Mikhail Yu. Kartashov

High-throughput sequencing methods have made it possible to identify numerous novel tick-borne viruses that are potentially pathogenic to humans. Among these, Songling virus (Orthonairovirus songlingense, SGLV) has been associated with febrile illness in patients following tick bites in China, but its geographic distribution outside China remains largely unexplored. In this study, we aimed to detect SGLV circulation in ticks across Asian Russia, focusing on regions bordering China. A total of 3444 adult ticks representing six species were collected from 170 locations across 11 regions during the summer of 2024. SGLV RNA was detected in Haemaphysalis concinna ticks, with 11 positive specimens yielding an SGLV RNA prevalence rate of 2.2%. Positive ticks were found in four regions, with the highest positivity rate (5.8%) recorded in Amur Oblast, which directly borders China. The detection of SGLV in the Republic of Altai represents the westernmost record of this virus to date. Full-length nucleoprotein-coding sequences obtained for all Russian isolates revealed up to 1.2% nucleotide divergence. Phylogenetic analysis confirmed that all Russian SGLV isolates belong to Orthonairovirus songlingense, with the Altai SGLV isolate showing genetic similarity to a human-derived Chinese SGLV isolate. Co-infections with Rickettsia heilongjiangensis were detected in four SGLV-positive ticks, highlighting the potential for simultaneous pathogen transmission. These findings establish the first evidence of SGLV circulation in Russia across a wide geographic range and underscore the need for differential diagnosis of febrile illnesses following tick bites in this region.

Introduction. Despite successes in hepatitis B virus (HBV) molecular virology, prevention, and treatment, HBV infection remains relevant. The study aimed to analyze serological and molecular genetic markers among older individuals in Novosibirsk, and characterize identified HBV variants. Materials and methods. The study included 630 conditionally healthy individuals undergoing routine medical examination. Serological markers (HBsAg, AntiHBs, AntiHBc, HBeAg, AntiHBe) were determined by ELISA, and HBV DNA — by real-time PCR. Full-length genomic sequences of identified HBV isolates were obtained using next-generation sequencing (NGS). Results. HBV genetic material was detected in 6 patients, and their full genome sequences were obtained. The genotype and subgenotype of identified HBV variants were determined, and clinically significant mutations were analyzed. Only 29% of patients had protective antiHBs levels ( 10 IU/mL), with 38% also having antiHBc antibodies. Low-titer protective antibodies (10–100 IU/mL) were most common in both АntiНВs+/AntiНВс– and AntiНВs+/AntiНВс+ groups. Low titers were more frequent in the AntiНВs+/AntiНВс– group, while high titers ( 400 IU/mL) were more common in the AntiНВs+/AntiНВс+ group. Conclusions. It has been shown that among the older age groups, there is a low intensity of humoral immunity to HBV, which may indicate a widespread problem of reducing the level of protective antibodies over time post-vaccination, or insufficient vaccination coverage in this population group. A decrease in HBV antibody titer below the protective level in the elderly significantly increases the a of primary infection or reinfection with HBV in this population group. As a recommendation, the inclusion of AntiHBs serological monitoring in the medical examination program for the elderly can be considered. The data obtained also actualize the problem of booster vaccination in this age group. The total presence of mutations potentially associated with disease progression in the identified HBV variants and the widespread prevalence of mutations that can alter HBsAg antigenicity require attention to these patients.

Yellow fever virus (YFV), transmitted by Aedes aegypti mosquitoes, poses a serious threat to public health in the countries of tropical and subtropical reg

Introduction. The unfavorable epidemiological situation with viral tick-borne infections can be characterized not only by an increase in the incidence of «classical», well-known diseases, but also by the discovery of new pathogens, the role of which remains poorly understood. Yezo virus (YEZV) belongs to the group of recently discovered tick-borne nairoviruses. YEZV circulation is characteristic of Japan, China, and a number of regions in Russia (Primorsky, Khabarovsk, and Zabaykalsky Krais; Tomsk Oblast). The aim of the study was to screen and characterize the molecular genetics of YEZV isolated from ticks in the Amur region. Materials and methods. In the study, 704 individual tick samples (463 I. persulcatus ticks and 241 H. concinna ticks) collected from vegetation in 15 locations in 5 districts of the Amur Region were analyzed for the presence of YEZV RNA. Full-length genomic sequencing of the identified YEZV genetic variant was performed by preliminary enrichment of YEZV cDNA using multiplex PCR with a primer panel developed by us. Results. The YEZV infection rate in the studied sample of I. persulcatus ticks was 0.2% (1/463; 95% CI: 0.1–1.2). Conclusion. The results of this study expand our understanding of the spread of YEZV in Russia. Up-to-date information on the circulation and genetic diversity of nairoviruses that pose a potential threat to humans and animals contributes to the regulation and adjustment of preventive and anti-epidemic measures, as well as the implementation of adequate region-oriented laboratory diagnostics of IPK in the Far East, and especially in areas bordering China.

The aim of the work was to identify viruses transmitted by transmission in hard ticks collected in several regions of the European part of Russia. The viral RNA of ticks of the genus Ixodes , collected from natural foci of tick‐borne encephalitis in the Astrakhan region, Karelia and Stavropol Krai, was studied by PCR and sequencing of the obtained virus‐specific DNA fragments. Genomic markers of viruses of the Flaviviridae , Phenuiviridae and Nairoviridae families were found in ticks collected in the Astrakhan Region, Republic of Karelia and Stavropol krai. Genetic markers of viruses previously not described for Russia were found in Ixodes ticks collected in the Astrakhan Region, Republic of Karelia and Stavropol krai. Natural foci of tick‐borne infections tend to expand their range, and, therefore, research to identify new viruses ecologically associated with ixodid ticks is becoming increasingly important.

Seoul orthohantavirus is one of the causative agents of hemorrhagic fever with renal syndrome (HFRS) in the Russian Far East. Foci of SEOV in Norway rats have been identified in the cities of Vladivostok and Khabarovsk. The aim. Study of a clinical case of HFRS with a fatal outcome, from Komsomolsk-on-Amur in 2025. Materials and methods. Samples of blood serum and autopsy material (blood, lung, spleen, liver, kidney tissues) from a resident of Komsomolsk-on-Amur with a clinical diagnosis of HFRS were examined using enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR) followed by sequencing. Results. The laboratory studies confirmed the clinical diagnosis. Antibodies to hantaviruses in a titer of 1:3200 (IgM) and 1:1600 (IgG) were detected by the ELISA in the blood serum. SEOV RNA was detected in blood serum and autopsy material (blood, lung,spleen, liver, kidney tissues) studying by the RT-PCR and using the OM-Screen-GLPSRV test system. Analysis of genome fragments showed high homology of SEOV from Komsomolsk-on-Amur with virus strains previously identified in Khabarovsk, as well as those widespread in China. Genetic evidence of human infection, associated with the Seoul virus circulating in the city of Komsomolsk-on-Amur has been obtained, and two hypotheses have been put forward for the formation of the focus: importation with infected rats from China or Khabarovsk, and the possible existence of a mainland variant of the virus in a vast territory, including the eastern regions of China and Khabarovsk Krai. Conclusion. Third urban focus of Seoul hantavirus was detected in Russia. The fatal outcome of HFRS could be caused by a comorbidity: chronic alcohol intoxication with multiple organ manifestations.

A novel flavi-like virus with a segmented genome—Alongshan virus (ALSV)—has been isolated from Ixodes ticks in Russia. In this study, 4458 ixodid ticks collected in 22 regions of Russia were tested for genetic markers of ALSV by RT PCR. The highest rates of ALSV infection in ticks were detected in the Republic of Khakassia (3.3%) and in Kemerovo Oblast (2.4%), while low infection rates were more typical in the European part of Russia (0.4–0.7%). Complete four-segment genomes of 20 ALSV isolates derived from 22 PCR-positive Ixodes persulcatus ticks were sequenced using a high-throughput approach. The nucleotide sequences for Asian ALSV isolates have a 94.5–96.5% identity to ALSV isolates previously found in China, with this range for the European isolates being 89–93%. This data, together with phylogenetic analysis, indicates the existence of Asian and European subtypes of ALSV, and these may be associated with I. persulcatus and I ricinus ticks. The obtained results express the spread of ALSV in Russia and also may be useful for the diagnosis, prophylactics, and treatment of this infection.

A novel flavi–like virus such as Alongshan virus (ALSV) with segmented genomes have been early isolated from Ixodes ticks in Russia. In this study, the ALSV genetic markers were tested in 4458 ixodid ticks collected in 22 regions of European and Asian part of Russia by RT PCR. The highest infection rate of ALSV in ticks was detected for Khakassia Republic (3.3%) and Kemerovo region (2.4%) and low infection rate was more typical for European part of Russia (0.4–0.7%). The sequencing complete genomes (four segments) of the ALSV from 22 PCR positive Ixodes persulcatus ticks was carry out by high–throughput sequencing. The identity level nucleotide sequences for Asian ALSV isolates are 94.5–96.5% with ALSV isolates previously found in China and in 89–93% range for the European isolates. This data together with phylogenetic analysis are propose the existence of Asian and European subtypes of the ALSV, and they may be associated with I. persulcatus and I. ricinus ticks. The obtained results actualize spreading ALSV in Russia and also may be useful for diagnostics, prophylactic and treatment this infection.

The work is an overview of the loop-mediated isothermal amplification (LAMP) method and its application to diagnostics of hemorrhagic fevers. Its objective was to briefly characterize isothermal amplification and systematize the available data on diagnostics by this method of hemorrhagic fevers caused by pathogens belonging to the first pathogenicity group. The review describes the principle of LAMP operation, which is based on the use of chain-displacing activity of DNA polymerase. The advantages of the method, such as high sensitivity and specificity, simplicity of implementation and cost-effectiveness, are considered in detail. Various methods for detecting LAMP results are also discussed, including the turbidimetric method, the use of fluorescent dyes and immunochromatographic analysis. It is noted that LAMP has some limitations, such as the complexity of primer selection and the possibility of false negative results in the presence of mutations in the genome. However, in general, the method seems promising for rapid detection of viruses in the field. The review provides information on the developed diagnostic test systems based on LAMP for detecting RNA of especially dangerous viruses belonging to the Filoviridae and Arenaviridae families. It is noted that despite the promise of the method, at present none of the described test systems are registered or produced on a commercial basis. The conclusion emphasizes the need to develop and implement new methods for diagnosing dangerous viral infections to control the epidemiological situation and develop a strategy for anti-epidemic measures. LAMP is considered a promising method for creating rapid and cost-effective tests.

The recent discovery of the Yezo virus (YEZV) in Japan and China has raised particular concern due to its potential to cause human diseases ranging from mild febrile illnesses to severe neurological disorders. We report, for the first time, the detection of five YEZV isolates in I. persulcatus ticks from three regions of Russia. The analysis was performed using 5318 ticks of two Ixodes genus collected in 2024 from 23 regions of Russia. The minimum infection rate of YEZV in Russia among I. persulcatus ticks was 0.12% (95% CI: 0.05–0.28). The westernmost and northernmost YEZV detection points have been recorded. YEZV isolates circulating in Russia are genetically diverse. Protein domains of Russian YEZV isolates’ genomes were characterized using HMMER, AlphaFold 3, and InterProScan. The YEZV nucleoprotein (N) of Russian isolates has a racket-shaped structure with “head” and “stalk” domains similar to those of Orthonairovirus haemorrhagiae. The Lys261–Arg261 substitution in the YEZV N Chita 2024-1 isolate occurs in the α11 structure in the region of interaction with viral RNA. Our results show that the distribution area of YEZV is much wider than previously known, provide new data on complete YEZV genomes, extend our structural insight into YEZV N, and suggest a potential target for antiviral drug development to treat YEZV infection.