialist Republic. The pathogenic properties of the virus were investigated also in green monkeys. The localization and character of lesions in the organs of given animals appeared to be similar. The virus appeared to possess neurotropic activity, it propagated in the animal body by haematogenous route. The virus was found to be heat-resistant and pH-sensitive.

[Biological properties of the Tahyna virus isolated in the Arctic]. / Nekotorye biologicheskie svoistva virusa Tiaginia, vydelennogo v Zapoliar'e.

The results are presented of comparative studies over the course of experimental Tahyna infection of viremia in the blood and organs, localization and patterns of lesions in the same organs after different routes of inoculation of white mice and hamsters with a new strain LEIV 9843 Mur of Tahyna virus. The results of these experiments are compared with similar studies in monkeys with asymptomatic infection, including humoral antibody detection. The pattern of lesions in the organs of animals infected with Tahyna virus (LEIV 9843 Mur strain), the mode of virus spread, tissue tropism of the virus were established. The virus thermostability and sensitivity to different pH values of the medium were determined.

[Typing of ornithosis strains with species-specific antigens]. / Tipirovanie shtammov ornitoza s pomoshci pomoshch'iu vidospetsificheskikh antigenov.

Species-specific antigens of three ornithosis strains of varying origin were isolated. These antigens were used in the complement-fixation test to study immune sera to different strains. The ornithosis strains studied were represented by three serotypes. To differentiate ornithosis from other chlamidia infections and for the preparation of diagnostic immune sera it is recommended to use species-specific antigens of serotype 3, while for vaccine production the corresponding strains should be used.

[Detection of humoral antibodies to species-specific and group ornithosis antigens in the dynamics of the infection]. / Obnaruzhenie gumoral'nykh antitel k vidospetsificheskomu i gruppovomu antigenam ornitoza v dinamike infektsii.

The time course of antibody production to group- and species-specific antigens of ornithosis agent was studied by complement fixation (CFT) and hemagglutination-inhibition (HI) tests. In rabbits after a single intravenous inoculation of the ornithosis agent, antibody to the homologous species-specific antigen appeared in the peripheral blood 3--5 days after inoculation and reached maximum levels during the 1-st week, and to the group-specific antigen could be detected 3--5 days after inoculation but reached maximum titers only 3--4 weeks later. In practical serological diagnosis of ornithosis and other chlamydia infections, the group antigen is used which gives retrospective diagnosis at 10--14 days or later. The results of the study suggest that the use of CFT with the species-specific antigen will not only differentiate ornithosis from other chlamydial infections but also will permit early serological diagnosis of ornithosis.

[Participation of species specific and group specific ornithosis antigens in immune reactions]. / Uchastie vidospetsificheskogo i gruppospetsificheskogo antigenov ornitoza v reaktsiiakh immuniteta.

The immunogenic properties of the species-specific antigen localized in the elementary particle membrane and group-specific or inner antigen of the causative agent of ornithosis were studied. The species specific antigen was shown to induce the antibody neutralizing the infectious properties of the agent as well as those agglutinating elementary bodies, inhibiting hemagglutination, and complement-fixing antibody detectable in the direct and indirect complement-fixation tests. The results indicate that the antigens most clearly defining the species-specific properties of the causative agent of ornithosis are localized in the elementary particle membrane. These antigens may be used for differential diagnosis studies employing not only CFT but also other antibody tests.