INTRODUCTION. Rotavirus vaccines based on virus-like particles (VLPs), non-infectious recombinant proteins of human rotavirus A that mimic the structure of the native virus, show promise for preventive vaccination. Presumably, the optimal method to determine the potency of VLP-based rotavirus vaccines is the enzyme-linked immunosorbent assay (ELISA) method used to measure the titre of specific IgG antibodies to rotavirus A proteins in serum samples from vaccinated animals.AIM. This study aimed at assessing the potency of a VLP-based rotavirus vaccine by developing and validating an analytical procedure using ELISA to determine the levels of antibodies to the VP2 and VP6 proteins of rotavirus A in serum samples from vaccinated guinea pigs.MATERIALS AND METHODS. The potency of the VLP-based rotavirus vaccine was determined in vivo in three types of experimental animals, including BALB/c mice, agouti guinea pigs, and newborn minipigs. The animals received three intramuscular injections of the vaccine at a dose of 30 µg. This study used the indirect ELISA method to quantify VP2- and VP6-specific immunoglobulin G (IgG) antibodies and the virus-neutralisation test to measure neutralising antibodies (nAbs) to rotavirus A in animal serum samples. The study involved calculating the geometric mean titres (GMTs) of antibodies. The authors validated the analytical procedure for potency assessment on two batches of the vaccine using standard statistical analysis methods.RESULTS. The study compared VP2- and VP6-specific IgG and nAb levels 14 days after the first, second, and third vaccinations. The authors observed a significant increase in antibody titres and statistically significant (p<0.05) differences between groups as early as after the second vaccination. Double vaccination induced rotavirus-specific IgGs and nAbs in newborn minipigs (GMTs of 200.0 and 108.9, respectively) and guinea pigs (GMTs of 12,800 and 2,600, respectively). Vaccinated mice demonstrated a significant increase in rotavirus-specific IgG levels (GMT of 572,440). Guinea pigs were selected as a relevant model for validating the ELISA-based potency assessment procedure. The validation study used a double vaccination scheme. The validation using two batches of the VLP-based rotavirus vaccine indicated that the ELISA-based analytical procedure met the acceptance criteria for specificity, repeatability, and intermediate precision. The repeatability assessment resulted in a coefficient of variation (CV) of 12.4% for batch 1 and a CV of 7.7% for batch 2, whereas the intermediate precision assessment showed a CV of 6.9% for batch 1 and a CV of 10.2% for batch 2, which were within the acceptance criteria for both validation parameters (CV≤15%).CONCLUSIONS. The authors developed and validated an ELISA-based analytical procedure for assessing the potency of VLP-based preventive rotavirus vaccines. According to the study results, ELISA is applicable to the control of the potency of VLP-based preventive rotavirus vaccines.

This article proposes carbocyclic derivatives of N-acylated esters of L-amino acids with aromatic carboxylic acids as antiviral small-molecule agents. To increase the water solubility of inhibitors that are insoluble in aqueous solutions, the target compounds were used as zinc(II) complexes. It has been shown that hydrophobic organic compounds in the form of zinc(II)-coordinated ligands are capable of suppressing the replication of the influenza A virus strain resistant to adamantane-type drugs. Zinc(II) chloride at the concentration used does not have antiviral or toxic effects in experiments in vitro.

The coronavirus disease (COVID-19) pandemic has brought into sharp relief the threat posed by coronaviruses and laid the foundation for a fundamental analysis of this viral family, as well as a search for effective anti-COVID drugs. Work is underway to update existent vaccines against COVID-19, and screening for low-molecular-weight anti-COVID drug candidates for outpatient medicine continues. The opportunities and ways to accelerate the development of antiviral drugs against other pathogens are being discussed in the context of preparing for the next pandemic. In 2012–2015, Tsyshkova et al. synthesized a group of water-soluble low-molecular-weight compounds exhibiting an antiviral activity, whose chemical structure was similar to that of arbidol. Among those, there were a number of water-soluble compounds based on 5-methoxyindole-3-carboxylic acid aminoalkyl esters. Only one member of this rather extensive group of compounds, dihydrochloride of 6-bromo-5-methoxy-1-methyl-2-(1-piperidinomethyl)-3-(2-diethylaminoethoxy)carbonylindole, exhibited a reliable antiviral effect against SARS-CoV-2 in vitro. At a concentration of 52.0 μM, this compound completely inhibited the replication of the SARS-CoV-2 virus with an infectious activity of 106 TCID50/mL. The concentration curves of the analyzed compound indicate the specificity of its action. Interferon-inducing activity, as well as suppression of syncytium formation induced by the spike protein (S-glycoprotein) of SARS-CoV-2 by 89%, were also revealed. In view of its synthetic accessibility − high activity (IC50 = 1.06 µg/mL) and high selectivity index (SI = 78.6) − this compound appears to meets the requirements for the development of antiviral drugs for COVID-19 prevention and treatment.

Previous studies have shown that complexly shaped nanoparticles (NPs) have their intrinsic radiothermal emission in the millimeter range. This article presents a method for controlling the quality of nanodrugs—immunobiological preparations (IBPs)—based on the detection of their intrinsic radiothermal emissions. The emissivity of interferon (IFN) medicals, determined without opening the primary package, is as follows (µW/m2): IFN-α2b—80 ± 9 (105 IU per package), IFN-β1a—40 ± 5 (24 × 106 IU per package), IFN-γ—30 ± 4 (105 IU per package). The emissivity of virus-like particles (VLP), determined using vaccines Gam-VLP-multivac (120 μg) in an injection bottle (crimp cap vials), was as follows: 12 ± 1 µW/m2, Gam-VLP—rota vaccines—9 ± 1 µW/m2. This study shows the reproducibility of emissivity over the course of a year, subject to the storage conditions of the immunobiological products. It has been shown that accelerated aging and a longer shelf life are accompanied by the coagulation of active NPs, and lead to a manyfold drop in emissivity. The dependence of radiothermal emission on temperature has a complex, non-monotonic nature. The emission intensity depends on the form of dosage, but remains within the order of magnitude for IFN-α2b for intranasal aqueous solution, ointments, and suppositories. The possibility of the remote quantitative control of the first phases of the immune response (increased synthesis of IFNs) to the intranasal administration of VLP vaccines has been demonstrated in experimental animals.

Introduction. The COVID-19 pandemic caused by SARS-CoV-2 has created serious health problems worldwide. The most effective way to prevent the occurrence of new epidemic outbreaks is vaccination. One of the modern and effective approaches to vaccine development is the use of virus-like particles (VLPs). The aim of the study is to develop a technology for production of VLP based on recombinant SARS-CoV-2 proteins (E, M, N and S) in insect cells. Materials and methods. Synthetic genes encoding coronavirus proteins E, M, N and S were used. VLP with various surface proteins of strains similar to the Wuhan virus, Delta, Alpha and Omicron were developed and cloned into the pFastBac plasmid. The proteins were synthesized in the baculovirus expression system and assembled into VLP in the portable Trichoplusia ni cell. The presence of insertion in the baculovirus genome was determined by PCR. ELISA and immunoblotting were used to study the antigenic activity of VLP. VLP purification was performed by ultracentrifugation using 20% sucrose. Morphology was assessed using electron microscopy and dynamic light scattering. Results. VLPs consisting of recombinant SARS-CoV-2 proteins (S, M, E and N) were obtained and characterized. The specific binding of antigenic determinants in synthesized VLPs with antibodies to SARS-CoV-2 proteins has been demonstrated. The immunogenic properties of VLPs have been studied. Conclusion. The production and purification of recombinant VLPs consisting of full-length SARS-CoV-2 proteins with a universal set of surface antigens have been developed and optimized. Self-assembling particles that mimic the coronavirus virion induce a specific immune response against SARS-CoV-2.

A series of N-substituted esters of L-amino acids with various heterocyclic and aromatic carboxylic acids were synthesized. To increase the water solubility of the synthesized compounds, they were used as organic ligands in iron(II), zinc(II), and nickel(II) complexation. The antiviral properties of the resulting aqueous solutions were tested against the influenza virus A/IIV-Orenburg/83/2012(H1N1)pdm09 in vitro. It was shown that complexation with iron(II) was the most successful in achieving a high level of viral reproduction suppression compared to nickel and zinc complexes.

Relevance. Rabies, hydrophobia is an acute viral zoonotic neuroinfection with 100% mortality in the case of clinical signs in humans or animals. The main biological reservoirs and distributors of the rabies pathogen (Lyssa virus, Rhabdo viridae) on the territory of the Russian Federation (RF) are wild predators of the canine family responsible for the circulation of the classic rabies virus (Rabies virus). Also on the territory of the RF and the countries of Eastern Europe, Asia Minor and Central Asia, the circulation of 6 more species of viruses of the genus Lyssavirus, with biological reservation in bat populations, has been established. Despite the existing genetic and environmental differences, all types of lyssaviruses registered in the territory of the RF pose a threat to humans and animals. Due to the growing processes of interpenetration of the anthropogenic environment and wildlife, in recent years, rabies has been increasingly registered in domestic carnivores, which significantly increases epidemiological risks. Aim. A retrospective comparative analysis of data on the incidence of rabies in humans and animals in the RF and on the territory of some regions of Eurasia adjacent to the RF for the period from 2013 to 2021 to characterize the current manifestations of the epidemic (epizootic) process of rabies. Materials and methods. The materials for the study were data from epidemiological surveillance of rabies in the RF and data from veterinary statistics for 2013–2021. Conventional methods and computer programs were used for the analysis: Microsoft Office Excel analysis package, as well as an online statistical calculator. The level of reliability of the data obtained was evaluated using the Pearson consensus criterion χ2, with a reliability level of p = 0.05 and p = 0.01. Results. It is shown that, on average, 2312.33 ± 752.24 cases of rabies in animals were registered on the territory of the RF for the period 2013–2021. With the observed trend towards a gradual decrease in the annual incidence of rabies among animals, the share of dogs and cats in the epizootic process has increased by 7.,4 and 3,8%, respectively, over the past 2 years. At the same time, an increase in the incidence of rabies in humans by 4,33 times was recorded when comparing indicators with the previous period 2018-2019. Russia in total for 2013-2021 ranks first in the number of officially registered cases of rabies in humans (63%) among the countries of Europe, the Caucasus, Transcaucasia and Central Asia. The European part of the RF accounts for 41,7–44,3% of cases of rabies among domestic and farm animals and 46,7% among wild animals compared to these regions. The recorded trend towards a decrease in the number of cases of rabies in animals can be explained by long-term oral vaccination of wild carnivores. But the decrease in the number of natural foci of the disease did not provoke a proportional decrease in the incidence of rabies in domestic animals. As a result, the proportion of dogs and cats in the morbidity structure has significantly increased, which, given their proximity to humans, ensures the maintenance of a high level of epidemiological risk. In the pan-European incidence of rabies, the RF is in second place after the countries of Eastern and Southern Europe. All reported cases of rabies in the RF are caused by the natural circulation of the «classic» rabies virus. In recent years, no lyssaviruses have been detected in bat populations on the territory of the RF, which contrasts with the high incidence of lyssaviruses in other European countries. The RF shares land borders with the countries of Europe, the Caucasus, Transcaucasia and Central Asia, at the same time, the territory of the RF has extensive areas of Eptesicus serotinus and Myotis daubentonii, which are biological reservoirs for EBLV-1, EBLV-2. Based on the above, the risk of the permanent presence of lyssaviruses in bat populations in the territory of the RF is very high and requires monitoring on a regular basis. Conclusion. The analysis of epidemiological and epizootological risks shows the need to adjust the ongoing preventive anti-rabies measures. It is necessary to intensify the campaign of anti-rabies vaccination of domestic carnivores, reduce the number of neglected animals, expand the program for oral vaccination of wild carnivores, monitor the prevalence of lyssaviruses in bat populations in the territory of the RF.

Introduction. Currently, low molecular-weight compounds are being developed as potential inhibitors of CoVs replication, targeting various stages of the replication cycle, such as major protease inhibitors and nucleoside analogs. Viroporins can be alternative protein targets. The aim of this study is to identify antiviral properties of histidine derivatives with cage substituents in relation to pandemic strain SARS-CoV-2 in vitro. Materials and methods. Combination of histidine with aminoadamantane and boron cluster anion [B10H10]2 (compounds IIV) was carried out by classical peptide synthesis. Compound were identified by modern physicochemical methods. Antiviral properties were studied in vitro on a monolayer of Vero E6 cells infected with SARS-CoV-2 (alpha strain) with simultaneous administration of compounds and virus. Results. Derivatives of amino acid histidine with carbocycles and boron cluster were synthesized and their antiviral activity against SARS-CoV-2 was studied in vitro. Histidine derivatives with carbocycles and [B10H10]2 have the ability to suppress virus replication. The solubility of substances in aqueous media can be increased due to formation of hydrochloride or sodium salt. Discussion. 2HCl*H-His-Rim (I) showed some effect of suppressing replication of SARS-CoV-2 at a viral load of 100 doses and concentration 31.2 g/ml. This is explained by the weakly basic properties of compound I. Conclusion. The presented synthetic compounds showed moderate antiviral activity against SARS-CoV-2. The obtained compounds can be used as model structures for creating new direct-acting drugs against modern strains of coronaviruses.

INTRODUCTION:Rotavirus infection is one of the main concerns in infectious pathology in humans, mammals and birds. Newborn piglets or rodents are usually being used as a laboratory model for the evaluation of immunogenicity and efficacy for all types of vaccines against rotavirus A (RVA), and the use of ELISA for the detection of virus-specific antibodies of specific isotype is an essential step of this evaluation.OBJECTIVE:Development of indirect solid-phase ELISA with VP2/VP6 rotavirus VLP as an antigen to detect and assess the distribution of RVA-specific IgG, IgM and IgA in the immune response to rotavirus A.MATERIALS AND METHODS:VP2/VP6 rotavirus VLP production and purification, electron microscopy, PAGE, immunoblotting, ELISA, virus neutralization assay.RESULTS:The study presents the results of development of a recombinant baculovirus with RVA genes VP2-eGFP/VP6, assessment of its infectious activity and using it for VLP production. The morphology of the VP2/VP6 rotavirus VLPs was assessed, the structural composition was determined, and the high antigenic activity of the VLP was established. VLP-based ELISA assay was developed and here we report results for RVA-specific antibody detection in sera of different animals.CONCLUSION:The developed ELISA based on VP2/VP6 rotavirus VLP as a universal antigen makes it possible to detect separately IgG, IgM and IgA antibodies to rotavirus A, outlining its scientific and practical importance for the evaluation of immunogenicity and efficacy of traditional vaccines against rotavirus A and those under development.

Introduction. SARS-CoV-2, a severe acute respiratory illness virus that emerged in China in late 2019, continues to spread rapidly around the world, accumulating mutations and thus causing serious concern. Five virus variants of concern are currently known: Alpha (lineage B.1.1.7), Beta (lineage B.1.351), Gamma (lineage P.1), Delta (lineage B.1.617.2), and Omicron (lineage B.1.1.529). In this study, we conducted a molecular epidemiological analysis of the most prevalent genovariants in Moscow and the region. The aim of the study is to estimate the distribution of various variants of SARS-CoV-2 in Moscow city and the Moscow Region. Materials and methods. 227 SARS-CoV-2 sequences were used for analysis. Isolation of the SARS-CoV-2 virus was performed on Vero E6 cell culture. Sequencing was performed by the Sanger method. Bioinformatic analysis was carried out using software packages: MAFFT, IQ-TREE v1.6.12, jModelTest 2.1.7, Nextstrain, Auspice v2.34. Results. As a result of phylogenetic analysis, we have identified the main variants of the virus circulating in Russia that have been of concern throughout the existence of the pandemic, namely: variant B.1.1.7, which accounted for 30% (9/30), AY.122, which accounted for 16.7% (5/30), BA.1.1 with 20% (6/30) and B.1.1 with 33.3% (10/30). When examining Moscow samples for the presence of mutations in SARS-CoV-2 structural proteins of different genovariants, a significant percentage of the most common substitutions was recorded: S protein D614G (86.7%), P681H/R (63.3%), E protein T9I (20.0%); M protein I82T (30.0%), D3G (20.0%), Q19E (20.0%) and finally N protein R203K/M (90.0%), G204R/P (73.3 %). Conclusion. The study of the frequency and impact of mutations, as well as the analysis of the predominant variants of the virus are important for the development and improvement of vaccines for the prevention of COVID-19. Therefore, ongoing molecular epidemiological studies are needed, as these data provide important information about changes in the genome of circulating SARS-CoV-2 variants.

The reaction between the 1,4-dioxane derivative of the closo -decaborate anion [2-B 10 H 9 O(CH 2 ) 4 O] – with cyanide, hydrophthalate, and hydroiminoacetate ions has been studied. Alkali metal salts (K, Na, and Cs) of the closo -decaborate anion derivatives with pendant groups –NHCH 2 CH 2 NH 2 -, –OOC( o -C 6 H 4 )COOH-, –OOCCH 2 NHCH 2 COOH-, –OCH 2 CH 2 OH-, –CN-, –SCN-, and –SH- have been isolated. All compounds have been shown to have extremely low cytotoxicity (CT 50 ~ 1000 μg/mL). It has been found that compounds Na 2 [B 10 H 9 O(CH 2 ) 2 O(CH 2 ) 2 SCN] and Na 2 [B 10 H 9 O(CH 2 ) 2 O(CH 2 ) 2 CN] exhibit activity and selectivity in vitro against the modern strain of SARS-CoV-2 coronavirus (IC 50 312 and 625 μg/mL, respectively). In relation to influenza A virus and rabies virus, the compounds show weak antiviral activity at high concentrations (1250 μg/mL), i.e. show no selective effect on the reproduction of these viruses.

It has recently been shown that the titer of the SARS-CoV-2 virus decreases in a cell culture when the cell suspension is irradiated with electromagnetic waves at a frequency of 95 GHz. We assumed that a frequency range in the gigahertz and sub-terahertz ranges was one of the key aspects in the “tuning” of flickering dipoles in the dispersion interaction process of the surfaces of supramolecular structures. To verify this assumption, the intrinsic thermal radio emission in the gigahertz range of the following nanoparticles was studied: virus-like particles (VLP) of SARS-CoV-2 and rotavirus A, monoclonal antibodies to various RBD epitopes of SARS-CoV-2, interferon-α, antibodies to interferon-γ, humic–fulvic acids, and silver proteinate. At 37 °C or when activated by light with λ = 412 nm, these particles all demonstrated an increased (by two orders of magnitude compared to the background) level of electromagnetic radiation in the microwave range. The thermal radio emission flux density specifically depended on the type of nanoparticles, their concentration, and the method of their activation. The thermal radio emission flux density was capable of reaching 20 μW/(m2 sr). The thermal radio emission significantly exceeded the background only for nanoparticles with a complex surface shape (nonconvex polyhedra), while the thermal radio emission from spherical nanoparticles (latex spheres, serum albumin, and micelles) did not differ from the background. The spectral range of the emission apparently exceeded the frequencies of the Ka band (above 30 GHz). It was assumed that the complex shape of the nanoparticles contributed to the formation of temporary dipoles which, at a distance of up to 100 nm and due to the formation of an ultrahigh strength field, led to the formation of plasma-like surface regions that acted as emitters in the millimeter range. Such a mechanism makes it possible to explain many phenomena of the biological activity of nanoparticles, including the antibacterial properties of surfaces.

Introduction. In Russia, almost half of the cases of acute intestinal infections of established etiology in 2022 are due to rotavirus infection (RVI). There is no specific treatment for rotavirus gastroenteritis. There is a need to develop modern, effective and safe vaccines to combat rotavirus infection that are not capable of multiplying (replicating) in the body of the vaccinated person. A promising approach is to create vaccines based on virus-like particles (VLPs). Objective. Study of the safety and immunogenicity of a vaccine against rotavirus infection based on virus-like particles of human rotavirus A in newborn minipigs with multiple intramuscular administration. Materials and methods. Newborn minipigs were used as an animal model in this study. The safety of the tested vaccine was assessed based on thermometry data, clinical examination, body weight gain, clinical and biochemical blood parameters, as well as necropsy and histological examination. When studying the immunogenic properties of the Gam-VLP-rota vaccine in doses of 30 and 120 µg, the cellular, humoral and secretory immune response was studied. Results. The results of assessing the general condition of animals during the immunization period, data from clinical, laboratory and pathomorphological studies indicate the safety of the vaccine against human rotavirus infection based on VLP (Gam-VLP-rota) when administered three times intramuscularly. Good local tolerance of the tested vaccine was demonstrated. The results of the assessment of humoral immunity indicate the formation of a stable immune response after three-time immunization with Gam-VLP-rota, stimulation of the production of antigen-specific IgG antibodies and their functional activity to neutralize human rotavirus A. It was shown that following the triple immunization with the minimum tested concentration of 30 µg/dose, animals developed a cell-mediated immune response. The results of the IgA titer in blood serum and intestinal lavages indicate the formation of both a systemic immunological response and the formation of specific secretory immunity to human rotavirus A. Conclusion. Thus, three-time intramuscular immunization of minipigs with the Gam-VLP-rota vaccine forms stable protective humoral and cellular immunity in experimental animals. Evaluated vaccine is safe and has good local tolerability.

The reaction between the 1,4-dioxane derivative of the closo-decaborate anion [2-B10H9O(CH2)4O]– with cyanide, hydrophthalate, and hydroiminoacetate ions has been studied. Alkali metal salts (K, Na, and Cs) of the closo-decaborate anion derivatives with pendant groups –NHCH2CH2NH2-, –OOC(o-C6H4)COOH-, –OOCCH2NHCH2COOH-, –OCH2CH2OH-, –CN-, –SCN-, and –SH- have been isolated. All compounds have been shown to have extremely low cytotoxicity (CT50 ~ 1000 μg/mL). It has been found that compounds Na2[B10H9O(CH2)2O(CH2)2SCN] and Na2[B10H9O(CH2)2O(CH2)2CN] exhibit activity and selectivity in vitro against the modern strain of SARS-CoV-2 coronavirus (IC50 312 and 625 μg/mL, respectively). In relation to influenza A virus and rabies virus, the compounds show weak antiviral activity at high concentrations (1250 μg/mL), i.e. show no selective effect on the reproduction of these viruses.

The continuous emergence of new pathogens and the evolution of microbial drug resistance make it absolutely necessary to develop innovative, effective vaccination strategies. Use of nasal vaccination can increase convenience, safety, cause both local and systemic immune reactions. Intranasal administration nevertheless has a number of shortcomings that can be overcome by using the latest achievements of pharmaceutical science. One of the aspects of such solution may be the use of systems for the production of intranasal vaccines in situ polymer compositions that provide a directed sol-gel transition controlled by the physiological conditions of the nasal cavity. At the same time, the gelation of the administered dose in contact with the nasal mucosa involves prolonged exposure of the drug at the injection site, greater mucoadhesion, counteraction to mucociliary clearance, modified and more complete release. A number of both foreign and domestic manufacturers produces polymers such as chitosan, gums, polyoxyethylene and polyoxypropylene block copolymers (poloxamers, proxanols), carbomers. For effective pharmaceutical development of new intranasal IBD delivery systems corresponding to the QbD concept, not only the knowledge of the range of excipients is necessary, but also simple, accessible, and reproducible methods for determining indicators that define the critical parameters of such delivery systems. In accordance with the conducted scientific search, the main indicators of standardization of in situ intranasal systems were identified: temperature and time of gel formation, gel strength, rheological characteristics, mucoadhesion, release, nasal mucociliary clearance time.

Introduction. Variants of influenza virus A/H7 have the same high pandemic potential as A/H5. However, the information about the antigenic structure of H7 hemagglutinin (НА) is considerably inferior in quantitative terms to similar data for H5 НА.The aims of the study were development and characterization of the monoclonal antibodies (MAbs) panel for HA subtype H7 of the influenza A virus.Material and methods. Viruses were accumulated in 10-day-old chicken embryos. Purification and concentration of the virus, determination of protein concentration, preparation of MAbs and ascitic fluids, hemagglutination and hemagglutination inhibition (HI) tests, assessment of antibodies’ activity in indirect enzyme-linked immunosorbent assay (ELISA), as well as determination of MAbs isotypes and neutralization reaction (NR) were carried out by standard methods.Results. The obtained MAbs to А/mallard/Netherlands/12/2000 (H7N3) strain were studied in HI test with a set of strains of different years of isolation belonging to different evolutionary groups. MAbs had a reduced reactivity compared to the immunogen-virus for all the studied strains. Cross-interaction of MAbs 9E11 and 9G12 in HI test with influenza A/H15 virus has been observed.Discussion. Influenza A agent with H7 HA variant could serve as a potential cause of a future pandemic. Development of the MAbs panel for subtype H7 HA is an urgent task for both veterinary medicine and public health.Conclusion. The obtained MAbs can be used not only for epitope mapping of the H7 HA molecule (currently insufficiently studied) and as reagents for diagnostic assays, but also for determining common («universal») epitopes in HA of different strains of this subtype.

Group A rotavirus (RVA) infection is the leading cause of hospitalization of children under 5 years old, presenting with symptoms of acute gastroenteritis. The aim of our study was to explore the genetic diversity of RVA among patients admitted to Moscow Infectious Disease Clinical Hospital No. 1 with symptoms of acute gastroenteritis. A total of 653 samples were collected from May 2019 through March 2020. Out of them, 135 (20.67%) fecal samples were found to be positive for rotavirus antigen by ELISA. RT-PCR detected rotavirus RNA in 80 samples. Seven G-genotypes (G1, G2, G3, G4, G8, G9, and G12) and three P-genotypes (P[8], P[4], and P[6]) formed 9 different combinations. The most common combination was G9P[8]. However, for the first time in Moscow, the combination G3P[8] took second place. Moreover, all detected viruses of this combination belonged to Equine-like G3P[8] viruses that had never been detected in Russia before. The genotype G8P[8] and G9P[4] rotaviruses were also detected in Moscow for the first time. Among the studied rotaviruses, there were equal proportions of Wa and DS-1-like strains; previous studies showed that Wa-like strains accounted for the largest proportion of rotaviruses in Russia.

Due to the emergence of a new coronavirus infection COVID-19, scientists around the world are actively working on a vaccine against the SARS-CoV-2 coronavirus. At the same time, it is possible that existing medications can help in the fight against this disease. The local antiseptic drug benzidamine hydrochloride in the early stages of illness can prevent the virus from entering the lower respiratory tract and potentially reduce the severe illness associated with pneumonia and, as a result, reduce COVID19-related hospitalizations, which can significantly reduce the burden on the health care system. The aim : to evaluate the antiviral activity of benzidamine hydrochloride against SARS-CoV-2 in vitro. Material and methods . Antiviral properties of benzidamine hydrochloride were studied in vitro in non-toxic concentrations on monolayer of Vero-E6 cells infected with pandemic strain of SARS-CoV-2 coronavirus in treatment and prophylactic scheme of the compound and virus administration. Results . Benzidamine hydrochloride has antiviral activity (15,0 mcg/ml), the efficiency of its antiviral action is directly proportional to the concentration of the substance. Conclusions . Taking into account very limited range of antiviral drugs with direct action on SARS-CoV-2 virus, the studied preparation can be used in complex therapy at early stages of the disease, which can prevent virus penetration into lower respiratory tract and potentially reduce the number of complications.

This work presents the results of a comprehensive physico-chemical and biological study of hu-mic substances samples – an extract of humic and fulvic acids. The performed loss on drying test showed a 22 times different dry matter content between EHS and FA. The morphology and dis-tribution of particles in the dry residue of the samples assessed using the methods of optical and digital microscopy demonstrated differences in the qualitative features of the microstructures of their surfaces and granulometries. Shimadzu X-ray fluorescence spectrometry revealed Si (8.1 and 1.7%), P (33.5 and 2.7%), S (4.3 and 59.5%), K (1.35 and 2.5%), Ca (10.9 and 3.2%), Mn (0.27 and 0.06%), Fe (11 and 0.05%), Cu (0.16 and 0.45%), Zn (0.06 and 0.02%) in the dry residues of the EHS and FA samples, respectively. A high intensity of the X-ray fluorescence signal for Fe atoms in the EHS sample was demonstrated. The FT-IR spectra for EHS and FA are characterized by simi-lar vibration frequencies that are characteristic of the chromone derivatives (1-benzopyran-4-one). The UV absorption spectrum is characterized by max = 281 nm for FA. The EHS solution showed a fluorescence maximum at em = 560 nm at ex = 280 nm. Using the DLS method, nanoparticles of 1 nm and 200 nm were detected in EHS and FA diluted solutions, which are likely to condition the biochemical and physical properties of humic acids. Using the Spiro-tox-test method, the absence of the toxic effect of humic acids on the cell model of ciliates Sp. am-bigua was established. When the cell model was incubated in a solution of a toxicant of the fluo-roquinolone group, a decrease in toxicity was demonstrated when diluted with the EHS solu-tion. The results of the study of the antiviral activity of EHS and FA showed that the study ob-jects in the culture of Vero-E6 cells, in doses non-toxic to cells, suppress the reproduction of the SARS-CoV-2 virus both in the study of the virucidal effect and in the study of the antiviral activ-ity according to the therapeutic and prophylactic model scheme of injection. The results obtained suggest that standardized drugs based on humic acids may open up new perspectives in their biomedical application as antiviral drugs.