RESUMO
According to modern classification, tick-borne flaviviruses have been divided into a mammalian tick-borne virus group and a seabird tick-borne virus group (STBVG). The STBVG includes the Tyuleniy virus, Meaban virus, Saumarez Reef virus, and the recently discovered Kama virus (KAMV). The latter was isolated from Ixodes lividus, an obligate parasitic tick of the sand martin (Riparia riparia), in 1989 in the central part of the Russian Plain. In 2014, based on molecular genetic analysis, it was shown that KAMV is a new virus belonging to STBVG, genus Flavivirus, fam. Flaviviridae. Very little is known about the Kama virus concerning its range, vectors, and reservoir hosts. GenBank contains a single sequence of the complete genome of this virus. In the present study, the complete genome sequences of two strains, isolated in 1983 in the Omsk region (Western Siberia) from gamasid mites in the nests of rooks (Corvus frugilegus), have been determined. Phylogenetic analyses of their genomes showed a close relationship both with each other (approx. 98.9% nucleotide identity) and with KAMV isolated in European Russia (approx. 98.4% nucleotide identity). The ecological features of KAMV that are due to the species of the vector (gamasid mites) and its hosts (colonial birds of the mainland of Eurasia) indicate that KAMV is an atypical representative STBVG.
Assuntos
Vírus da Encefalite Transmitidos por Carrapatos/genética , Infecções por Flavivirus/genética , Flavivirus/genética , Genoma Viral/genética , Animais , Antígenos Virais/genética , Aves , Vírus da Encefalite Transmitidos por Carrapatos/patogenicidade , Flavivirus/patogenicidade , Infecções por Flavivirus/patologia , Infecções por Flavivirus/virologia , Humanos , Ixodes/genética , Ixodes/virologia , Conformação de Ácido NucleicoRESUMO
Omsk hemorrhagic fever virus (OHFV) is the etiological agent of Omsk hemorrhagic fever, a disease described in the 1940s in Western Siberia. However, until now, it has been represented in GenBank by just four complete genome sequences, which do not reflect the real genetic diversity of the virus in nature. In this study, we analyzed the molecular variability and genetic structure of OHFV based on 20 complete genome sequences, fifteen of which were obtained for the first time. All these sequences belong to virus strains isolated at different times from three regions of Western Siberia. The results suggest that the genetic diversity of OHFV is significantly wider than previously thought and is represented by at least three subtypes, rather than two. This broadens our understanding of the evolutionary history of OHFV. Also, it is argued that the OHFV reference strain Bogoluvovska (NC_005062) is actually a Kubrin strain and that either cross-contamination or a laboratory error was the cause of this.
Assuntos
Vírus da Encefalite Transmitidos por Carrapatos/genética , Variação Genética , Genoma Viral , Filogenia , Sibéria , Sequenciamento Completo do GenomaRESUMO
Three basic genotypes of the tick-borne encephalitis virus have wide geographical spread; several strains have local spread. In this work, we studied the strategy of the synonymous codon usage in basic genotypes by means of calculation of relative synonymous codon usage values for each complete encoding sequences of viruses. Then, these values were analyzed by methods of the discriminant analysis. In the result of this work the conclusion about the available distinctions in the strategy of synonymous codon usage of various genotypes tick-borne encephalitis viruses was made.
Assuntos
Códon , Vírus da Encefalite Transmitidos por Carrapatos/genética , Regulação Viral da Expressão Gênica , Genoma Viral , Mutação Silenciosa , Análise Discriminante , Vírus da Encefalite Transmitidos por Carrapatos/classificação , Evolução Molecular , Código Genético , Genótipo , FilogeniaRESUMO
The prevalence of Kemerovo virus in ixodid ticks collected in 2008-2012 from 11 regions of the Russian Federation was investigated by real-time reverse-transcription PCR (RT-PCR). The presence of Kemerovo virus in Ixodes persulcatus, Ixodes ricinus, and Dermacentor reticulatus was confirmed. Virus prevalence depended on the region and varied from zero to 10.1%.
Assuntos
Vetores Aracnídeos/virologia , Ixodidae/virologia , Orbivirus/isolamento & purificação , Animais , Sequência de Bases , Dados de Sequência Molecular , Orbivirus/classificação , Orbivirus/genética , Filogenia , Federação RussaRESUMO
The main aspects of epidemiology and epizootology of the Omsk hemorrhagic fever (OHF) are analyzed. The discovery of the virus OHF in 1947, as well as the first outbreak of new diseases in the districts of the Omsk region, is described. Comprehensive work for decryption of the etiology of the OHF by specialists from the Omsk and Moscow Institutes is carried out. Long-term dynamics of activity of natural foci of OHF contains four periods of variable intensity of epidemic and epizootic processes. The main reservoir of the virus OHF in natural foci and the source of human infection is muskrat. Metaxenosis provides maintaining of the population of the virus, which is of some significance for hosts. Independent position of the virus OHF in the group of the Flaviviruses of mammals transmitted by ticks is established. There are two aenovariants of the virus OHF.
Assuntos
Vetores Aracnídeos , Vírus da Encefalite Transmitidos por Carrapatos/genética , Infecção Focal , Febre Hemorrágica de Omsk/epidemiologia , Carrapatos/virologia , Animais , Arvicolinae/virologia , Reservatórios de Doenças , Vírus da Encefalite Transmitidos por Carrapatos/classificação , Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Genótipo , Febre Hemorrágica de Omsk/transmissão , Febre Hemorrágica de Omsk/virologia , Humanos , Filogenia , Estudos Retrospectivos , Sibéria/epidemiologia , Proteínas do Envelope Viral/genética , Proteínas não Estruturais Virais/genéticaRESUMO
Haemorrhagic fever with renal syndrome (HFRS) is the most prevalent zoonotic disease in Russia. It is caused by several hantavirus species hosted by small rodents. We describe spatial and temporal patterns of HFRS incidence in the Russian Federation, and the geographic distribution of prevalent hantavirus species: Puumala (PUUV) and Dobrava (DOBV). Partial sequencing of nucleocapsid and glycoprotein genes of 117 PUUV strains and 78 DOBV strains revealed several distinct genetic subgroups. The RNA of Volga PUUV subgroup was detected in patients with HFRS and bank voles Myodes glareolus in the Volga Federal District, where the highest HFRS incidence rate has been registered yearly. The RNA of Siberian PUUV subgroup was found in M. glareolus in the trans-Ural Tyumen and Omsk Provinces, where human HFRS cases have been rare. During an HFRS outbreak in 2007 in the Central Federal District, when more than 1000 patients were affected, specific subgroups of DOBV were discovered in patients and rodents, mainly in the striped field mouse Apodemus agrarius. DOBV strains might have 89% of nucleotide difference although they were collected at places separated by 30100 km. The RNA of a unique DOBV subgroup was discovered in the southern semi-desert Astrakhan Province, mainly in A. agrarius and tamarisk jird Meriones tamariscinus. No human HFRS cases were diagnosed in this province. Russian PUUV and DOBV strains have no close homologues among European strains. Our DOBV strains might be genetically grouped together with Central European DOBV strains isolated from A. agrarius, but not from Apodemus flavicollis. The Volga PUUV subgroup is to some extent similar to Baltic PUUV strain, and Finnish PUUV strains resemble the strains from the Siberian PUUV subgroup. Thus, PCRbased monitoring and typing provided the opportunity to delineate and expand the area of hantaviruses in Russia and to identify their new genetic variants.
