Introduction. Epstein–Barr virus (EBV) is a widespread gamma-herpesvirus associated with a number of malignancies, including nasopharyngeal carcinoma and gastric cancer (GC/EBV+). The primary oncogenic protein of EBV is latent membrane protein 1 (LMP1). Genetic variability of the LMP1 protein affects its oncogenic activity and clinical manifestations. Objective. To investigate the optimal threshold value for EBV viral load, determine the correlation between high viral load and the detection of the LMP1 gene in the blood of patients with GC/EBV+, and to identify mutations in the C-terminal domains of the LMP1 gene that may affect protein function. Materials and methods. Total DNA was extracted from 227 blood samples of GC patients. The LMP1 gene was amplified using nested PCR. EBV DNA viral load in blood samples was analyzed by qPCR, followed by receiver operating characteristic (ROC) analysis and interquartile range (IQR) assessment. A selection criterion for positive DNA samples (EBV+) was established based on the mean viral load and ROC threshold. Results. ROC curve analysis and descriptive statistics identified 23 EBV-positive (EBV+) DNA samples, with the following results: AUC (area under the curve) = 0.83, optimal threshold 526.92 copies/reaction, sensitivity 0.69, specificity 0.87, and mean viral load: 513.5 copies/reaction. A statistically significant association was found between detection of the LMP1 gene in the blood and viral load level (χ2 test p = 0.018; Mann–Whitney U test p 0.0001). Additionally, synonymous and nonsynonymous mutations were identified in regions of LMP1 gene coding the C-terminal activating domains (CTAR1 and CTAR2). Conclusion. The findings highlight the heterogeneous molecular nature of EBV-associated gastric cancer, including genetic mutations in the LMP1 gene.

Introduction. The WHO regularly updates influenza vaccine recommendations to maximize their match with circulating strains. Nevertheless, the effectiveness of the influenza A vaccine, specifically its H3N2 component, has been low for several seasons. The aim of the study is to develop a mathematical model of cross-immunity based on the array of published WHO hemagglutination inhibition assay (HAI) data. Materials and methods. In this study, a mathematical model was proposed, based on finding, using regression analysis, the dependence of HAI titers on substitutions in antigenic sites of sequences. The computer program we developed can process data (GISAID, NCBI, etc.) and create real-time databases according to the set tasks. Results. Based on our research, an additional antigenic site F was identified. The difference in 1.6 times the adjusted R2, on subsets of viruses grown in cell culture and grown in chicken embryos, demonstrates the validity of our decision to divide the original data array by passage histories. We have introduced the concept of a degree of homology between two arbitrary strains, which takes the value of a function depending on the Hamming distance, and it has been shown that the regression results significantly depend on the choice of function. The provided analysis showed that the most significant antigenic sites are A, B, and E. The obtained results on predicted HAI titers showed a good enough result, comparable to similar work by our colleagues. Conclusion. The proposed method could serve as a useful tool for future forecasts, with further study to confirm its sustainability.

The study of the mechanisms of transmission of the SARS-CoV-2 virus is the basis for building a strategy for anti-epidemic measures in the context of the COVID-19 pandemic. Understanding in what time frame a patient can spread SARS-CoV-2 is just as important as knowing the transmission mechanisms themselves. This information is necessary to develop effective measures to prevent infection by breaking the chains of transmission of the virus. The aim of the work is to identify the infectious SARS-CoV-2 virus in patient samples in the course of the disease and to determine the duration of virus shedding in patients with varying severity of COVID-19. In patients included in the study, biomaterial (nasopharyngeal swabs) was subjected to analysis by quantitative RT-PCR and virological determination of infectivity of the virus. We have determined the timeframe of maintaining the infectivity of the virus in patients hospitalized with severe and moderate COVID-19. Based on the results of the study, we made an analysis of the relationship between the amount of detected SARS-CoV-2 RNA and the infectivity of the virus in vitro in patients with COVID-19. The median time of the infectious virus shedding was 8 days. In addition, a comparative analysis of different protocols for the detection of the viral RNA in relation to the identification of the infectious virus was carried out. The obtained data make it possible to assess the dynamics of SARS-CoV-2 detection and viral load in patients with COVID-19 and indicate the significance of these parameters for the subsequent spread of the virus and the organization of preventive measures.

Zika virus (ZIKV) infection during pregnancy can result in severe outcomes for both the pregnant woman and the developing fetus. The objective of this study was to investigate the prevalence of Zika virus infection among pregnant women who sought healthcare services at Ahmadu Bello University Teaching Hospital. Serum samples were collected and analyzed using Enzyme Linked Immunoassay and RT-qPCR methods, while a structured questionnaire was used to gather relevant information about the participants. The results showed that 53 out of the 180 pregnant women tested positive for Anti-Zika IgM antibodies, which represents a 29.4% prevalence rate. Subsequent RT-qPCR analysis found that only 6 out of the 53 positive samples contained Zika virus RNA. Fever and headache were the most commonly reported symptoms related to the infection. These findings indicate a potential outbreak of Zika fever in Northern Nigeria emphasizing the importance for pregnant women to take precautions to avoid getting infected.

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. 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. 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 %). 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 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.

Outbreaks of infectious diseases seriously hinder the preservation and increase of the number of small ruminants. Such infections include sheep pox virus (SPPV). According to the OIE data of 2021, SPP outbreaks were registered in countries such as Turkey, Israel, China, Maldives, Mongolia, Thailand, Russia, Algeria, Kenya, and in 2019 in Mangistau and Atyrau regions. In Kazakhstan annually conducts routine immunization of sheep at risk with a live attenuated vaccine produced by RIBSP. The object of the study was the vaccine strain of NISHI and the virulent strain A of the sheep pox virus. The virus was propagated in Vero cells. To determine the harmlessness and immunogenicity, sheep of the Kazakh fine-wool breed aged from 6 to 12 months were used. Virological, serological and immunobiological methods were used in the study. The results of the adaptation of the NISHI strain of SPPV to the Vero cell line are presented. Five passages in Vero cells resulted to the adaptation of the NISHI strain with the manifestation of a cytopathogenic effect specific to SPPV with a titer of 6.50 lg TCD50/ml. Following immunization, the formation of immunity was observed in animals on day 7 with an average protective titer 1.8 log2, which increased by day 21 to 4.33 log2. It has been established that the NISHI strain of SPPV retains its virological and immunobiological properties during reproduction in a Vero cell line.

Lumpy skin disease (LSD), sheep pox and goat pox are dangerous diseases of domestic ruminants. Representatives of the genus of capripoxviruses are antigenically similar and can be used as a vaccine for three infections, as in the case of representatives of the genus of orthopoxviruses, which includes viruses of smallpox, monkeypox, and cowpox, that all belong to a single family Poxviridae. In this study, the vaccine strain G20-LKV of the goat pox virus and the virulent strain RIBSP2019/K of the LSD virus were used. The experiments were carried out on clinically healthy cattle of the Kazakh White-headed breed, aged six to eight months. Virological and serological research methods were used in the work. All immunized animals that received different doses of the vaccine showed resistance to the infection challenge, without showing any clinical signs of the disease. In animals that received the lowest doses of the vaccine 15,000, 30,000 and 40,000 TCID50, no adverse events, skin and temperature reactions were observed at the injection site. Those vaccinated with high doses of the vaccine had a local reaction in the form of swelling at the site of vaccine administration. Control animals infected with a virulent virus showed clinical signs of the cattle lumpy skin disease . The vaccine, prepared based on the "G20-LKV" strain of the goat virus, is protective for cattle against infection with a virulent LSD virus at immunizing doses from 15,000 to 80,000 TCID50, which are dependent on the LSD epizootic situation in particular region.

Non-polio enteroviruses (NPEVs) are ubiquitous and are one of the main causative agents of viral infections in children. NPEVs most commonly infect newborns and young children, due to their lack of antibodies. In children, clinical manifestations can range from acute febrile illness to severe complications that require hospitalization and lead in some cases to disability or death. NPEV infections can have severe consequences, such as polio-like diseases, serous meningitis, meningoencephalitis, myocarditis, etc. The most promising strategy for preventing such diseases is vaccination. No less than 53 types of NPEVs have been found to circulate in Russia. However, of epidemic importance are the causative agents of exanthemic forms of the disease, aseptic meningitis and myocarditis. At the same time, the frequency of NPEV detection in the constituent entities of the Russian Federation is characterized by uneven distribution and seasonal upsurges. The review discusses the epidemic significance of different types of enteroviruses, including those relevant to the Russian Federation, as well as current technologies used to create enterovirus vaccines for the prevention of serious diseases.

The discovery of the Epstein-Barr virus types (Herpesviridae: Gammaherpesvirinae: Lymphocryptovirus: Human gammaherpesvirus 4) (EBV) - EBV-1 and EBV-2, which have different transforming abilities in vitro, stimulated the study of their prevalence in populations in order to elucidate the relationship with malignant neoplasms.The aims of the work are to study the prevalence of EBV-1 and EBV-2 among representatives of 2 ethnic groups of Russia, Kalmyks and Slavs, sequencing analysis of the LMP1 oncogene in virus isolates, and analysis of the correlation between virus types and the incidence of certain forms of tumors. DNA samples were isolated from the biological material of oral swabs obtained from ethnic Kalmyks of the Republic of Kalmykia (RK) (n = 50) and Slavs, residents of the Moscow Region (MR) (n = 40). DNA samples were used to amplify EBV DNA, followed by determination of its concentration per 1 cell of washout, amplification of the LMP1 oncogene in viral samples, their sequencing, and determination of LMP1 protein variants. It has been established that with the same burden of EBV among representatives of both ethnic groups in the Kalmyk group, the ratio of persons infected with transforming and non-transforming types of the virus was almost the same (EBV-1 - 51%; and EBV-2 - 49%). Meanwhile, in the group of Slavs the transforming EBV-1 type virus dominated (80.6%). The predominance of EBV-1 type in representatives of the Slavs correlated with increased incidence of certain forms of tumors in the population of the MR when compared with similar values in the population of the RK, where both types of the virus were prevalent. Differences between the compared rates of cancer incidence were not statistically significant. Analysis of viral isolates showed a similar set of LMP1 variants in both ethnic groups. In order to establish the influence of EBV types on the incidence of malignant tumors, additional studies involving representatives of various ethnic groups from different geographical regions are needed.