Problems of Virology

The review presents current data on the chiropterofauna inhabiting Western Siberia and the south of the European part of Russia. A general description of the genus of lyssaviruses and the family of coronaviruses is given. The potential for virus carriage in relation to lyssaviruses and coronaviruses in bat populations of two geographically distant regions is considered.

Introduction. Chemotherapy of HIV infection remains the only means of treating the disease. The process of development new and improving previously developed drugs is therefore considered a priority. One of the preclinical stage of drug efficacy testing is research in the virus-cell model system in vitro.

The aim. To evaluate the antiviral efficacy of nucleoside reverse transcriptase inhibitors (NRTIs) 6HP and 3TC during HIV-1 replication in the neoplastic MT-4 cell line.

Materials and methods. Two variants of the CD4⁺ T-lymphocyte MT-4 cell line (MT-4/1 and MT-4/2) transformed by Human T-lymphotropic virus type 1 (Retroviridae: Orthoretrovirinae: Deltaretrovirus: HTLV-1), with different levels of HIV-1 replication were used. Drugs ammonium-3’-azido-3’-deoxythymidine-5’-carbomoylphosphonat (6HP) and 2’,3’-dideoxy-3’-thiacytidine (3TC) were used to suppress the virus.

Results and discussion. The replication activity of HIV-1 was observed to be higher in the MT-4/2 line than in the MT-4/1 line for different strains of the virus. The use of each of the substances separately showed a more significant inhibition of viral activity in MT-4/1 than in MT-4/2 cells. When used together, the inhibition level was almost the same in all cases and ranged from 87‒96% for the MT-4/1 line and 83‒89% for the MT-4/2 line. High efficacy was observed when using lower concentrations of drugs compared to individual use.

Conclusion. The combined use of NRTIs 6НР and 3TС is promising for the treatment of HIV-infected patients at different stages of infection and with different levels of viral load.

Introduction. The rapid spread of coronavirus infection COVID-19 among the population of many countries around the world has contributed to the emergence of many genetic variants of SARS-CoV-2. Compared to previous coronavirus variants, the new Omicron variants have shown a noticeable degree of mutation. Virus inactivation is one of the most important steps in the development of inactivated vaccines. The chemical inactivation agents currently used are β-propiolactone and formaldehyde, but there is no uniform standard for designing and specifying the inactivation process.

Objective. Evaluation and comparison of the effectiveness of chemical inactivation of two agents, formaldehyde and β-propiolactone against immunogenicity of the Omicron variant of the SARS-CoV-2 virus.

Materials and methods. Nasopharyngeal swabs were used to obtain the SARS-CoV-2 Omicron variant virus. Vero cell culture was used to isolate, reproduce, titrate the virus, and perform a neutralization reaction. The kinetics of studying the inactivation of the virus by chemical agents such as formaldehyde and β-propiolactone was carried out.

Results. Studies have been conducted to comparatively evaluate the effectiveness of chemical agents used to inactivate the SARS-CoV-2 virus of the Omicron variant, planned for use in the production of an inactivated whole-virion vaccine. Formaldehyde and β-propiolactone were used as inactivation agents in concentrations of 0.05, 0.1, 0.5% of the total volume of the virus suspension. It has been established that complete inactivation of the virus by formaldehyde in the concentrations used at a temperature of 37 °C occurs within up to 2 hours, and when using beta-propiolactone, within up to 12 hours.

Conclusion. Inactivated virus samples have different antigenic activity depending on the concentration of the inactivation agents used. The most pronounced antigenic activity is manifested in samples of the pathogen that were treated with an inactivation agent at a mild concentration of 0.05%. Increasing the concentration of inactivation agent by 5 or more times leads to a significant decrease in the antigenicity of the SARS-CoV-2 virus. With the inactivation modes used, the loss of biological activity of the virus occurs faster and antigenicity is retained largely when treated with formaldehyde.

Introduction. The lack of data on the whole-genome sequences of African swine fever virus (ASFV) variants circulating on the territory of the left bank of the Dnieper River complicates the understanding of the molecular evolution of the virus and the character of the epidemic process development in Russia and Ukraine. Understanding the genetic divergence and phylogenetic relatedness of isolates can largely adjust the strategy of general and specific prevention of the disease.

The aim of the study – search and description of unique mutations (deletions/insertions/substitutions) in isolates collected from domestic pigs in Donetsk, Luhansk and Zaporozhye regions in 2023; determination of relatedness and level of homology with reference strains of ASFV genotype II; sub-genotyping and clustering of isolates based on whole-genome analysis.

Materials and methods. The samples used were a culture suspension of porcine bone marrow (PBM) cells containing ASFV isolates obtained from pathologic material from domestic pig carcasses. Genomic DNA was prepared by purification and concentration of virus followed by phenol-chloroform extraction of total nucleic acid. The high-throughput sequencing process was performed using MGI technology. Consensus sequences were assembled by mapping reads to the reference genome of strain Georgia 2007/1.

Results. All isolates are assigned to genotype II, have a monophyletic origin, are phylogenetically close to the clusters «Europe» (4/5) and «Bryansk 2021» (1/5), and are divergent from the original parental genetic variants that make up the enlarged clades. In addition, numerous substitutions in the loci of the multigene family MGF 110, 505, and 360, encoding virulence proteins, were detected in 4 isolates from Donetsk and Zaporozhye regions.

Conclusion. The phylogeny of the genotype II ASFV, which originated from the reference strain Georgia 2007/1, is shown to be sufficient for isolate differentiation. The presented data are of theoretical and practical importance for domestic and international ASFV surveillance.