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Biomedical subjects

V I Zlobin

Publications and source records attributed to V I Zlobin.

At least 19 recordsLinked to original sources
PubMed2004

Tick-borne virus diseases of human interest in Europe.

Several human diseases in Europe are caused by viruses transmitted by tick bite. These viruses belong to the genus Flavivirus, and include tick-borne encephalitis virus, Omsk haemorrhagic fever virus, louping ill virus, Powassan virus, Nairovirus (Crimean-Congo haemorrhagic fever virus) and Coltivirus (Eyach virus). All of these viruses cause more or less severe neurological diseases, and some are also responsible for haemorrhagic fever. The epidemiology, clinical picture and methods for diagnosis are detailed in this review. Most of these viral pathogens are classified as Biosafety Level 3 or 4 agents, and therefore some of them have been classified in Categories A-C of potential bioterrorism agents by the Centers for Disease Control and Prevention. Their ability to cause severe disease in man means that these viruses, as well as any clinical samples suspected of containing them, must be handled with specific and stringent precautions.

Animals↗
PubMed1996

[Infectious morbidity in technogenic environmental pollution].

Technogenic environmental pollution has a marked indirect influence on the growth of infection morbidity. While comparing areas with different technogenic loads, the most significant differences in the levels of morbidity were noted in the period of minimal epidemic process intensity. This period was the most susceptible link of an epidemiological year.

Environmental Pollution↗
PubMed1995

Antibodies against tick-borne encephalitis virus (TBEV) non-structural and structural proteins in human sera and spinal fluid.

Western immunoblotting of the serum and spinal fluid of patients with tick-borne encephalitis (TBE) revealed the presence of antibodies against non-structural and internal virion proteins. Antibodies against different viral proteins have been shown to appear 8 days postinfection and to circulate for more than 2 months in case of acute TBE. Antibodies against structural glycoprotein E and non-structural glycoprotein NS1 do not prevail over antibodies against other kinds of viral proteins. The large viral non-structural proteins NS5 and NS3 and small hydrophobic proteins NS2A and NS4B can cause an effective immune response as well. There is no strong correlation between immune response spectrum and fever or meningitis forms of disease. However, sera of patients with chronic TBE contained IgM antibodies to virus-specific proteins more than 1 year later and IgG antibodies with very low titers (if any).

Adolescent↗
PubMed1990

Differentiation of strains of tick-borne encephalitis virus by means of RNA-DNA hybridization.

Cloned cDNA and synthetic deoxyoligonucleotides, complementary to various parts of the genomic RNA of tick-borne encephalitis virus (TBEV), strain Sofjin, were used to distinguish between strains of TBEV and other flaviviruses. The cDNA probe hybridized with strains of TBEV and related flaviviruses of the TBE complex except for Powassan virus, and it did not react with flaviviruses of the Japanese encephalitis and dengue subgroups. Viruses of the TBE complex and some strains of TBEV were differentiated from TBEV strain Sofjin by the thermal stability of RNA-DNA hybrids. Negishi and louping-ill viruses were the most closely related to TBEV strain Sofjin, among viruses of the TBE complex. Eight strains of TBEV isolated in different geographical areas from different sources were tested by dot-hybridization with 11 deoxyoligonucleotide probes. The probes revealed genetic variations among strains of TBEV. The pattern of hybridization correlated with the source of virus strains: TBEV strains isolated from TBE patients reacted with more probes than strains isolated from ticks. Within a group of epidemic strains of TBEV there was a correlation between the geographical area of isolation and similarity to TBEV strain Sofjin.

Amino Acid Sequence↗
PubMed1985

[Use of an immunofluorescence micromethod for determining the antigens of the influenza and tick-borne encephalitis viruses].

The diagnostic possibilities of several variants of the solid-phase immunofluorescent micromethod (requiring 100-200 microliter of the reaction mixture), intended for the determination of influenza virus and tick-borne encephalitis virus antigens in material obtained from patients and ticks, have been studied. A high degree of correlation between the results obtained by the methods under investigation and the control methods has been established.

Animals↗
PubMedDate not supplied

[Analysis of genetic variability of strains of tick-borne encephalitis virus by primary structure of a fragment of the membrane protein E gene].

Primary structures of gene fragments of E protein (160 n.b.) have been determined for 29 tick-borne encephalitis (TBE) strains isolated from different parts of a territory. Analysis of homology of nucleotide sequences of these strains and data on 6 TBE strains published by other authors showed that they can be divided into 6 groups (genotypes) by the following gene typing criteria: strain structure within the genotypes differing by no more than 9%, differences between strains of different genotypes are at least 12%. Based on these criteria, the prototype strains of the Far Eastern antigenic variant (Sofyin), Central European antigenic variant (Neudoerfle), and Vergina strain form different genotypes 1, 2, and 6, respectively. East Siberian strain Aina and Ural Siberian strain Lesopark-II belong to the same TBE virus genotype 3; two-thirds of analyzed strains belong to this genotype. Genotype 4 is represented by one strain 178-79, and genotype 5 by strain 886-84, both isolated in East Siberia.

Base Sequence↗
PubMedDate not supplied

[Genetic typing of tick-borne encephalitis virus based on an analysis of the levels of homology of a membrane protein gene fragment].

All heretofore known genomic structures of tick-borne encephalitis (TBE) virus are analyzed. The authors prove the adequacy of using short fragment of E protein gene for characterization of philogenetic relationships between TBE strains. Three main genotypes of the virus are distinguished, one corresponding to Far Eastern variant, one to West, and the third includes strains belonging to Ural Siberian and Central Siberian and Transbaikal variants. Results of genetic typing by nucleotide sequences are confirmed by analysis of amino acid sequences of E protein fragments, specific marker amino acids in definite positions being determined for each genotype.

Amino Acid Sequence↗
PubMedDate not supplied

[Specific determination of flaviviruses by molecular hybridization with synthetic deoxyoligonucleotide probes].

Molecular probes were designed for the purpose of specific determination of flavioviruses transmitted by the ticks of tick-borne encephalitis (TBE) and Omsk hemorrhagic fever (OHV) as well as by mosquitoes of Japanese encephalitis (JE), North Nile (NN), Murrey Valley encephalitis (MVE), Saint-Lois encephalitis (SLE), dengue 1-4 and of yellow fever (YF). The probes are synthetic deoxyoligonucleotides with the 18-20 long basis and complementary for the RNA fragments defined by computer analysis. The thus obtained probes, which specifically hybridize themselves with the sets of the TBE virus or of the OHV virus and do not hybridize themselves with other TBE viruses' sets. Group-specific probes for YE and dengue viruses as well as virus-specific probes, which are able to detect each of the above viruses without any cross effects, were suggested for indexing and identifying the flaviviruses transmitted by mosquitoes.

Encephalitis Viruses, Tick-Borne↗
PubMedDate not supplied

[The specific reactivity of cDNA and deoxyoligonucleotide probes, complementary to the tick-borne encephalitis virus genome, with the RNA of strains of different geographical origins].

Hybridization experiments with RNA of 143 tick-borne encephalitis (TBE) virus strains isolated in different parts of the distribution area were used to study the reactivity of kDNA- and a set of 10 synthetic deoxyoligonucleotide probes. The kDNA probe under certain conditions was shown to hybridize with RNA of all the strains under study, and under other (strict) hybridization conditions did so selectively with a small number of strains. The capacity of oligonucleotide probes for hybridization with RNA of TBE virus strains varied from 12% to 100%. The differences in the hybridization activity of kDNA- and oligonucleotide probes complementary to the genomes of the Sophyin strain (Far-Eastern subtype) and Neudorffle strain (Western subtype) with TBE virus strains were used for differentiation of the strains into six genetic variants. Comparison of the reactivity of molecular probes in experiments with RNA of TBE virus strains and viruses of the TBE complex showed that the differences of the strains belonging to different genetic variants from the prototype Sophyin strain were comparable to those of some members of the TBE complex, with the exception of Powassan virus. These data attest to the necessity of further studies dealing with specification of the taxonomy of TBE complex viruses.

Animals↗
PubMedDate not supplied

[The geographical distribution of genetic variants of the tick-borne encephalitis virus].

Geographic distribution of 185 tick-borne encephalitis (TBE) virus strains isolated in 8 physico-geographic areas and classified into six genetic variants was analysed. The strains of genetic variant I homologous to the Sophyin prototype strain were found to occur predominantly in the Far East and also frequently found in Western and North-Western parts of the East European plain. The vast territories from lake Baikal in the East to Ukraine in the West harbor mostly the strains significantly different from the Far-Eastern Sophyin strain. Hybridization experiments with oligonucleotide probes specific for the Neudorffle strain showed that the strains genetically similar to the virus of central European encephalitis occurred also in Eastern Europe and Western Siberia. It is concluded that a relationship exists between genetic types of TBE virus and their geographic origin.

Animals↗
PubMedDate not supplied

[Ecology and evolution of influenza viruses in Russia (1979-2002)].

The research results on ecology and evolution of influenza A viruses, which has been conducted by the Center of Ecology and Evolution of influenza Viruses of Ivanovsky's Institute of Virology, Russian Academy of Medical Sciences, for more than 30 years, are summarized in the paper. A gene pool of influenza A viruses circulating in Russia's territory was defined. Foci of influenza A viruses were detected in natural biocenosis. Issues conditioned by the population interrelations of influenza viruses, i.e. between the populations of wild and home animals and the populations of people, are also under discussion.

Animals↗
PubMedDate not supplied

[Tick-borne encephalitis in the Russian Federation: state-of-the-art and prevention policy].

The last quarter of the 20th century in the Russian Federation was marked by an unprecedented increase in the incidence of tick-borne encephalitis (TBE) with its peaks in 1996 and 1999 when as high as 10,000 cases of the disease were notified. Its highest incidence was recorded in the Regions of the Urals and Siberia. As many as 70-80% of the persons who felt ill were urban dwellers who had been infected mainly in the anthropurgic foci occurring in abundance in the environs of cities and towns. It was found that the area of TBE had been expanded and virus-infected ticks had actively penetrated into the urban parks and small public gardens. There were as many as 70 TBE-endemic regions. As of now, it has been ascertained that TBE foci are generally combined with other infections transmitted by Ixodes ticks and caused by viruses, bacteria, rickettsia and protozoa. This result is the occurrence of mixed infections, which requires new approaches to their diagnosis, treatment, and prevention. The prevention of TBE is conventionally based on vaccination of high-risk groups comprising mainly "forest" occupations. Under the present conditions, the strategy of TBE control should be radically revised towards mass vaccination of the population living in the highly endemic areas, which will drastically reduced morbidity in the country.

Animals↗
PubMedDate not supplied

[The typing of tick-borne encephalitis virus strains by the soluble antigen].

Sucrose-acetone-treated antigens (SAA) and soluble antigens (SA) prepared from them by treatment with 8 M urea for eight TBE virus strains isolated in different parts of the virus distribution area were studied in cross CFT with immune ascitic fluids (IAF) for these strains as well as for OHF and Powassan viruses. With SAA, the difference in titres with homologous and heterologous IAFs, as a rule, did not exceed twofold, whereas with SA was 32-fold. It was also noted that in the homologous system the titre of SA decreased not more than 4-fold as compared with that of the initial SAA while in the heterologous system it declined from 4- to 16-fold or more. The level of antigenic relationship of strains was expressed by the formula HAg = SA titre/SA titre X 100%. It was shown that at HAg greater than or equal to 25% the strains used for antigen and antibody generation were closely related and at HAg less than or equal to 6.25% belonged to different subtypes. The analysis of the data suggested the existence of a fourth, "Urals-Siberian" antigenic variant of TBE virus. Using the developed criteria, the 20 strains under study (with one exception) were alloted into one of the four antigenic variants or qualified as intermediate.

Animals↗
PubMedDate not supplied

[The differentiation of viruses of the tick-borne encephalitis complex by means of RNA-DNA hybridization].

Nucleic acid spot hybridization with cloned cDNA of tick-borne encephalitis (TBE) virus, strain Sofjin, was used to differentiate strains of TBE and other flaviviruses. The cDNA probe reacted with strains of TBE and flaviviruses of TBE subgroup with the exception of Powassan virus. The probe did not react with viruses of Japanese encephalitis and Gendue subgroups. The viruses of TBE subgroup and some strains of TBE virus were differentiated from TBE strain Sofjin by thermal stability of RNA-DNA hybrids. Negishi and Louping ill viruses were found to be most closely related to TBE strain Sofjin among viruses of the TBE subgroup.

Animals↗