[Diseases associated with viruses of the California encephalitis serogroup, in Russia]. / Zabolevaniia v Rossii, assotsiirovannye s virusami serogruppy Kaliforniiskogo éntsefalita.

Studies of 1986-1995 revealed diseases etiologically connected with California serogroup viruses (Bunyaviridae, Bunyavirus) all over the country. Highly endemic zones are the tundra, taiga, and leafy forest. The disease occurs mainly in summer, the patients are mostly young: under 30 years of age. Analysis of 183 cases confirmed by laboratory findings enabled us to distinguish the following forms: influenza-like (70.9%) with the predominant involvement of the bronchopulmonary system (bronchitis and pneumonia) and neuroinfection (20.2%) (serous meningitis and meningoencephalitis).

[Circulation of viruses of the California serocomplex (Bunyaviridae, Bunyavirus) in the central and southern parts of the Russian plain]. / Tsirkuliatsiia virusov serokompleksa kaliforniia (Bunyaviridae, Bunyavirus) v tsentral'noi i iuzhnoi chastiakh Russkoi ravniny.

Seventy strains of California group viruses were isolated in the Central and Southern territories of the Russian plain situated in the Southern taiga, mixed forest, broad-leaved forest, forest-steppe, steppe, and semiarid zones. Sixty-three of these were isolated from 873,300 mosquitoes, 4 from patients, and 3 from rodents. 57.1% of strains were isolated from Aedes communis and the associated species, 28.5% from Aedes excrucians and associated species, and rarely from other mosquito species. The mosquito infection rate was the highest in the Southern taiga zone: 0.0103%, this value decreasing towards the Southern areas. Out of 70 isolated strains 42.3% were identified as the Inkoo virus, 47.2% wer ejust referred to the California group, and only 2.8% were Tahyna and snowshoe hare viruses. The findings of serological screening of the population correlate with the results of virological studies of mosquitoes. Population morbidity is mainly caused by the Inkoo virus in the Southern taiga and mixed and broad-leaved forest, by Inkoo and Tahyna viruses in the steppe and forest-steppe zones, and by Tahyna virus in semiarid zone.

[Serodiagnosis and epidemiology of a California encephalitis group of infections in the Ryazan' region]. / Serodiagnostika i épøidemiologiia infektsii gruppy Kaliforniiskogo éntsefalita v Riazanskoi oblasti.

Blood sera of 221 healthy residents of 4 districts of Ryazan region were tested in the neutralization test (NT) with Tahyna and Inkoo viruses. The sum of positive responses in the region was 40.7% on an average, this indicating numerous contacts of the local population with these agents. Blood sera of 520 patients with acute seasonal (May-September) fevers and neuroinfections were tested for antibodies to Tahyna and Inkoo viruses in serologic tests (NT and MAC-ELISA-IgM-antibody capture method). Etiologic relationship of the diseases with Tahyna and Inkoo viruses was detected in 51 (9.8%) cases. The patients developed two types of specific immune response, primary or secondary. The best diagnostic result was attained in testing paired sera of patients in NT and MAC-ELISA. MAC-ELISA helped etiologically diagnose the disease after a single testing of a blood serum collected in the acute period of the disease. Inkoo infection was more incident in subjects aged 21 to 40 in May and July-August. The majority of cases of Tahyna infection were diagnosed in subjects aged under 20 in June and July. The incubation period was from 3 to 7 days, the morbidity was sporadic.

[Significance of viruses of antigen complex of California encephalitis in pathology]. / Znachenie virusov antigennogo kompleksa kaliforniiskogo éntsefalita v patologii.

A study was undertaken to examine 320 patients with seasonal fevers occurred in June to September. These included fever of unknown etiology, acute respiratory virus diseases, pneumonias, bronchitis, enterovirus diseases, and serous meningitis. Serological tests revealed that in 20 (6.3%) of them the viruses of the complex in California encephalitis (Tyagin's virus or antigenically related virus) contributed to the etiology of the disease. Major clinical symptoms of the disease were defined in this group of patients. The disease appeared as neuroinfections (serous meningitis), influenza-like conditions (fever, symptoms of intoxication), occasionally, infiltrative changes in the lung. Thus, the viruses of the antigen complex of California encephalitis makes an etiological contribution to infectious abnormalities.