Over the last years, an increasing rate of ixodes tick bites has been registered in the northern regions of the European Russia. In addition, the number of subjects request medical assistance due to tick bites has been dramatically increased in the Komi Republic. In addition, incidence of tick-borne encephalitis was also increased particularly starting since 2009. However, highly limited data on pathogen genetic diversity related to viral tick-borne infections in this region are currently available. Taiga ticks (Ixodespersulcatus) collected from the Komi Republic southern and central part vegetation were examined to identify and genotype tick-borne viruses. Individual ticks were used to identify by RT-PCR viral RNA coupled to tick-borne encephalitis and Kemerovo viruses. Viral genome fragment sequencing allowed to unambiguously identify these viruses. It was found that viral RNA tick-borne encephalitis was detected in 6.8±1.2% individual ticks. Moreover, tick-linked isolate genotyping based on analyzing E protein gene fragment nucleotide sequence derived from tick-borne encephalitis discovered that 35% and 65% isolates belonged to the Far Eastern and Siberian subtype, respectively. In addition, subsequent phylogenetic analysis demonstrated that at least four variants of the Siberian and Far Eastern subtypes of tick-borne encephalitis virus were detected, which were close to the viruses circulating in the Urals and Siberia. In contrast, prevalence of Kemerovo virus in taiga ticks was 0.8±0.2%. Sequencing of Kemerovo virus RNA-dependent RNA polymerase gene fragment showed around 94% homology with the remainder of the Kemerovo virus strains. Phylogenetic analysis of the Kemerovo virus genome fragments demonstrated at least two subtypes circulating in the Komi Republic. Thus, it was suggested that tick-borne encephalitis virus was introduced relatively recently from the Urals and Siberian region into the natural foci of the Komi Republic. Moreover, genetic differences found in Kemerovo virus strains presume for them a longer lasting evolution throughout the natural foci of this region. In addition, a potential role for birds and their ticks in rapid spreading of viral tick-borne infections in the Komi Republic is also discussed. Thus, the data on genetic diversity of the viral agents related to tick-born encephalitis and Kemerovo fever may be useful for improving their diagnostics, prevention and treatment in the Komi Republic.
Introduction. Yellow fever (YF) remains one of the most common natural focal infectious diseases in the world. In connection with the increasing tourist flow to countries endemic for YF, the discovery of stable populations of Aedes aegypti and Ae. albopictus which are the main vectors of the yellow fever virus (YFV), in the southern regions of Russia, and the fact that in medical institutions in our country it is possible to obtain a live attenuated vaccine against YF, but there is no way to evaluate the effectiveness of vaccination, the question arises of the development and implementation of diagnostic kits for detecting antibodies (AB) to the pathogen by enzyme immunoassay (ELISA).The aim of this study was to develop a method for detecting specific IgG antibodies to the E protein of YFV by ELISA and assessing its diagnostic characteristics.Materials and methods. A specific cDNA was synthesized by reverse transcription on an RNA template of YFV isolated on a cell culture of Aedes albopictus clone C6/36, and a fragment of the genome coding the YFV E protein was amplified and subsequently cloned into the plasmid pET160 (Thermo Fisher Scientific, USA). The resulting gene fragment was used as a DNA template to obtain a recombinant analog of the third domain of the YFV E protein in Escherichia coli cells (BL-21(DE3)). Next, the immunogenicity of the obtained antigen was evaluated and the analysis conditions were optimized.Results. The optimal conditions for the production of the obtained recombinant E protein of YFV were determined, its specificity was confirmed by immunological methods (Western blot and ELISA), sorption buffers and blocking solutions were selected, and sensitivity and specificity of detection of antibodies to YFV using the recombinant antigen were assessed.Conclusion. A method for the detection of specific IgG antibodies to the YFV E protein by ELISA was developed. This diagnostic kit can be used both to study the protective properties of the YF vaccine and to detect imported cases of infection in non-endemic areas.
Introduction. Ixodes ticks are vectors for pathogens of many infectious diseases. Recently, during the study of Rhipicephalus geigyi ticks collected from livestock in the Republic of Guinea, a new multicomponent flavi-like RNA virus, called Kindia tick virus (KITV), was discovered with an unusual mechanism for the implementation of genetic information. The aim of the work is to detect and study the genetic diversity of KITV in ixodes ticks collected in the territory of the Kindia province of the Republic of Guinea. Material and methods. In 2021, 324 specimens of ticks of the species Amblyomma variegatum, Rh. geigyi, Rh. annulatus, Rh. decoloratus, Rh. senegalensis were collected from cattle. The detection of viral RNA was carried out in individual samples of ticks by RT-PCR, followed by the determination of the nucleotide sequence and phylogenetic analysis. Results and discussion. KITV detection rates in ticks of the species Rh. geigyi was 12.2%, Rh. annulatus 4.4%, Rh. decoloratus 3.3%. However, the KITV genetic material has not been identified in Am. variegatum ticks, which are one of the dominant species in West Africa. For all virus isolates, a partial nucleotide sequences of each of the four viral segments (GenBank, OK345271OK345306) were determined. The phylogenetic analysis showed a high level of identity (98.599.8%) for each of the four segments of the viral genome with those previously found in the Republic of Guinea. The obtained KITV isolates are most genetically close to Mogiana tick virus, which was previously detected in South America in Rh. microplus ticks and significantly differed from other multicomponent viruses circulating in Europe and Asia, including the Russian Federation. Conclusion. KITV genetic material was found in three species of ixodid ticks collected from livestock in a number of prefectures of the Republic of Guinea. The infection rate in ticks was 3.312.2%. The continuation of research in this direction remains relevant.
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