RESUMO
The genetic diversity of the tick-borne encephalitis virus (TBEV) in the PCR-positive Taiga ticks collected in the Republic of Komi in 2010 was evaluated. The analyses of nucleotide sequences of the 5'-NCR fragments of viral genome from ticks had shown that 13 isolates of TBEV from 16 sequencing variants were represented by the highly pathogenic Far Eastern genotype of the TBEV and only 3 isolates were identified as the Siberian genotype of TBEV. The nucleotide sequences of 5'-NCR of viral genome strongly varied variable in individual ticks. Variability for the A1 element has been observed in all the tested samples, and for elements C1, B2, CS B--in more than 50%. A2 element and ATG codon of the 5'-NCR remained completely conservative. Computer simulation of conformations of the 5'-NCR of TBEV genome demonstrated the possibility of significant changes of the spatial structure of the 5'-NCR of viral genome in individual taiga ticks. The obtained data confirm the hypothesis that the variability in the 5'-NCR of TBEV genome can be crucial for efficient replication of TBEV in different hosts.
Assuntos
Vírus da Encefalite Transmitidos por Carrapatos/genética , Variação Genética , Genoma Viral/fisiologia , Ixodes/virologia , Análise de Sequência de DNA , Animais , Federação RussaRESUMO
The role of birds in the focus of tick-borne infections was studied from 2006 to 2011. The frequency index of ticks carried by ground dwelling birds is about 49.7%. The index of their abundance is 3.8. The larvae of ticks have been found on birds in 43.8% of cases. Nymphs and adult ticks have been found in 39.9 and 16.3%, respectively. It was revealed that Ixodex pavlovskyi was transferred and dominated in the urban microfoci because of its ornithophily. The markers of infectious agents have been recorded in 42 of 60 bird species under study.
Assuntos
Ixodes/patogenicidade , Larva/patogenicidade , Doenças Transmitidas por Carrapatos/epidemiologia , Doenças Transmitidas por Carrapatos/transmissão , Animais , Aves/virologia , Humanos , Ixodes/classificação , Federação Russa , Doenças Transmitidas por Carrapatos/virologia , Vírus/isolamento & purificação , Vírus/patogenicidadeRESUMO
Immunogenicity of recombinant vaccinia virus strain (VR26) expressing Venezuelan equine encephalomyelitis (VEE) virus structural protein genes was studied by oral immunization. Sera of animals immunized with VR26 contained antibodies specific to VEE virus, among which antibodies with virus-neutralizing activity were present. Evaluation of the protective efficiency of oral immunization with VR26 demonstrated a high level of animal protection from lethal doses of VEE virus. Rabbits immunized orally were highly resistant (protection index 142.9) to intranasal infection, which is of priority importance for antiVEE vaccine. Comparative analysis of the results of scarification and oral immunization with VR26 indicates that the type of immune response depends on the method of immunization. These results demonstrate good prospects of oral vaccination with recombinant VR26 strain for immunoprophylaxis of VEE.
Assuntos
Vírus da Encefalite Equina Venezuelana/genética , Genes Virais , Vaccinia virus/imunologia , Proteínas Estruturais Virais/genética , Vacinas Virais/imunologia , Administração Oral , Animais , Anticorpos Antivirais/biossíntese , Anticorpos Antivirais/imunologia , Encefalomielite Equina Venezuelana/prevenção & controle , Testes de Neutralização , Coelhos , Recombinação Genética , Vaccinia virus/genética , Vacinas Virais/administração & dosagemRESUMO
Venezuelan equine encephalomyelitis (VEE) virus-based vectors for expression of heterologous genes have been constructed using full-length cDNA copy of the interstrain recombinant virus (Trinidad Donkey and 230 strain). Gene cassettes carrying the subgenomic mRNA promoter of VEE virus and the preS2-S gene of hepatitis B virus (HBV) were inserted before or after the genes of structural viral proteins. Live virus stocks were obtained by transfection of chick embryo fibroblasts with in vitro transcribed full-length RNA. Insertions of gene cassettes before the structural region resulted in expression of HBsAg (VEHB-25 and VEHB-361 viruses), whereas insertions in the 3' region did not. Recombinant virus VEHB-25 expressed HBsAg during 5 passages in Vero cells. VEHB-25 stimulated immune response to HBsAg and was less virulent than the parental virus.
Assuntos
Encefalomielite Equina Venezuelana/genética , Antígenos de Superfície da Hepatite B/genética , Vírus da Hepatite B/genética , Precursores de Proteínas/genética , Proteínas do Envelope Viral/genética , Animais , Linhagem Celular , Embrião de Galinha , Chlorocebus aethiops , Clonagem Molecular , Encefalomielite Equina Venezuelana/imunologia , Antígenos de Superfície da Hepatite B/ultraestrutura , Microscopia Eletrônica , Plasmídeos , Regiões Promotoras Genéticas , Precursores de Proteínas/ultraestrutura , RNA Mensageiro/genética , RNA Viral/genética , Coelhos , Recombinação Genética , Inoculações Seriadas , Células VeroRESUMO
The 10466 nucleotide long sequence of the cDNA copy of the tick-borne encephalitis strain 205 viral genome has been determined. It includes the 5'-nontranslating region, the genes for structural as well as nonstructural proteins and the first 93 nucleotides of 3'-nontranslating region. The difference in amino acid sequences of structural and nonstructural proteins of strains 205. Sofjin and Neudoerfl of the tick-borne encephalitis virus and the nucleotide changes in 5'- and 3'-nontranslating of these strains are discussed.
Assuntos
Vírus da Encefalite Transmitidos por Carrapatos/genética , Sequência de Aminoácidos , Sequência de Bases , DNA/genética , Escherichia coli/genética , Genes Bacterianos , Genes Virais , Dados de Sequência Molecular , Mapeamento por Restrição , Homologia de Sequência do Ácido NucleicoRESUMO
The complete primary structure of cDNA for hemagglutinin gene of influenza virus A/FPV/weybridge/27 subtype H7 has been determined. Its comparison with the structures of analogous genes from other strains of the same subtype has shown 75% of base changes resulting in silent mutations. This suggests the weak immunological pressing in course of evolution of this subtype strains. The reason for apathogenicity of this avian strain is supposed to be elimination of a glycosylation site present in the strain A/FPV/Rostock/34. The possibility of using the obtained data for construction of the new generation of vaccines is discussed.
Assuntos
Genes Virais , Hemaglutininas Virais/genética , Vírus da Influenza A/genética , Sequência de Aminoácidos , Sequência de Bases , Dados de Sequência MolecularRESUMO
Complete nucleotide sequence of the cloned full-length DNA copy of the influenza virus A/FPV Weybridge (H7N7) neuraminidase gene has been determined.