[Specific markers for the detection of circulation of Tahyna, Inko and Batai viruses (Bunyaviridae, Bunyavirus) in humans, mosquitoes, ticks and cattle of the Ul'ianovsk region]. / Spetsificheskie markery tsirkuliatsii virusov Taginia, Inko i Batai (Bunyaviridae, Bunyavirus) sredi naseleniia, komarov, kleshchei i krupnogo rogatogo skota Ul'ianovskoi oblasti.

Comprehensive examinations of the population, sanguivorous arthropoda and domestic animals were for the first time held in the territory of the Ulyanovsk region. An active circulation of certain arboviruses was detected and a predominantly ecological relation of California encephalitis serogroup viruses with Aedes mosquitoes, on the one hand, and of Batai viruses with Anopheles mosquitoes, on the other hand, was established. The most reliable detection of antibodies to California encephalitis viral complex was pointed out.

[Isolation of Getah virus (Togaviridae, Alfavirus) strains in North- Eastern Asia]. / Izoliatsiia shtammov virusa Geta (Togaviridae, Alfavirus) v Severo- Vostochno'i Azii.

Fifteen strains of Getah alfavirus were for the first time isolated from Aedes and Culex mosquitoes in Yakutia, Magadan region, Buryatia, and Khabarovsk region of the Russian Federation and in Mongolia. The area of this virus dissemination in the above regions was steppe, mixed forest, Northern taiga, and forest-tundra zones, reaching the tundra zone in the North. Getah virus is the only alfavirus occurring under such severe climatic conditions.

Isolation of two strains of West Nile virus during an outbreak in southern Russia, 1999.

From July to September 1999, a widespread outbreak of meningoencephalitis associated with West Nile virus (Flavivirus, Flaviviridae) occurred in southern Russia, with hundreds of cases and dozens of deaths. Two strains of West Nile virus isolated from patient serum and brain-tissue samples reacted in hemagglutination-inhibition and neutralization tests with patients' convalescent-phase sera and immune ascites fluid from other strains of West Nile virus.

[Isolation of the West Nile Fever virus from human patients during an epidemic outbreak in the Volgograd and Astrakhan regions]. / Vydelenie virusa likhoradki Zapadnogo Nila ot bol'nykh liudei v periodépidemicheskoi vspyshki v Volgogradskoi i Astrakhanskoi oblastiakh.

Two strains of West Nile virus LEIV 27889 Vig and Ast 986 were isolated from the brain of a dead subject and from the blood of a patient, respectively, during an outbreak of serous meningitis and meningoencephalitis in July-September, 1999, in the Volgograd region, Krasnodar territory, and Astrakhan region. These strains reacted with convalescent sera in hemagglutination inhibition test, which proves their etiological role in this outbreak.

[Identification of California serogroup viruses (Bunyaviridae, Bunyavirus) using monoclonal antibodies to Inkoo virus]. / Identifikatsiia shtammov virusov Kaliforniiskoi serogruppy (Bunyaviridae, Bunyavirus) s ispol'zovaniem monoklonal'nykh antitel k virusu Inko.

Five types of monoclonal antibodies to inkoo virus were used to detect antigenic relationships between 12 Inkoo-like strains and the prototype Inkoo virus strain. Eight strains were found antigenically very close or identical to Inkoo virus, and the rest 4 are probably original variants (viruses) of California serogroup.

[Kama, a new virus (Flaviviridae, Flavivirus, Tiulenii antigenic group), isolated from Ixodes lividus ticks]. / Novyi virus kama (Flaviviridae, Flavivirus, antigennaia gruppa tiulenii), izolirovannyi iz kleshchei Ixodes lividus.

Three identical strains of a new virus Kama (Flaviviridae, Flavivirus, Tyuleny antigenic group) were isolated from Ixodes lividus Roch, obligate parasites of Riparia riparia L. The ticks were collected in June, 1990 in Tatarstan on the islands in the basin of the Kama river. The strains were examined under electron microscope and by serological tests (neutralization, complement fixation, hemagglutination inhibition, and indirect immunofluorescence). The virus is antigenically related but not identical to Tyuleny virus. Hence, the Tyuleny antigenic group at present includes viruses Tyuleny, Meaban, Gadgest Gally, Saumares Reef, and Kama. All these viruses are associated with an ecosystem including ixodide ticks, obligate parasites of colonial birds.

[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.

[Further study of hantavirus circulation in the Russian Federation]. / Dal'neishee izuchenie tsirkuliatsii khantavirusov v Rossiiskoi Federatsii.

Lung specimens of 1514 small mammals of 35 species captured in 1991-1995 at 9 territories of Russia were tested in ELISA for virus antigens of hemorrhagic fever with the renal syndrome (HFRS). The antigens were detected in lung specimens of Clethrionomys glareolus, Microtus arvalis, Microtus gregalis, Microtus fortis, Arvicola terrestris, Apodemus agrarius, Micromys minutus, and Sorex sp., well known as Hantavirus reservoirs, captured in the Vologda, Yaroslavl, Saratov, Astrakhan, and Chita regions. Infection of Microtus maximoviczii revealed in the Chita region was first found in China. Previously there were no reports about the circulation of hantaviruses in this region. Our study added one more host to the list of HFRS virus hosts: Meliones tamariscinus.

[Distribution of viruses from the Californian encephalitis serogroup (Bunyaviridae, Bunyavirus) in the northern expanses of Russia]. / Rasprostranenie virusov serogruppy Kaliforniiskogo éntsefalita (Bunyaviridae, Bunyavirus) v severnykh shirotakh Rossii.

The study was carried out in 1983-1991 and covered a territory of about 10 x 10(6) km2 in various physico-geographic areas (East Fennoscandia, Northern Russian Plain, West Siberia, Central Siberia, North-Eastern Siberia, and Northern Pacific Region) in the Arctic, Subarctic, Northern-Central-Southern taiga, forest-steppe, and steppe in Northern Russia. A total of 251 strains were isolated from 1391,900 mosquitoes, identified as the California group snowshoe hare (83), Inkoo (44), and Tahyna (2) viruses; 122 strains were not completely identified. Some of the strains with uncommon antigenic composition can be natural reassortants. Fifty-two percent of strains were isolated from Aedes communis and the associate species of mosquitoes, other hosts were A. excrucians (8%), A. cantans (6.25%), A. flavescens (6.25%), A. ciprius (6.25%), A. punctor (4.5%), A. vexans (4.5%), A. cataphylla (3.6%), A. nigripes (3.6%), and A. hexodontus (2.6%). The infection rate of mosquitoes was 0.009% in the tundra, 0.012% in forest-tundra, 0.01% in Northern taiga, 0.02% in Central taiga, 0.017% in Southern taiga, 0.026% in forest-steppe, and 0.097% in steppe. The epidemic season is one month in the tundra (from the beginning of July till the beginning of August), two months in Northern taiga (July-August), and three months in Central taiga (from the second half of June till the beginning of September). The highest infection rate of mosquitoes was observed at the end of the epidemic season in all regions. SSH strains prevailed to the East from the Enisei river, whereas to the West and in the Subarctic regions INK virus predominated, SSH being rare; in the taiga the distribution was quite the opposite. TAH virus was virtually absent. Human morbidity was observed in all territories studied. The immune stratum of adult population is about 30% in the tundra and forest-tundra and about 50% in Northern and Central taiga.

[Mosquito-borne arboviruses in the Baikal region]. / Peredavaemye komarami arbovirusy v pribaikal'e i zabaikal'e.

A total of 20 virus strains were isolated from arthropods and rodents in the Baikal region in 1992. Thirteen of these were California serogroup viruses, 4 Batai virus strains (Bunyaviridae, Bunyavirus), and 3 Gheta virus strains (Togaviridae, Alphavirus, Semliki complex). The rates of mosquito infection with California, Batai, and Gheta viruses were 1:6500, 1:24000, and 1:24000, respectively. The results of the neutralization test indicate the similarity of the isolated California complex strains to the mountain hare virus, the most pathogenic virus in this group.

[The characteristics of the pathogenic properties of new strains of viruses of the California encephalitis antigenic complex isolated in Arkhangelsk Province]. / Kharakteristika patogennykh svoistv novykh shtammov virusov antigennogo kompleksa kaliforniiskogo éntsefalita, izolirovannykh v Arkhangel'skoi oblasti.

Neurotropic properties of Leiv 12724 Ax and Leiv 13004 Ax strains were demonstrated by inoculation of green monkeys, Syrian hamsters and white mice using different routes. The strain Leiv 13004 Ax showed more marked pathogenicity for monkeys and rodents producing lesions in all parts of the brain: temporal, frontal, occipital, cerebellar, medulla oblongata and spinal cord where productive vasculitis, perivascular infiltrations, hemorrhages, and dystrophy of nerve cells were observed. In hamsters, the strains Leiv 13004 Ax and Leiv 12724 Ax inoculated subcutaneously produced latent infection with long-term virus carrier state.

[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.

[The circulation of viruses of the California encephalitis and Bunyamwera groups (Bunyaviridae, Bunyavirus) on the northeastern Russian plain]. / Tsirkuliatsiia virusov kompleksov Kaliforniiskogo éntsefalita i Bun'iamvera (Bunyaviridae, Bunyavirus) na severo-vostoke Russkoi ravniny.

In the Komi ASSR, 102.2 thousand mosquitoes, 207 small mammals, 1487 blood serum specimens from people, 793 cow blood sera, 140 blood serum specimens from reindeer were collected in June-August, 1988. Twenty seven virus strains isolated from mosquitoes were classified into Bunyaviridae family according to the data of electron microscopic studies. Identification of the isolates by CFT and IFA showed 18 of the strains to belong to California encephalitis complex and 9 to Bunyamwera complex. Serological studies by neutralization test demonstrates a high frequency of contact of the human population and domestic animals with viruses of the California complex practically in the entire study area: an average of 45% among human subjects, 48% among cattle and 33% among reindeer. Such high values of the immune portions indicate the activity of the discovered natural foci of this complex. The results for Batai virus from the Bunyamwera complex do not indicate its high activity: approximately 2% of positive findings in human subjects and about 4% in the cattle. The results permit a prognosis of California encephalitis and Bunyamwera complex viruses spread in the northern part of Western Siberia.

[A comparative analysis of the polypeptides of the the Sindbis and Karelian fever viruses]. / Sravnitel'nyi analiz polipeptidov virusov Sindbis i karel'skoi likhoradki.

In pulse-chase experiments with Karelian fever virus-infected cells, proteins were found with molecular weights of 130, 98, 78, and 62 kD of which the first, second and fourth were classified as polypeptide precursors of the structural proteins of virion. The molecular weights of proteins E1, E2 and C of 52, 47 and 34 kD, respectively, as well as isoelectric points of isolated glycoproteins (pI E1 = 6.3, pI E2 = 8.4) were similar in KFV (strain Leiv-9298) and Sindbis virus (strain AR339). The antigenic similarity of the strains under study in neutralization test with hyperimmune sera, the identity of physicochemical characteristics of the structural proteins of KFV and prototype Sindbis virus strain suggest a close relationship of the Leiv-9298 strain to the Afro-European variants of Sindbis virus.

[Monoclonal antibodies to the Karelian fever virus. The characteristics of their biological properties]. / Monoklonal'nye antitela k virusu karel'skoi likhoradki. Kharakteristika biologicheskikh svoistv.

Biological properties of 6 variants of monoclonal antibodies (MAb) to Karelian fever virus, a member of the alpha-virus serocomplex Sindbis-WEE, produced by the available hybridomas. The productivity of hybridomas of the "Karel" series in tissue culture and in cultivation as ascitic fluid was evaluated. Among the antibodies analysed, all were specific to envelope proteins, of them 2 were against protein E2 and four against protein E1. Comparison of MCA biologic activity (neutralizing, antihemagglutinating activities, participation in immunofluorescence, EIA, and immune blotting) allows one to distinguish four different hybridomas among them producing specific antibodies differing in their properties.

[The isolation of tick-borne encephalitis virus strains and the determination of the scope of immune stratification among the population and the domestic animals on the northern Russian plain]. / Izoliatsiia shtammov virusa kleshchevogo éntsefalita i opredelenie velichiny immunnoi prosloiki sredi naseleniia i domashnykh zhivotnykh na severe Russkoi ravniny.

Between 1986 and 1987 the authors conducted virological survey of 689 Ixodes persulcatus and 420 mouse-like and insectivorous rodents at the territory of Arkhangelsk Province and the Republic of Komi. A total of 8 strains of tick-borne encephalitis virus were isolated. Out of them 3 strains were isolated from small mammalians (2 from Clethrionomys glareolus, 1 from Microtus oeconomus) at the southeastern areas of Arkhangelsk Province within the middle taiga subarea, 5 strains were isolated from I. persulcatus (the rate of infection was 1.25 per cent) gathered in the southeastern Komi within the southern margins of the middle taiga subarea. PHAT investigation of the sera (2064 human, 656 cow and 171 dear specimens) evidenced almost the absence of immunity among the studied populations of the tundra and forest tundra zones. Certain positive samples observed in the northern taiga region could be explained by the infection gained in areas situated more to the south. Among the middle taiga human populations the immunity reached 4.9 per cent.

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.