Problems of Virology

Mumps is an infectious disease controlled by specific vaccine prophylaxis. To date, its social and epidemiological significance remains high. This is evidenced by the process of developing and implementing into the health care practices of many countries a set of measures for surveillance of mumps. In the Russian Federation, the National Program «Elimination of measles and rubella and achievement of sporadic morbidity with epidemic mumps in the Russian Federation (2021–2025)» and the national plan for its implementation were adopted in 2021. The basis for the adoption of these documents was the development of the domestic trivalent vaccine for the prevention of measles, rubella and mumps, Vaktrivir, and the start of its clinical application. The availability of this vaccine will make the epidemiological surveillance of mumps to be a part of the existing system of appropriate measures for measles and rubella. The fulfillment of this set of tasks involves the study of the molecular epidemiology of the mumps virus (MuV) with possible subsequent implementation of its methodology into the surveillance actions. In this connection, this work was aimed at presenting the data on global genetic diversity of MuV as well as its genotyping methods in a systematized form. The analysis of MuV global genetic diversity in different years will be the starting point in the subsequent development of approach to monitoring virus strains circulating in the Russian Federation.

By the end of 2021, about 200 studies on the effect of interferons (IFNs) on the incidence and course of the new coronavirus infection COVID-19 (Coronaviridae: Coronavirinae: Betacoronavirus: Sarbecovirus) have been reported worldwide, with the number of such studies steadily increasing. This review discusses the main issues of the use of IFN drugs in this disease. The literature search was carried out in the PubMed, Scopus, Cochrane Library, Web of Science, RSCI databases, as well as in the Google Scholar preprint database using the available search queries «MeSH for coronavirus», «SARS-CoV-2», «IFN drugs», and «COVID-19». Interferon therapy is indicated for early administration (within the first 5 days of patient admission) in cases of mild to moderate COVID-19 to take advantage of the narrow therapeutic window of IFNs action. Control and suppression of viral replication requires therapy with IFNs and other effective antiviral agents that inhibit the reproduction of SARS-CoV-2 and induce several interferon-stimulated genes (ISG). Type I IFNs (IFN-I) exhibit potent pro-inflammatory properties and activate a wide variety of different cell types that respond to IFNs stimulation and pathogen entry. IFN-III confer local mucosal antiviral immunity without inducing the strong systemic pro-inflammatory responses associated with IFN-I. The use of IFNs drugs in the therapy of new coronavirus infection requires a cautious and differentiated approach, because in severe cases they can aggravate viral pathogenesis by causing excessive intensity of inflammatory reactions. The unique biological properties of substances of this class allow us to consider them as therapeutic agents with significant potential for use in patients with COVID-19.

Introduction. Rubella is currently an infection controlled by specific prophylaxis. Not only the right vaccine prophylaxis strategy and tactics, but also the use of effective and safe vaccine preparations is crucial for the elimination of this disease.

The aim of the investigation was to study the morphological and pathogenetic patterns of changes developing in the central nervous system (CNS) and internal organs of monkeys (Haplorhini) during intracerebral inoculation with 2 strains of rubella virus (Matonaviridae: Rubivirus: Rubella virus) (RV): highly attenuated Orlov-B, and low attenuated Orlov-14.

Material and methods. In the experiments, seronegative rhesus macaque monkeys (Macaca mulatta) weighing 3.3–5.1 kg (n = 7) were used. Neurovirulence of the strains was determined by a complex of clinical, pathomorphological, and virological methods.

Results and discussion. It was found that during attenuation, the Orlov-B strain lost the ability to replicate in CNS cells and induce moderate/expressed specific changes in them, as well as to overcome the blood-brain barrier and cause the damage of sensitive organs and tissues. This fact indicates a low level of residual neurovirulence of the vaccine strain.

Conclusion. The results obtained in this study regarding the clinical symptoms of CNS lesions and the nature of the pathological process in its tissues in experimental animals can be significant for the improvement of safety control of live rubella vaccines. These data indicate that the Orlov-B strain can be considered as a candidate strain for further study on the development of a rubella vaccine based on the domestic vaccine strain.

Introduction. The causative agent of African swine fever (Asfarviridae: Asfivirus: African swine fever virus) (ASF) is a double-stranded DNA virus of 175–215 nm. To date, 24 of its genotypes are known. Clustering of ASF genotype II isolates is carried out by examining a limited number of selected genome markers. Despite the relatively high rate of mutations in the genome of this infectious agent compared to other DNA viruses, the number of known genome molecular markers for genotype II isolates is still insufficient for detailed subclustering. The aims of this work were the comparative analysis of ASFV/Zabaykali/WB-5314/2020 virus isolate and determination of additional molecular markers which can be used for clustering of viral genotype II sequences. Material and methods. ASF virus isolate ASFV/Zabaykali/WB-5314/2020 was used to extract genomic DNA (gDNA). Sequencing libraries were constructed using the Nextera XT DNA library prepare kit (Illumina, USA) using the methodology of the next generation sequencing (NGS). Results. The genome length was 189,380 bp, and the number of open reading frames (ORFs) was 189. In comparison with the genome of reference isolate Georgia 2007/1, 33 single nucleotide polymorphisms (SNPs) were identified, of which 13 were localized in the intergenic region, 10 resulted to the changes in the amino acid sequences of the encoded proteins, and 10 affected the ORF of ASF virus genes. Discussion. When analyzing intergenic regions, the ASFV/Zabaykali/WB-5314/2020 isolate is grouped separately from a number of isolates from Poland and three isolates from People’s Republic of China (PRC), since it does not harbor additional tandem repeat sequence (TRS). At the same time, the construction of a phylogenetic tree based on DP60R gene sequencing relates ASFV/Zabaykali/WB-5314/2020 to isolates from PRC and Poland. Moreover, phylogenetic analysis of full-genome sequences confirmed previous studies on the grouping of viruses of genotype II, and as for the studied isolate, it was grouped with the variants from China. Conclusion. A new variable region was identified, the DP60R gene, clustering for which gave a result similar to the analysis of full-length genomes. Probably, further study of the distribution of ASF virus isolates by groups based on the analysis of this gene sequences will reveal its significance for studying the evolution of the virus and its spread.

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