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Currently, the use of special dust-suppressing reagents is promising to reduce the level of dust in the vicinity and on the territories of pits, mining and processing plants and other facilities with a high content of fine dust. The analysis of ways to reduce the dust-forming ability of inorganic dispersions with a high degree of dusting is carried out. Due to the lack of regulatory and technical documentation devoted to the standardization of quality control methods for dust-suppressing compounds, it becomes necessary to analyze existing parameters and methods for their determination in order to develop mandatory methods for controlling the properties of dust-suppressing compounds, films formed by them and consolidated systems. The study is devoted to substantiating the necessary methods for assessing the dust-forming ability of inorganic dispersions after treatment with various dust suppressants and evaluating their effectiveness. The parameters are considered and methods for quantifying the determination of the quality of the consolidated layer of dust samples using different dust-suppressing compositions are described. As a result of the analysis of the set of parameter values, it was found that the most resistant to the effects of negative factors due to the formation of a denser and more durable polymer matrix mesh are dusting surface samples treated with an emulsion of alkyd glypthalic resin on a water basis with a high agglomerating effect on particles of inorganic dispersion and the formation of a consolidated layer with a wetting angle of 92.5° and a compressive strength 0.56 MPa.

Relevance. Hemorrhagic fever with renal syndrome (HFRS) and tick-borne encephalitis (TBE) are the most common natural focal diseases of viral etiology In Russia. The medical and social significance of these two infections is determined by the extensive fociof their spread, high annual morbidity rates in the population, and the possibility of developing severe forms of the disease leading to permanent disability and death. The causative agents of HFRS In Russia are 6 types of hantaviruses Hantaan, Amur, Seoul, Puumala, Kurkino and Sochi, which, immunologically and genetically significantly different from each other, support their existence in nature through six different species of small mammals, which are sources of infection in humans. TBE virus strains that cause disease in humans belong to five phylogenetically distinct subtypes, including: Far Eastern, European, Siberian, “178-79” and Baikal. Aim. Analysis of the role of small mammals and ticks in the ecology of HFRS and TBE pathogens. Conclusions. Small mammals retain and transmit hantaviruses to uninfected animals and ticks. At the same time, ticks retain and transmit to ticks and mammals not only the TBE virus, but also hantaviruses. Despite the taxonomic difference between the viruses that cause HFRS and TBE, some of their ecological properties are similar.

ABSTRACTTick-borne encephalitis virus (TBEV) causes a severe disease, tick-borne encephalitis (TBE), that has a substantial epidemiological importance for Northern Eurasia. Between 10,000 and 15,000 TBE cases are registered annually despite the availability of effective formaldehyde-inactivated full-virion vaccines due to insufficient vaccination coverage, as well as sporadic cases of vaccine breakthrough. The development of improved vaccines would benefit from the atomic resolution structure of the antigen. Here we report the refined single-particle cryo-electron microscopy (cryo-EM) structure of the inactivated mature TBEV vaccine strain Sofjin–Chumakov (Far-Eastern subtype) at a resolution of 3.0 Å. The increase of the resolution with respect to the previously published structures of TBEV strains Hypr and Kuutsalo-14 (European subtype) was reached due to improvement of the virus sample quality achieved by the optimized preparation methods. All the surface epitopes of TBEV were structurally conserved in the inactivated virions. ELISA studies with monoclonal antibodies supported the hypothesis of TBEV protein shell cross-linking upon inactivation with formaldehyde.

ABSTRACTThe main approach to preventing tick-borne encephalitis (TBE) is vaccination. Formaldehyde-inactivated TBE vaccines have a proven record of safety and efficiency but have never been characterized structurally with atomic resolution. We report a cryoelectron microscopy (cryo-EM) structure of the formaldehyde-inactivated TBE virus (TBEV) of Sofjin-Chumakov strain representing the Far-Eastern subtype. A 3.8 Å resolution reconstruction reveals the structural integrity of the envelope E proteins, specifically the E protein ectodomains. The comparative study shows a high structural similarity to the previously published structures of the TBEV European subtype strains Hypr and Kuutsalo-14. A fraction of inactivated virions exhibits asymmetric features including the deformations of the membrane profile. We propose that the heterogeneity is caused by inactivation and perform a local variability analysis on the small parts of the envelope protein shell to reveal membrane curvature features possibly induced by the inactivation. The results of this study will have implications for the design of novel vaccines against diseases caused by flaviviruses.

Relevance. Lyme disease (LD) remains an important public health problem, especially in Russia, where the incidence is consistently high. To date, there is still no available vaccine against LD, and prevention involves non-specific measures. Aim: to review the literature and summarise data on progress, approaches and strategies for LD vaccine development. Conclusions. The first LD vaccines were developed in the 1990s. An OspA-based vaccine (LYMErix) was commercially available in the early 2000s but not widely distributed. An important milestone in the development of LD vaccines was the shift from the development of monovalent vaccines based on a single type of outer surface protein to the development of multivalent combinations that provide protection against different Borrelia genospecies. A multivalent OspA-based vaccine (VLA15) is in phase III clinical trials and is likely to be the next LD vaccine available on the market. New genetic strategies for vaccine development, identification of new immunogens, and development of vaccines targeting different parts of the LD transmission cycle are of broad interest for further development of LD vaccines.

Objective: to present a clinical case of an 11-year-old child who underwent repeat heart transplantation (HT) at Almazov National Medical Research Centre in St. Petersburg, Russia.Materials and methods. A case of successful heart retransplantation in an 11-year-old child with cardiac allograft vasculopathy (CAV) is presented.Results. The postoperative period after heart retransplantation had no significant differences with the postoperative period of primary heart recipients. The complexity of the intraoperative stage was determined by pronounced adhesions. As part of preoperative preparation, the patient underwent chest CT scan, which, in our experience, allows us to evaluate the heart syntopy and, in turn, is an important preparatory stage in planning repeat interventions.Conclusion. Our first experience of cardiac retransplantation in pediatric patients suggests that repeat HT is the most optimal treatment for pediatric patients with CAV and requires more thorough preoperative preparation.

Introduction. Flaviviruses, possessing natural neurotropicity could be used in glioblastoma therapy using attenuated strains or as a delivery system for antitumor agents in an inactivated form. Objective. To investigate the sensitivity of glioblastoma and pancreatic carcinoma cell lines to vaccine strains of yellow fever and tick-borne encephalitis viruses. Materials and methods. Cell lines: glioblastoma GL-6, T98G, LN-229, pancreatic carcinoma MIA RaCa-2 and human pancreatic ductal carcinoma PANC-1. Viral strains: 17D yellow fever virus (YF), Sofjin tick-borne encephalitis virus (TBEV). Virus concentration were determined by plaque assay and quantitative PCR. Determination of cell sensitivity to viruses by MTT assay. Results. 17D YF was effective only against pancreatic carcinoma tumor cells MIA Paca-2 and had a limited effect against PANC-1. In glioblastoma cell lines (LN229, GL6, T98G), virus had no oncolytic effect and the viral RNA concentration fell in the culture medium. Sofjin TBEV showed CPE50 against MIA Paca-2 and a very limited cytotoxic effect against PANC-1. However, it had no oncolytic effect against glioblastoma cell lines (LN229, T98G and GL6), although virus reproduction continued in these cultures. For the GL6 glioblastoma cell line, the viral RNA concentration at the level with the infection dose was determined within 13 days, despite medium replacement, while in the case of the LN229 cell line, the virus concentration increased from 1 × 109 to 1 × 1010 copies/ml. Conclusion. Tumor behavior in organism is more complex and is determined by different microenvironmental factors and immune status. In the future, it is advisable to continue studying the antitumor oncolytic and immunomodulatory effects of viral strains 17D YF and Sofjin TBEV using in vivo models.

Introduction. Infection of cells with encephalomyocarditis virus type 1 (EMCV-1, Cardiovirus A: Picornaviridae) is accompanied by suppression of cellular protein synthesis. The main role in the inhibition of cellular translation is assigned to the L and 2A «security» proteins. The mechanism of the possible influence of the L protein on cellular translation is unknown. There are hypotheses about the mechanism of influence of 2A protein on the efficiency of cap-dependent translation, which are based on interaction with translation factors and ribosome subunits. However, the available experimental data are contradictory, obtained using different approaches, and do not form a unified model of the interaction between the L and 2A proteins and the cellular translation machinery. Aim. To study the role of L and 2A «security» proteins in the suppression of translation of cellular proteins and the efficiency of translation and processing of viral proteins in infected cells. Materials and methods. Mutant variants of EMCV-1 were obtained to study the properties of L and 2A viral proteins: Zfmut, which has a defective L; Δ2A encoding a partially deleted 2A; ZfmutΔ2A containing mutations in both proteins. Translational processes in infected cells were studied by Western-blot and the pulse method of incorporating radioactively labeled amino acids (14C) into newly synthesized proteins, followed by radioautography. Results. The functional inactivation of the 2A protein does not affect the inhibition of cellular protein synthesis. A direct correlation was found between the presence of active L protein and specific inactivation of cellular protein synthesis at an early stage of viral infection. Nonspecific suppression of the translational processes of the infected cell, accompanied by phosphorylation of eIF2α, occurs at the late stage of infection. Partial removal of the 2A protein from the EMCV-1 genome does not affect the development of this process, while inactivation of the L protein accelerates the onset of complete inhibition of protein synthesis. Partial deletion of the 2A disrupts the processing of viral capsid proteins. Suppression of L protein functions leads to a decrease in the efficiency of viral translation. Conclusion. A study of the role of EMCV-1 L and 2A proteins during the translational processes of an infected cell, first performed using infectious viral pathogens lacking active L and 2A proteins in one experiment, showed that 2A protein is not implicated in the inhibition of cellular translation in HeLa cells; L protein seems to play an important role not only in the specific inhibition of cellular translation but also in maintaining the efficient synthesis of viral proteins; 2A protein is involved not only in primary but also in secondary processing of EMCV-1 capsid proteins.

Hemorrhagic fever with renal syndrome (HFRS) and tick-borne encephalitis (TBE) are the most common viral diseases in Russia. HFRS is caused by six different types of hantaviruses: Hantaan, Amur, Seoul, Puumala, Kurkino, and Sochi, which are transmitted to humans through small mammals of the Muridae and Cricetidae families. TBE is caused by viruses belonging to five different phylogenetic subtypes. The similarities in the ecology of HFRS and TBE pathogens is presented here. Hantavirus-infected small mammals can transmit the virus to uninfected animals, and ticks can also transmit hantavirus to other ticks and mammals. Hantavirus transmission from ticks to humans is possible only hypothetically based on indirect data. Over the past 23 years, 164,582 cases of HFRS (4.9 per 105 people) and 71,579 cases of TBE (2.5 per 105 people) were registered in Russia. The mortality rate was 0.4% (668 cases) in HFRS and 1.6% deaths (1136 cases) in TBE. There were 4030 HFRS (2.5%) and 9414 TBE (13%) cases in children under 14 years old. HFRS and TBE cases were registered in 42 out of 85 Russian regions; in 18—only HFRS, in 13—only TBE, and 12 had no reported cases. The prospects of applying a combined vaccine for HFRS and TBE prevention are shown in this paper.

Oncolytic viral therapy is a promising approach for treating tumors. Oncolytic viruses can directly lyse tumor cells and indirectly activate antitumor immunity. Alphaviruses, as oncolytic viruses, are particularly promising agents because they can selectively infect and lyse tumor cells, modulate microtumor environment, elicit immune-mediated lysis of tumor cells, and serve as a platform for transgene delivery. To ensure safety, attenuated strains of Alphaviruses are typically used for genetic engineering, and immunogenic tumor-associated antigens or cytokines are commonly chosen as transgenes. Studies evaluating both in vitro and in vivo oncolytic and immunomodulatory effects of Alphaviruses and vectors based on them have been growing exponentially. Animal models of various tumor types were used to examine the effectiveness of Alphaviruses, including Sindbis, Semliki Forest virus, Geta (strain M1), Venezuelan equine encephalitis virus, and vectors based on them. Additionally, Alphaviruses revealed enhanced antitumor activity while used in combination therapies with other oncolytic viruses. Alphavirus-like replicon particles based on attenuated Venezuelan equine encephalitis virus may serve for transgene delivery to express heterologous proteins at high levels, and induce both humoral and cellular immune responses. An alphaviral vector-based vaccine, encoding the HER2 extracellular and transmembrane domains, has demonstrated safety and efficacy in preclinical mouse models, as well as in phase I clinical trials for advanced breast cancer patients with HER2 overexpression. This vaccine is known to be safe, effective, and capable of inducing T-cell immunity. In this review, we discuss the current progress in preclinical and clinical investigations, as well as the future potential of Alphaviruses for oncolytic virotherapy.

Relevance. The Sverdlovsk district is a tense natural focus for Lyme borreliosis (LB) with a constantly recorded incidence that exceeds these indicators in the Russian Federation and the Ural Federal region several times. LB is registered on 56 of 59 administrative territories of the district. Currently, the count of LB in the Russian Federation includes both infections caused by Borrelia burgdorferi sensu lato group Borrelia and infections caused by Borrelia miyamotoi sensu lato group Borrelia.Aim. To characterize the epidemic process of LB in the territory of the Sverdlovsk district over a 20-year period (2002–2021).Materials and methods. The paper uses data from federal and regional statistical observations, reporting materials of the Department of Rospotrebnadzor in the Sverdlovsk district for 2002–2021, methods of statistical analysis.Results and discussion. During the follow–up period (2002–2021), the incidence rate of BL in the Sverdlovsk district exceeded the average long-term level in the Russian Federation by almost 3 times, and in the Ural Federal region – by 1.8 times. Among the mechanisms and ways of transmission of LB pathogens, the vector-borne mechanism dominated (84.5%), the share of the unidentified pathway was 15.4%, alimentary (when using raw goat's milk) – 0.1%. The duration of the epidemic season for LB in the district was 10 months (from March to December) with a peak incidence in June. Cases of LB were registered among people of different ages, with a predominance in the group of 60 years and older (39.1%). An analysis of the distribution of people with LB by social composition showed that pensioners prevailed among them – 36.3%, officials made up 27.8%, unemployed – 14.1%. Among the cases, a high proportion of schoolchildren and children under 7 years old were noted. It was found that erythematous and non-erythematous forms of LB are registered in the district, with a predominance of erythematous (64.5%). The main etiological agent of the erythematous form is Borrelia garinii, while the non-erythematous form is Borrelia miyamotoi and B. garinii. In the general structure of morbidity, the number of cases of LB is largely determined by the city inhabitants (92.9%). There were no fatal outcomes in LB in the territory of the district during the studied period.Conclusions. Due to the lack of vaccination of LB worldwide, the only strategy to reduce the incidence of LB is non-specific prevention and timely diagnosis of the disease, including data from epidemiological history, clinical and laboratory diagnostics. The long-term clinical and epidemiological and laboratory studies conducted by us in the Sverdlovsk district allowed us to characterize the main manifestations of the epidemic process of LB and to improve the diagnosis of the disease.

Relevance. Despite the ongoing program of mass vaccination of tick-borne encephalitis (TBE) for more than 20 years in the Sverdlovsk district, the incidence rate of TBE continues to exceed the average in Russia and the Ural Federal region.Aim. To analyze the main indicators of the manifestation of the epidemic process of TBE in the territory of the Sverdlovsk district under the conditions of planned vaccination over a 20-year period (2002–2021).Materials and methods. The article uses data from federal and regional statistical observations, reporting materials of the Department of Rospotrebnadzor in the Sverdlovsk district for 2002-2021, methods of statistical analysis.Results and discussion. During the study period (2002-2021), 3861 cases of TBE were registered in the Sverdlovsk district, while the highest incidence rate was detected in 2005 – 10.1 per 100 thousand population, and the lowest in 2020 – 1.0 per 100 thousand population. The share of the vector-borne mechanism was 78.4%, the unidentified path – 20.1%, alimentary – 1.5%. Analysis of the seasonal distribution of cases of TBE showed that the incidence is recorded from April to November. Cases of TBE were recorded in all age groups, including the child population. Most often, people aged 60 years old and older (24.6%) were ill with TBE. Among the children's population, the largest share fell on children aged 7–14 years (5.4%). Men of working age prevailed among the patients (66.0%). TBE was mainly registered among the unvaccinated population (81.5%) with a predominance of urban (86.1%). Officials predominated among the sick persons – 29.8%, pensioners made up 22.3%, unemployed – 19.8%. Persons whose work is professionally connected with the forest made up only 0.6%. The ongoing program of mass vaccination of TBE has led to a decrease in the proportion of severe and moderate forms of diseases (focal – 9.8% and meningeal – 24.0%) and an increase in the proportion of febrile (33.8%) and atypical forms (32.4%). Deaths during the studied period were recorded mainly among the adult unvaccinated population.Conclusions. The Sverdlovsk district continues to be a tense natural focus of TBE with a constantly recorded incidence among contingents of different age and social groups. In the absence of highly effective etiotropic drugs for the treatment of TBE, the only strategy for reducing the incidence of TBE, the development of severe forms and deaths in the territory of the Sverdlovsk district is mass vaccination of the population.

The COVID-19 pandemic has altered respiratory infection patterns in pediatric populations. The emergence of the SARS-CoV-2 Omicron variant and relaxation of public health measures have increased the likelihood of coinfections. Previous studies show conflicting results regarding the impact of viral and bacterial coinfections with SARS-CoV-2 on severity of pediatric disease. This study investigated the prevalence and clinical impact of coinfections among children hospitalized with COVID-19 during the Omicron wave. A retrospective analysis was conducted on 574 hospitalized patients aged under 18 years in Russia, from January 2022 to March 2023. Samples from patients were tested for SARS-CoV-2 and other respiratory pathogens using qRT-PCR, bacterial culture tests and mass spectrometry, and ELISA. Approximately one-third of COVID-19 cases had coinfections, with viral and bacterial coinfections occurring at similar rates. Adenovirus and Staphylococcus aureus were the most common viral and bacterial coinfections, respectively. Viral coinfections were associated with higher fevers and increased bronchitis, while bacterial coinfections correlated with longer duration of illness and higher pneumonia rates. Non-SARS-CoV-2 respiratory viruses were linked to more severe lower respiratory tract complications than SARS-CoV-2 monoinfection. These findings suggest that during the Omicron wave, seasonal respiratory viruses may have posed a greater threat to children’s health than SARS-CoV-2.

Non-human primates, due to their similarities in immune response to humans, are the preferred model for studying infectious processes and any associated cognitive impairments. Behavioral tests are indispensable for investigating pathogenesis in neuroinfections, especially those that do not manifest with noticeable clinical symptoms, as well as in the transition to a chronic form of the disease. Modeling viral infection requires specialized experimental conditions. Our work describes techniques for investigating mnemonic functions, tiredness, attentional focus, quick-wittedness, and basic behavioral responses in primates under the assumed conditions for infections with viruses that do not have an airborne route of transmission. It also outlines approaches to the training and selection of primates for virological research, as well as analyzing gender differences in learning abilities, the impact of housing conditions on the results, and the correlation between training success and behavioral test scores. These methods will allow a more detailed study of non-human primates as a model for researching cognitive and behavioral impairments under infectious and immune stress, as well as the design of less energy-intensive experiments for evaluating the efficacy and safety of therapeutic and prophylactic strategies at early stages of infection.

An increase in cases of chikungunya fever is reported in the Caribbean, Central and South America, and Southeast Asia. As there is no specific treatment for this disease and the only available treatment is symptomatic, it is very relevant to develop vaccines against chikungunya fever. To develop an inactivated whole-virion vaccine against the disease, it is important to choose a susceptible cell culture that both provides high virus yields and is used for vaccine production.The aim of the study was to evaluate the susceptibility of multiple cell lines to Chikungunya virus infection and to select the monolayer culture method with the highest virus accumulation and yield.Materials and methods. The study used the CHIKV_Nic strain of the Chikungunya virus and cell lines C6/36 (for virus titration), CEF, MRC-5, Vero, and 4647. While choosing the culture method, the authors used culture flasks, a cell factory, and roller bottles. The authors determined the susceptibility of the cell lines to viral infection by the degree of accumulation of the infectious agent in the culture fluid. The results of virus titration were calculated on day 5 on the basis of a pronounced viral cytopathic effect.Results. The Vero and 4647 cell lines demonstrated the highest susceptibility to infection and virus concentrations in the culture fluid. The СEF and MRC-5 cell lines accumulated the virus at lower concentrations. The maximum virus titres (7.10–7.75 log10 TCID50/mL) were observed in the culture fluid 48 h after infection. The optimal multiplicity of infection (MOI) ranged between 0.001 and 0.0001 MOI/cell. At 0.0001 MOI/cell, the virus accumulated in the Vero cells cultured in roller bottles on day 2, with the maximum virus titre being 8.6±0.2 log10 TCID50/mL.Conclusions. Vero cells meet the safety and stability requirements set for the production of chikungunya vaccines. The study determined the minimum MOI of the Chikungunya virus for cell culture. The roller bottle culture method provides the highest cell culture yield and the highest titre of the virus in the culture fluid.

Despite the improvement of endovascular technologies, the method of choice for multi-vascular lesions of the coronary arteries today remains coronary bypass surgery. However, in a range of patients, it is possible to perform hybrid revascularization – a technique with minimal injury that preserves good long-term results similar to those of coronary bypass surgery. The review analyzes current data from the world literature and current trends in the choice of the revascularization method.

Relevance. The Sverdlovsk region is a highly endemic territory for infections transmitted by ixodic ticks. The possibilities of laboratory diagnostics of tick–borne infections in the routine practice of a clinician in the region today are limited mainly by testing blood serum for antibodies to the tick-borne encephalitis virus (TBE virus) and Lyme disease (LD) pathogens – Borrelia burgdorferi sensu lato complex, therefore, among tick-borne infections in the region currently mainly TBE and LD are registered. In case of negative results for antibodies to the pathogens of the above infections, the diagnosis may remain unknown. Aims. To study the etiological structure of infections transmitted by ixodic ticks in the Sverdlovsk region at the present stage, as well as to characterize the epidemiological and clinical features of the course of tick-borne infections detected in conditions of a combination of natural foci. Materials and methods. The study included 227 patients undergoing inpatient or outpatient treatment during the epidemic season of tick activity in 2021 (June-August) at LLS MO "New Hospital" (Urban Center of Natural Focal Infections). The case histories (epidemiological, clinical and laboratory indicators) were studied from each patient, as well as the material (blood) was examined prospectively and retrospectively using molecular biological (PCR) and serological (ELISA, planar protein biochip) methods. Results and discussion. During the study, six diseases were identified among the examined patients: TBE, LD (erythematous and nonerythematous forms), Borrelia miyamotoi disease (BMD), human granulocytic anaplasmosis (HGA), human monocytic ehrlichiosis (HME), as well as "Viral fever transmitted by arthropods" (VFTA). Among the examined patients, the proportion of patients with monoinfection was 49,5%, with mixed infection – 50,5%. Additional studies conducted by us using specific PCR for the presence DNA rickettsia and the causative agent of Q-fever in the blood of patients gave negative results. The general epidemiological characteristics for the above identified infections were the vector-borne mechanism, the prevalence of diseases in groups of middle-aged and elderly people, the largest number of cases of infection with pathogens of any tick-borne infection occurred in Yekaterinburg and its surroundings, for all infections, the duration of tick bite in most cases did not exceed one day; there were differences by sex, incubation period. Clinical symptoms were similar, except for the erythematous form of LD (the presence of erythema migrans at the byte site of tick), because the vast majority of patients had a general infectious syndrome; general laboratory indicators varied. Confirmation of the diagnosis was based on the results of the complex application of molecular biological and serological research methods. Conclusions. The modern etiological structure of infections transmitted by ixodic ticks in the Sverdlovsk region is represented not only by TBE and LD, but also by new disease to our country, such as BMD, HGA, HME, while a high proportion of mixed infections in various combinations has been revealed.

Relevance. Despite the successes achieved over the 85-year history of the study of tick-borne encephalitis (TBE), there are still many controversial and unresolved issues. It is obvious that in the second decade of the XXI century, this natural focal neuroinfection, as before, poses a great threat to public health not only in Russia, but also in endemic countries of the world. Aim. To present modern aspects of etiology, epidemiology, diagnosis, specific prevention of TBE in Russia and endemic countries of the world. Conclusions. Currently, there are 4 genotypes of the TBE virus: Far Eastern, European, Siberian and Baikal, each of which has its own area, pathogenic potential for humans. Nosoareal of TBE covers most of the territory of Russia, 29 European countries. Cases of TBE disease or viral activity are registered in six Asian countries. For the correct verification of the diagnosis, criteria for the diagnosis of cases of the disease have been developed, which mainly concern unvaccinated persons. Since highly effective etiotropic drugs for the treatment of TBE have not yet been developed, the only strategy for reducing the incidence of TBE is mass vaccination of the population of endemic regions. Due to the increase in the rate of vaccination in Russia and European countries, in order to improve epidemiological surveillance of TBE, standards for specific laboratory diagnosis of the disease among vaccinated persons, clarification of the causes of the incidence of vaccinated, as well as deaths among them, need to be clarified. In conditions of combination of natural foci of TBE and other tick-borne infections, it is important to develop diagnostic algorithms, including differential diagnosis of this disease with other infections transmitted by Ixodic ticks.

Cryo-EM structures of E. coli F1Fo ATP synthase highlight the role of the inhibitory ε subunit in regulating the torsional movement of the central stalk within the Fo motor and central stalk flexibility in coupling the F1 and Fo motors.

Although unprecedented efforts aiming to stop the COVID-19 pandemic have been made over the past two years, SARSCoV-2 virus still continues to cause intolerable health and economical losses. Vaccines are considered the most effective way to prevent infectious diseases, which has been reaffirmed for COVID-19. However, in the context of the continuing virus spread because of insufficient vaccination coverage and emergence of new variants of concern, there is a high demand for vaccination strategy amendment. The ability to elicit protective immunity at the entry gates of infection provided by mucosal vaccination is key to block virus infection and transmission. Therefore, these mucosal vaccines are believed to be a “silver bullet” that could bring the pandemic to an end. Here, we demonstrate that the intranasally delivered Gam-COVID-Vac (Sputnik V) vaccine induced a robust (no less than 180 days) systemic and local immune response in mice. High immunogenic properties of the vaccine were verified in non-human primates (common marmosets) by marked IgG and neutralizing antibody (NtAb) production in blood serum, antigen-specific Tcell proliferation and cytokine release of peripheral blood mononuclear cells accompanied by formation of IgA antibodies in the nasal mucosa. We also demonstrate that Sputnik V vaccine can provide sterilizing immunity in K18-hACE2 transgenic mice exposed to experimental lethal SARS-CoV-2 infection protecting them against severe lung immunopathology and mortality. We believe that intranasal Sputnik V vaccine is a promising novel needle-free mucosal vaccine candidate for primary immunization as well as for revaccination and is worth further clinical investigation.

Objectives: The detection of a vaccine-derived poliovirus (VDPV) requires an epidemiological assessment and response. Using repeated stool sampling from a child who is immunocompetent and was vaccinated against poliomyelitis with acute flaccid paralysis, a case of an extremely rapid evolution of Sabin-like poliovirus (PV) type 3 was traced in the child's body. Methods: The case was independently identified in two countries—Tajikistan and Russia. Stool samples for the study were also independently collected in two countries on different days from the onset of paralysis. Virological, serological, and molecular methods; full genome Sanger; and high-throughput sequencing were performed to characterize isolates. Results: PV isolates from samples collected on days 2, 3, and 14 contained eight, seven, and seven mutations in the VP1-coding region, respectively, and were classified as Sabin-like PV type 3. The isolates from samples collected on days 15 and 18 had 11 mutations and were classified as vaccine-derived PVs, which required an epidemiological response in the two countries. Conclusion: The results indicate the need to continue acute flaccid paralysis surveillance, maintain high vaccination coverage, and develop and introduce new effective, genetically stable PV vaccines.

In the Russian Federation, the vaccine against hemorrhagic fever with renal syndrome is at the stage of preclinical and clinical trials. The aim of the study was to analyze an effect of vaccine schedule on neutralizing antibodies (nAB) dynamics in guinea pig models applied with experimental Puumala virus based hantavirus vaccine (HV). Quantitative evaluation of neutralizing antibodies was presented as antibody titer geometric mean expressed in binary logarithms (log2) by the 50% reduction of focus-forming units (FRNT50) in Vero cell in the focus reduction neutralization test. The HV dual inoculation to guinea pigs was carried out in 14 day intervals, booster injection was applied on day 182 after the onset, in the thigh muscle tissue by using 0.3 ml undiluted (HV-u/d) and in the 1/10 dilution (HV-1/10). nAB titer on day 14 after the first HV-u/d and HV-1/10 injection was measured to be at titer of 5.50.3 and 4.80.3, respectively. After the second injection, the nAB peak was as high as 90.2 on day 42 after the first HV-u/f injection, and 6.50.2 on day 14 after the HV-1/10 injection. nAB decreased down to 6.20.3 and 50.3, respectively, on day 364 after the first injection. The booster HV-u/d and HV-1/10 injection induced increase in nAB up to 9.50.3 and 6.50.3, respectively. After the booster injection, it induced significantly higher nAB observed on day 238 after the first HV-u/d injection and delayed up to the 294 day for the HV-1/10. The results of the study indicated the early formation of the immune response, long-term nAB persistence and significantly enhanced immune response after the booster injection on day 182, which indicated a potential for the booster injection a year later. The immunological efficacy and protective activity of the vaccine schedule may be finally assessed according to the results of clinical trials.

Relevance. The production and quality control of any drugs are strictly regulated. In the case of antiviral vaccines, the requirements for their safety and protective activity are getting tougher every year. Vaccine manufacturers face three tasks: ensuring high immunogenicity, safety and availability of the drug. During the development and production of immunobiological drugs, manufacturers must demonstrate sufficient purification from technological impurities to ensure the purity of the drug. Technological impurities directly depend on the technological process and the expression systems used. The Vero cell line has been widely used in the production of various antiviral vaccines for many decades. Thus, the improvement of technological processes for the purification of vaccine preparations from proteins and DNA of Vero cells is still matter of current interest.Aims. Selection of resins and reagents for ion exchange chromatography to reduce the amount of technological impurities in the inactivated polio vaccine production.Materials and Methods. To obtain viral suspensions, producer cultures were infected with poliovirus type 1 (Sabin strain LSc 2ab), type 2 (Sabin strain P712 Ch 2ab), and type 3 (Sabin strain Leon 12a1b). Multiplicity of infection was 0.02 ± 0.01 TCD50/cell. To evaluate the efficiency of ion-exchange chromatography we determined the degree of purification of fractions from ballast proteins, the degree of purification of fractions from residual cellular DNA, and the degree of extraction of the target antigen using specific formulas.Results and discussion. More than 80 experiments have been performed to purify type 1, type 2, and type 3 poliovirus concentrates using various sorbents. In quality control of purified concentrates of type 1, type 2 and type 3 polioviruses, in addition to analysis for total protein, an analysis was performed for the presence of Vero cell proteins.Conclusion. The use of the proposed modifications of purification of concentrates of Sabin strains of poliovirus types 1, 2 and 3 using ion exchange chromatography allows to obtain inactivated viral products that meet the requirements of WHO and the European Pharmacopoeia both in biochemical parameters (the content of host-cell DNA and the content of ballast proteins, including host-cell proteins) and specific activity (D-antigen content). Furthermore, additional purification of vaccines using ion exchange chromatography allows to reduce the content of residual cellular DNA to almost zero, which makes the inactivated polio vaccine the most attractive for its inclusion in various combined vaccines.

The EMCV L and 2A proteins are virulence factors that counteract host cell defense mechanisms. Both L and 2A exhibit antiapoptotic properties, but the available data were obtained in different cell lines and under incomparable conditions. This study is aimed at checking the role of these proteins in the choice of cell death type in three different cell lines using three mutants of EMCV lacking functional L, 2A, and both proteins together. We have found that both L and 2A are non-essential for viral replication in HeLa, BHK, and RD cell lines, as evidenced by the viability of the virus in the absence of both functional proteins. L-deficient infection led to the apoptotic death of HeLa and RD cells, and the necrotic death of BHK cells. 2A-deficient infection induced apoptosis in BHK and RD cells. Infection of HeLa cells with the 2A-deficient mutant was finalized with exclusive caspase-dependent death with membrane permeabilization, morphologically similar to pyroptosis. We also demonstrated that inactivation of both proteins, along with caspase inhibition, delayed cell death progression. The results obtained demonstrate that proteins L and 2A play a critical role in choosing the path of cell death during infection, but the result of their influence depends on the properties of the host cells.

Relevance. Hemorrhagic fever with renal syndrome (HFRS) is an acute viral zoonosis. Being widespread in Eurasia, it holds a leading place in Russia among natural focal human diseases. The vast majority of HFRS cases in Russia, about 98%, are associated with Puumala virus. The disease is characterized by a wide range of clinical manifestations. Early specific diagnostics appears to be of a great importance for starting timely pathogenic therapy. The aim of the study was to clarify the diagnostic value of detecting hantavirus antibodies in the HFRS suspected patient urine. Materials and methods. Blood sera and urine samples from 68 patients at the Infectious Diseases Hospital in the city of Ufa, obtained with a 2-day interval, as well as urine and blood serum samples from 15 convalescents 1, 2, 3 and 6 months after disease onset were examined for hantavirus antibodies. 53 blood sera and urine samples from patients residing in Moscow, Moscow and Samara regions collected at different time points during the disease course were investigated in parallel. Antibodies were detected by the indirect immunofluorescence method. Results. On day 3, 4, 5 and 6 of disease, while specific antibodies were detected in the blood serum, antibodies in the urine were found in 85.7%, 89.4%, 93.1% and 100% of patients, respectively. The peak quantity of antibodies was excreted in the urine from days 5 to 11, which corresponds to the oliguric stage of the disease. In the convalescent period, antibodies were still detected in urine 1, 2 and 3 months afterwards in 86.7%, 46% and 20% of cases, respectively, but not detected 6 months later, which probably reflects the process of long-term restoration of the kidneys function. A moderate positive correlation between specific antibodies in serum and urine was observed only in the oliguric period of the disease. Conclusions. Detection of hantavirus antibodies simultaneously in blood serum and urine of febrile patients instead of paired blood sera allows to conduct HFRS diagnostics within the very first days of hospitalization and prevent severe complications due to timely pathogenic therapy.

Combined viral and photodynamic therapy for oncological diseases has great potential to treat aggressive tumors such as glioblastomas. A conjugate of vesicular stomatitis virus (VSV) with protoporphyrin IX was prepared, and its oncolytic effects were studied and compared to the effects of the individual components. The VSV showed an oncolytic effect on glioblastoma cell lines T98G and LN229 at a virus titer of 105 TCID50/mL. A VSV titer of 104 TCID50/mL was sufficient for neuroblastoma cell death. A study of the effect of VSV in tumor 3D cell modeling found that VSV had a clear viral cytopathic effect on spheroids of T98G and LN229 cells. Conjugation with the porphyrin significantly reduced the viral titer, but when irradiated, lysis of cells was observed. Photodynamic treatment of T98G and LN229 cells and spheroids with protoporphyrin IX as a photosensitizer also had a cytotoxic effect on cells and, to a lesser extent, on the tumoroids, as complete cell death was not achieved for the tumoroids. The combination therapy, which involved sequential photodynamic therapy using protoporphyrin IX as a photosensitizer and treatment with VSV, was shown to significantly enhance efficacy, resulting in complete cell death of both T98G and LN229 cells and tumoroids. The combination treatment allowed for the use of a lower viral titer (103–104 TCID50/mL) and a lower porphyrin concentration (0.5 μg/mL) to achieve a significant cytotoxic effect. As a result, the implementation of this combination therapy would likely lead to fewer side effects from the treatment. This study clearly demonstrated the excellent perspectives of combination therapy for the treatment of highly aggressive tumors such as glioblastomas. [ABSTRACT FROM AUTHOR]

Tick-borne encephalitis virus (TBEV) and Powassan virus (POWV) are neurotropic tick-borne orthoflaviviruses. They cause mostly asymptomatic infections in hosts, but severe forms with CNS involvement can occur. Studying the early stages of viral infections in humans is challenging, and appropriate animal models are essential for understanding the factors determining the disease severity and for developing emergency prophylaxis and treatment options. In this work, we assessed the model of the early stages of TBEV and POWV mono- and co-infections in Macaca fascicularis. Serological, biochemical, and virological parameters were investigated to describe the infection, including its impact on animal behavior. Viremia, neutralizing antibody dynamics, and viral load in organs were chosen as the main parameters distinguishing early-stage orthoflavivirus infection. Levels of IFNα, monocyte count, and cognitive test scores were proposed as additional informative indicators. An assessment of a tick-borne encephalitis vaccine using this model showed that it provided partial protection against POWV infection in Macaca fascicularis without signs of antibody-dependent enhancement of infection.

Objectives: This study aimed to estimate the impact of the COVID-19 pandemic on the circulation of non-SARS-CoV-2 respiratory viruses and the clinical characteristics of COVID-19 in hospitalized children. Methods: A total of 226 and 864 children admitted to the Children's City Clinical Hospital with acute respiratory infection in September to November of 2018 and 2020 in Moscow were tested for respiratory viruses using multiplex polymerase chain reaction (PCR) and Mycoplasma pneumoniae/Chlamydia pneumoniae using enzyme-linked immunosorbent assay. Results: The detection rate of non-SARS-CoV-2 viruses in 2020 was lower than in 2018, 16.9% versus 37.6%. An increase in the median age of children with respiratory viruses was observed during the pandemic (3 years vs 1 year). There was no significant difference in the frequency of intensive care unit (ICU) admission in children with SARS-CoV-2 and other respiratory virus infections (2.7% vs 2.9%). SARS-CoV-2 and human rhinoviruses, human metapneumoviruses, and human adenoviruses showed significantly lower than expected co-detection rates during co-circulation. An increase in body mass index (BMI) or bacterial coinfection leads to an increased risk of ICU admission and a longer duration of COVID-19 in children. Conclusions: The COVID-19 pandemic led to significant changes in the epidemiological characteristics of non-SARS-CoV-2 respiratory viruses during the autumn peak of the 2020 pandemic, compared with the same period in 2018.

Introduction. In clinical practice, the differential diagnosis of COVID-19 can be challenging during the flu season, entailing serious consequences such as delays in appropriate control measures against the SARS-CoV-2 pandemic. Another problem is posed by co-infection of SARS-CoV-2 and influenza virus (IV), which significantly contributes to the severity of the COVID-19 disease. This study was aimed to explore the cross-impact of co-administration of Russian influenza and COVID-19 vaccines on development of specific immunity in laboratory animals.Materials and methods. The study was conducted on BALB/c mice. The animals were inoculated intramuscularly with the vaccine for COVID-19 prevention (CoviVac) and the vaccine for influenza prevention (Flu-M). The sera from the immunized animals were examined separately. Three IV strains were used in the hemagglutination inhibition assay. Antibodies (Abs) against SARS-CoV-2 were detected by an enzyme-linked immunosorbent assay (ELISA). The neutralization test was performed to detect virus neutralizing antibodies against SARS-CoV-2 and IV.Results. Relatively high titers of specific Abs were found in the groups of animals inoculated with one vaccine and with two vaccines concurrently. In the groups of animals inoculated with CoviVac and with two vaccines concurrently, both in the ELISA test and in the neutralization test, the average titers of specific Abs against SARSCoV- 2 did not demonstrate any statistical difference. The group of animals inoculated concurrently with two vaccines demonstrated statistically higher titers of Abs against IV after the second immunization compared to the group of animals inoculated with Flu-M.Discussion. The study has shown that post-vaccination immunity both to IV and to SARS-CoV-2 develops after co-vaccination with two vaccines. The observed enhanced post-vaccination immune response to IV in the coimmunized laboratory animals needs further research.Conclusion. The performed studies suggest the possibility of co-administration of two vaccines to prevent influenza and COVID-19.

The review provides a brief historical outline of the discovery and study of tick-borne encephalitis (TBE) during three expeditions to the Far East (19371939). As a result of the Far Eastern expeditions, the TBE virus was discovered, numerous strains were isolated, a vector-borne transmission pathway was established, the main features of epidemiology, clinic and pathomorphology of the disease were described, serotherapy was tested, first inactivated "brain" vaccine against TBE was developed and its effectiveness was proved. The history of the discovery and study of TBE is marked by the heroism of researchers and tragic events illness of some participants, death during the development of the first vaccine, arrest of L.A. Zilber and two performers.

Introduction. Cases of Chikungunya fever have been reported in more than 100 countries in Europe, Oceania, Africa, Asia, the Caribbean, and America. The musculoskeletal disorders typical for Chikungunya fever can last from several months to a year and even lead to disability. The infection is believed to provide lifelong immunity. This factor and the lack of specific therapy make vaccination the most promising method for preventing Chikungunya fever.Materials and methods. The purified inactivated preparation with the different doses of the CHIKV antigen was injected intramuscularly to BALB/c mice twice with an interval of 14 days. Indicators of humoral and cellular immunity were assessed in dynamics in ELISA, the neutralization test and proliferation test of splenocytes. Results. The purified preparation containing the CHIKV antigen inactivated by beta-propiolactone had pronounced immunogenic properties. The most prominent immune response in ELISA and neutralization test was registered for a dose of 40 μg. Stimulation with the specific CHIKV antigen caused a pronounced proliferation of animals' splenocytes. The peak values of specific humoral and cellular immunity parameters were registered 14 days after the second injection.Discussion. The purified preparation containing the CHIKV antigen inactivated by beta-propiolactone had demonstrated the sufficient immunogenic properties. The immunizing dose of 40 μg CHIKV selected as a result of the studies caused in BALB/c mice the development of the humoral immunity characterized by the specific IgG with neutralizing activity, and the specific cell immunity characterized by the animals' splenocytes proliferation after stimulation with CHIKV antigen.Conclusion. The purified β-PL inactivated preparation of the CHIKV antigen at a dose of 40 μg to demonstrated pronounced immunogenicity in BALB/c mice after two-dose immunization. The developed preparation can be considered as promising for the prevention of Chikungunya fever using the dose and scheme tested in this study.

Oncolytic viruses offer a promising approach to tumor treatment. These viruses not only have a direct lytic effect on tumor cells but can also modify the tumor microenvironment and activate antitumor immunity. Due to their high pathogenicity, flaviviruses have often been overlooked as potential antitumor agents. However, with recent advancements in genetic engineering techniques, an extensive history with vaccine strains, and the development of new attenuated vaccine strains, there has been a renewed interest in the Flavivirus genus. Flaviviruses can be genetically modified to express transgenes at acceptable levels, and the stability of such constructs has been greatly improving over the years. The key advantages of flaviviruses include their reproduction cycle occurring entirely within the cytoplasm (avoiding genome integration) and their ability to cross the blood–brain barrier, facilitating the systemic delivery of oncolytics against brain tumors. So far, the direct lytic effects and immunomodulatory activities of many flaviviruses have been widely studied in experimental animal models across various types of tumors. In this review, we delve into the findings of these studies and contemplate the promising potential of flaviviruses in oncolytic therapies.

We present the results of a randomized, double-blind, placebo-controlled, multi-center clinical trial phase I/II of the tolerability, safety, and immunogenicity of the inactivated whole virion concentrated purified coronavirus vaccine CoviVac in volunteers aged 18–60 and open multi-center comparative phase IIb clinical trial in volunteers aged 60 years and older. The safety of the vaccine was assessed in 400 volunteers in the 18–60 age cohort who received two doses of the vaccine (n = 300) or placebo (n = 100) and in 200 volunteers in 60+ age cohort all of whom received three doses of the vaccine. The studied vaccine has shown good tolerability and safety. No deaths, serious adverse events (AEs), or other significant AEs related to vaccination have been detected. The most common AE in vaccinated participants was pain at the injection site (p < 0.05). Immunogenicity assessment in stage 3 of Phase II was performed on 167 volunteers (122 vaccinated and 45 in Placebo Group) separately for the participants who were anti-SARS-CoV-2 nAB negative (69/122 in Vaccine Group and 28/45 in Placebo Group) or positive (53/122 in Vaccine Group and 17/45 in Placebo Group) at screening. On Day 42 after the 1st vaccination, the seroconversion rate in participants who were seronegative at screening was 86.9%, with the average geometric mean neutralizing antibody (nAB) titer of 1:20. A statistically significant (p < 0.05) increase in IFN-γ production by peptide-stimulated T-cells was observed at Days 14 and 21 after the 1st vaccination. In participants who were seropositive at screening but had nAB titers below 1:256, the rate of fourfold increase in nAB levels was 85.2%, while in the participants with nAB titers > 1:256, the rate of fourfold increase in nAB levels was below 45%; the participants who were seropositive at screening of the 2nd vaccination did not lead to a significant increase in nAB titers. In conclusion, inactivated vaccine CoviVac has shown good tolerability and safety, with over 85% NT seroconversion rates after complete vaccination course in participants who were seronegative at screening in both age groups: 18–60 and 60+. In participants who were seropositive at screening and had nAB titers below 1:256, a single vaccination led to a fourfold increase in nAB levels in 85.2% of cases. These findings indicate that CoviVac can be successfully used both for primary vaccination in a two-dose regimen and for booster vaccination as a single dose in individuals with reduced neutralizing antibody levels.

Relevance. Travel diarrhea is the most common health problem in travelers, affecting up to 70% of travelers, especially when traveling to developing countries. Research and development of scientific and practical approaches to the prevention, risk assessment and treatment of travelers' diarrhea continues to be the focus of attention of specialists in the field of epidemiology, infectious diseases and travel medicine around the world.Aim of the study: systematization and synthesis of new data on various clinical and epidemiological aspects of travelers' diarrhea.Conclusion. Analysis of modern scientific literature has made it possible to identify the risks for travelers associated with the direction of travel and the state of their own health. The highest risk of developing traveler's diarrhea (from 20% to 90%) is recorded in people visiting the countries of the Middle East, South and Southeast Asia, Central and South America, and Africa. There is a high risk of developing traveler's diarrhea in children under 4 years of age. The causative agents of acute bacterial intestinal infections can account for up to 80% -90% of all cases of travelers' diarrhea. In most cases, travelers' diarrhea is mild. Seeking medical care is observed from 5% to 15% of cases. For etiotropic therapy, the use of azithromycin, ciprofloxacin and other drugs is recommended. Recommendations for self-management of traveler's diarrhea have been formulated. Pre-trip travel advice will help reduce the risks of travelers' diarrhea.

The objective was to evaluate the immediate results of treatment of patients with symptomatic form of myocardial bridges of the coronary arteries.Methods and materials. In the course of a retrospective study, the results of treatment of 70 patients who had underwent drug treatment and 52 patients who had underwent surgical treatment were analyzed. All the subjects had high functional angina pectoris.Results. Pharmacological therapy showed significant positive dynamics in 18 (25.7 %) patients. Analysis of the intraoperative and early postoperative periods in patients who underwent supracoronary myotomy allows us to conclude that surgical treatment of patients with myocardial bridges of the coronary arteries shows satisfactory results.Conclusion. Drug therapy may be effective in some patients with myocardial bridges of the coronary arteries. In case of ineffectiveness of pharmacological treatment, the possibility of performing surgery in the amount of supracoronary myotomy should be considered.

Introduction. Since the development of inactivated polio vaccines, different stages of the production process have been changed and improved. Current production of inactivated polio vaccines based on both wild and attenuated strains includes several technological stages, one of which is the concentration of the virus-containing liquid, which ensures poliovirus concentration, and purification of the virus-containing liquid from a significant part of the ballast components.Research objective is to compare the characteristics of ultrafiltration membranes and select the membranes that provide optimal value of purification and concentration of poliovirus type 1 (Sabin strain).Materials and methods. Laboratory ultrafiltration systems from two manufacturers with 50, 100, and 300 kDa membranes were used for the concentration. Results were evaluated by the content of total protein, which is the main stress for the subsequent purification stages, the value of infectious virus titer in the concentrate, and the content of D-antigen as the target product.Results and discussion. Obtained results demonstrated that the content of the target product (the highest D-antigen content) and purification from impurity proteins (the total protein content in the concentrate) were most optimal when a membrane with a cut-off of 300 kDa was used for concentration. The study also evaluated the real cut-off components by various membranes to determine the composition of the protein load on the target product.Conclusion. In terms of quality of the resulting target product and the manufacturability of the production process, the use of a 300 kDa membrane is the most appropriate when working out the technology for manufacturing inactivated polio vaccine based on Sabin strains of poliovirus and the Vero line as a producing culture.

During 2000–2022, a total of 69 of Russia’s 85 administrative regions reported 164,580 hemorrhagic fever with renal syndrome (HFRS) cases, with an annual average rate of 4.9 cases/100,000 population (105 popul.). European Russia reported 162,045 (98.5%) cases in 53/60 regions with 9.7 cases/105 popul. Asian Russia reported 2535 (1.5%) cases in 16/25 regions with 0.6 cases/105 popul. In the same period, Russia reported 668 (0.4%) fatal HFRS cases, and 4030 (2.4%) cases among children under the age of 14 years. Most HFRS cases occurred during autumn and winter. The incidence among rural residents was 6.7 per 105 popul., higher than the urban 4.4 per 105 popul.; however, among HFRS patients, rural and urban residents account for 35% and 65%, respectively. Six hantaviruses, causing HFRS of different clinical severity, were recognized as pathogens: Hantaan (HTNV) and Amur (AMUV) of Orthohantavirus hantanense species, Seoul (SEOV) of Orthohantavirus seoulense species, Puumala (PUUV) of Orthohantavirus puumalaense species, and Kurkino (KURV) and Sochi (SOCV) of Orthohantavirus dobravaense species, with the principal hosts Apodemus agrarius coreae, Apodemus peninsulae, Rattus norvegicus, Myodes glareolus, Apodemus agrarius agrarius, and Sylvaemus ponticus, respectively. It was found that 97.7% of HFRS cases are caused by PUUV, therefore, this virus plays the main role in the HFRS morbidity structure in Russia.

Hemorrhagic fever with renal syndrome (HFRS) and tick-borne encephalitis (TBE) are the most common viral diseases in Russia. HFRS is caused by six different types of hantaviruses: Hantaan, Amur, Seoul, Puumala, Kurkino, and Sochi, which are transmitted to humans through small mammals of the Muridae and Cricetidae families. TBE is caused by viruses belonging to five different phylogenetic subtypes. The similarities in the ecology of HFRS and TBE pathogens is presented here. Hantavirus-infected small mammals can transmit the virus to uninfected animals, and ticks can also transmit hantavirus to other ticks and mammals. Hantavirus transmission from ticks to humans is possible only hypothetically based on indirect data. Over the past 23 years, 164,582 cases of HFRS (4.9 per 105 people) and 71,579 cases of TBE (2.5 per 105 people) were registered in Russia. The mortality rate was 0.4% (668 cases) in HFRS and 1.6% deaths (1136 cases) in TBE. There were 4030 HFRS (2.5%) and 9414 TBE (13%) cases in children under 14 years old. HFRS and TBE cases were registered in 42 out of 85 Russian regions; in 18—only HFRS, in 13—only TBE, and 12 had no reported cases. The prospects of applying a combined vaccine for HFRS and TBE prevention are shown in this paper. [ABSTRACT FROM AUTHOR]