Voprosy virusologii最新文献

Introduction: The World Health Organization considers the values of antibody titers in the hemagglutination inhibition assay as one of the most important criteria for assessing successful vaccination. Mathematical modeling of cross-immunity allows for identification on a real-time basis of new antigenic variants, which is of paramount importance for human health.

Materials and methods: This study uses statistical methods and machine learning techniques from simple to complex: logistic regression model, random forest method, and gradient boosting. The calculations used the AAindex matrices in parallel to the Hamming distance. The calculations were carried out with different types and values of antigenic escape thresholds, on four data sets. The results were compared using common binary classification metrics.

Results: Significant differentiation is shown depending on the data sets used. The best results were demonstrated by all three models for the forecast autumn season of 2022, which were preliminary trained on the February season of the same year (Auroc 0.934; 0.958; 0.956, respectively). The lowest results were obtained for the entire forecast year 2023, they were set up on data from two seasons of 2022 (Aucroc 0.614; 0.658; 0.775). The dependence of the results on the types of thresholds used and their values turned out to be insignificant. The additional use of AAindex matrices did not significantly improve the results of the models without introducing significant deterioration.

Conclusion: More complex models show better results. When developing cross-immunity models, testing on a variety of data sets is important to make strong claims about their prognostic robustness.

Introduction: Varicella zoster virus (VZV) is a type of alpha-herpesvirus that specifically targets the nervous system. The initial infection, typically occurring during childhood, results in varicella (commonly known as chickenpox), after which the virus enters a dormant state in cranial nerve ganglia, dorsal root ganglia, and autonomic ganglia throughout the entire neuroaxis.

Aim of the study: Molecular and genetic studies of viruses are an important tool for virus development and identifying viral treatments to combat the diseases. The aim of the study was to determine the whole ORF4 sequence of the local VZV strains for phylogenetic analysis to determine the variability in the viral sequence.

Material and methods: Ten samples of VZV DNA were subjected to the sequencing of the whole ORF4 region following identification using the PCR method.

Results: Sequences from five samples have been successfully analyzed. All clinical strains were discovered to possess a genome with a length of 124,884 base pairs. The sequences exhibited the occurrence of two distinct mutations, one being a transversion and the other a transition, with the latter resulting in an alteration of the amino acid. A phylogenetic tree was constructed using the maximum likelihood method based on the sequences of five nucleotide sequences from clinical samples and nine reference VZV strains. The tree displayed the evolutionary distances between these sequences. The analysis of the phylogenetic tree revealed the presence of five primary clades, with four of them originating from India (isolates S1, S2, S4, S5), while S3 exhibited similarity to a strain from the United Kingdom.

Introduction: Rotavirus infection is the major cause of severe dehydrating diarrhea requiring hospitalization in young children worldwide. Due to their segmented genome, rotaviruses are capable of gene reassortment, which makes the emergence and spread of genetically novel strains possible. The purpose of this study was to search for unusual rotaviruses circulating in Nizhny Novgorod in 2021‒2023 and their molecular genetic characterization based on all genome segments.

Materials and methods: Rotavirus-positive stool samples of children were examined by PCR genotyping and electrophoresis in PAAG. cDNA fragments of each of the 11 genes (VP1‒VP4, VP6, VP7, NSP1‒NSP5), 570 to 850 nucleotide pairs in length were sequenced for the selected strains. The phylogenetic analysis was performed in the MEGA X program.

Results: In the study period 2021‒2023, 11 G[P] combinations with a predominance of G3P[8] (59.5%) were identified. Six atypical Rotavirus А (RVA) strains were identified: 2 strains of the G2P[4] genotype (G2-P[4]-I2-R2-C2-M2-A3-N2-T3-E2-H3, G2-P[4]-I2-R2-C2-M2-A3-N2-T3-E3-H2) and 4 G3P[9] strains (all strains had the genotype G3-P[9]-I2-R2-C2-M2-A3-N2-T3-E3-H3). Phylogenetic analysis based on all genes showed an evolutionary relationship between rotaviruses similar to rotaviruses of cats and dogs (BA222-like) and unusual strains of the G2P[4] genotype, for which a mixed combination of genotypes was identified and characterized for the first time.

Discussion: The results obtained expand the understanding of the diversity of reassortant RVAs, as well as complement the data on the genotypic structure of the rotavirus population in Nizhny Novgorod.

Conclusion: The wide genetic diversity of reassortant RVA can help rotaviruses overcome the immunological pressure provided by natural and vaccine-induced immunity. In this regard, to control the emergence of new variants and assess changes in the virulence of rotaviruses after reassortment processes, continuous molecular monitoring for circulating RVA is necessary.

Relevance: Influenza A virus is characterized by a segmented single-stranded RNA genome. Such organization of the virus genome determines the possibility of reassortment, which can lead to the emergence of new virus variants. The main natural reservoir of most influenza A virus subtypes are wild waterfowl. Seasonal migrations gather waterfowl from all major migration routes to nesting areas near the northern and southern polar circles. This makes intercontinental spread of influenza A viruses possible. Objective ‒ to conduct molecular genetic monitoring and study the phylogenetic relationships of influenza A virus variants circulating in Antarctica in 2023.

Materials and methods: We studied 84 samples of biological material obtained from birds and marine mammals in April‒May 2023 in coastal areas of Antarctica. For 3 samples, sequencing was performed on the Miseq, Illumina platform and phylogenetic analysis of the obtained nucleotide sequences of the influenza A virus genomes was performed.

Results: The circulation of avian influenza virus in the Antarctic region was confirmed. Heterogeneity of the pool of circulating variants of the influenza A virus (H3N8, H1N1) was revealed. Full-length genomes of the avian influenza virus were sequenced and posted in the GISAID database (EPI_ISL_19032103, 19174530, 19174467).

Conclusion: The study of the genetic diversity of influenza A viruses circulating in the polar regions of the Earth and the identification of the conditions for the emergence of new genetic variants is a relevant task for the development of measures to prevent biological threats.

Introduction: The persistence of immune dysfunction during therapy has serious consequences for the health of HIV-infected people. Therefore, an important direction is the search for drugs that can reduce the inflammatory potential of the immune system and serve as an additional component of antiviral therapy. Aim ‒ to study the effect of the immunomodulatory drug Sodium deoxyribonucleate with iron complex (DNA-Na-Fe) on the expression of activation markers in MT-4 cells infected with HIV-1.

Materials and methods: Expression levels of CD4, CD28, CD38, CD62L and HLA-DR proteins on the plasma membrane were measured in cells. To assess viral activity, the p24 protein was quantified by ELISA.

Results and discussion: The two cell variants with different replicative activity were analyzed. Control cells, cells with DNA-Na-Fe, infected cells and infected cells with DNA-Na-Fe were tested. Based on the results obtained, it can be concluded that antiviral activity of the drug in MT-4 cells infected with HIV-1 is associated with immunomodulatory activity that enhances the expression of membrane proteins CD4, CD28, CD38 and CD62L. Diversity in the effect of DNA-Na-Fe on the studied surface proteins expression in two cell lines indicates that they depend on the characteristics of the combined molecular biological processes occurring in cells. And the increased effects observed in a system with changes in replicative activity assumes its active participation in virus replication at the stages of virus penetration and budding.

Conclusion: Studies have shown that DNA-Na-Fe has antiviral and immunomodulatory activity.

Objective: The aim of this study was to identify the molecular prevalence of high-risk HPV infection and the distribution of genotypes present in normal cytology, as well as to determine the vaccination status of our study population.

Methods: 110 cervical samples were taken from individuals, and 1 ml of each sample was added to the Xpert HPV cartridge in the sample compartment before it was placed in the Cepheid GeneXpert system. Detection was performed simultaneously via amplification of the E6 and E7 genes in five fluorescent channels (HPV16, HPV18/45, HPV31/33/35/52/58, HPV51/59, and HPV39/56/66/68a).

Results: 36/110 (33%) of all samples tested were positive for HPV DNA. The predominant genotypes were HPV16 (12.7%) and other pooled HR-HPV types (8.2%). All women who received the Gardasil-9 vaccine (3.6%) had HPV, and infection was associated with travel outside Africa. 96.4% of the screened individuals had not received any HPV vaccine.

Conclusion: Our research confirms a widespread HR-HPV infection in our population and extends the importance of studies on the molecular prevalence of HPV, particularly in women with normal cytology and apparent good health, in view of the cruel lack of public awareness of HPV infections.

Introduction: COVID-19 is strongly linked to cardiovascular disease, with direct myocardial injury and systemic inflammation as common mechanisms. Pre-existing or infection-induced cardiovascular disease worsens the outcomes for COVID-19 patients.

Materials and methods: To estimate the serum electrolytes (Na⁺, K⁺, Ca⁺⁺, Zn) and vitamin D₃, the study depended on ichroma ii device for Vitamin D₃ and Chemistry Analyzer for electrolytes in patient samples.

Results: A study was conducted on 192 individuals diagnosed with COVID-19, including 35 critical cases, 53 severe cases, 54 moderate cases, and 50 individuals in a control group. The age group with the highest prevalence of infection was between 50‒69 years, while the lowest prevalence was observed in those under 30 years. The study found significant decreases in calcium, potassium, sodium, zinc, and vitamin D₃ levels among COVID-19 patients compared to the control group. Zinc and vitamin D₃ levels showed a significant correlation with sex, with males experiencing a decline in zinc levels and females having lower vitamin D₃ levels. The concentration of calcium, sodium, and zinc showed a negative correlation with age, with older patients having the lowest levels. COVID-19 patients with chronic cardiac issues and high blood pressure exhibited the lowest levels of these markers. The severity of the disease also had a detrimental impact on electrolyte levels, zinc, and vitamin D₃, with critical cases showing the lowest levels. The complications such as heart failure were associated with lower levels of potassium, sodium, and zinc.

Conclusion: In conclusion, the study revealed significant associations between COVID-19 and decreased electrolyte levels, zinc, and vitamin D₃. Sex and age were found to be correlated with these markers. Patients with chronic cardiac issues and high blood pressure exhibited the lowest levels of these markers. The severity of the disease was also linked to lower electrolyte levels, zinc, and vitamin D₃. Complications such as heart failure were associated with decreased levels of potassium, sodium, and zinc.

Introduction: Specific prevention of a number of infectious diseases has been introduced into the vaccination schedule. The production of immunoprophylactic drugs, in order to establish standard properties, including safety and specific effectiveness, requires strict adherence to manufacturing regulations, and the reliability of the results obtained requires monitoring of these parameters. The specific effectiveness of vaccine preparations is standardized according to the indicators of stimulation of specific antibody response formed in the body of vaccinated model biological objects.

Objective: Determination of the immune reactivity of white mice to vaccination with the QazVac vaccine to establish the possibility of using them as a biological model in assessing the immunogenicity of the vaccine instead of Syrian hamsters.

Materials and methods: The immune reactivity of model animals was assessed by the seroconversion rate, dynamics of antibody titers to the SARS-CoV-2 virus formed in the body after vaccination with the test vaccine. In the case of seropositivity of animals before administration of vaccine or placebo, the level of immune reactivity was calculated by the difference in antibody titers between control and vaccinated animals or by the difference in antibody titers before and after immunization. Specific antibodies were detected and their titer was determined using a neutralization reaction.

Results: The research results showed that the tested biological models had approximately the same immune reactivity to the administration of the QazVac vaccine, confirmed by the level and dynamics of antibody titers. When analyzing the fold increase in antibody titers in comparison to those of control animals, Syrian hamsters were more reactive compared to mice. But SPF white mice were standardized in their lack of the immune reactivity to SARS-CoV-2 virus before the immunization.

Conclusion: The data obtained indicate that the immune reactivity of white mice to the administration of the QazVac vaccine in terms of the rate and dynamics of the formation of virus-neutralizing antibodies is approximately equivalent to the immune reactivity of Syrian hamsters. Before immunization with the vaccine, SPF white mice, in contrast to Syrian hamsters, do not have humoral immunity specific to the SARS-CoV-2 virus. The immune reactivity equivalent to that observed of Syrian hamsters and the absence of antibodies to the SARS-CoV-2 virus at a baseline indicate the superiority of the use of white mice in assessing the immunogenicity of vaccines against COVID-19 and/or obtaining specific factors of humoral immunity.