Vol 68, No 2 (2023)

Introduction. Influenza is one of the most pressing global health problems. Despite the wide range of available anti-influenza drugs, the viral drug resistance is an increasing concern and requires the search for new approaches to overcome it. A promising solution is the development of drugs with action that is based on the inhibition of the activity of cellular genes through RNA interference.

Aim. Evaluation in vivo of the preventive potential of miRNAs directed to the cellular genes FLT4, Nup98 and Nup205 against influenza infection.

Materials and methods. The A/California/7/09 strain of influenza virus (H₁N₁) and BALB/c mice were used in the study. The administration of siRNA and experimental infection of animals were performed intranasally. The results of the experiment were analyzed using molecular genetic and virological methods.

Results. The use of siRNA complexes Nup98.1 and Nup205.1 led to a significant decrease in viral reproduction and concentration of viral RNA on the 3rd day after infection. When two siRNA complexes (Nup98.1 and Nup205.1) were administered simultaneously, a significant decrease in viral titer and concentration of viral RNA was also noted compared with the control groups.

Conclusions. The use of siRNAs in vivo can lead to an antiviral effect when the activity of single or several cellular genes is suppressed. The results indicate that the use of siRNAs targeting the cellular genes whose expression products are involved in viral reproduction is one of the promising methods for the prevention and treatment of not only influenza, but also other respiratory infections.

Introduction. Newcastle disease (ND) is classified as especially dangerous pathogen. Its primary source is an infected or recovered bird. The virus shedding begins just in a day after infection, and virus remains in the body for another 2-4 months after the recovery. The complexity of the final elimination of the causative agent of the disease lies in its ability for long-term preservation in the external environment and the possibility of constant circulation in one complex between groups of birds of different sex and age. Therefore, the main element of protecting birds from ND is immunoprophylaxis that is based on vaccines containing an inactivated ND virus (NDV).

The aim of the work ‒ is to optimize the parameters of inactivation of the NDV actual strain H with formaldehyde at final concentrations of 0.01, 0.025, 0.05, and 0.1% under temperature conditions of 20 ± 2 and 37 ± 0.5 °C.

Materials and methods. We used a virus-containing suspension of the NDV strain H with an initial biological activity of 10.75 lg EID₅₀/cm³ grown by cultivation in 10-day-old developing chick embryos.

Results. On the 16th day after the administration of the tested suspensions of NDV inactivated at different temperatures and concentrations of the inactivant , the geometric mean titers of antibodies to NDV in sera of vaccinated birds were at least 1 : 63 in the hemagglutination inhibition reaction, indicating that the studied inactivated suspensions were antigenically active.

Conclusion. The optimal parameters of the inactivation mode (final concentration, temperature and time of inactivation) of the NDV strain H were established. The inactivation process at 37 ± 0.5 °C with inactivant concentrations of 0.01, 0.025, 0.05, and 0.1% lasts up to 72, 22, 18, and 12 hours, respectively. The inactivation process at 20 ± 2 °C with inactivant concentrations of 0.05 and 0.1% lasts up to 22 and 18 hours, respectively.

Introduction. Pestiviruses and viruses of the Herpesviridae family are widely distributed among different species of ungulates, but the main information about these pathogens is related to their effect on farm animals. Data on detection of bovine viral diarrhea virus (BVDV) and bovine herpes virus (BoHV) in wild ungulates reported from different countries in recent years raises the question of the role of wild animals in the epidemiology of cattle diseases.

Aim of work. To study the prevalence of herpesviruses and pestiviruses in the population of wild artiodactyls of the Moscow region.

Materials and methods. Samples of parenchymal organs and mucosal swabs from 124 wild deer (moose and roe deer) shot during hunting seasons 2019–2022 in Moscow Region were examined by PCR, virological and serological methods for the presence of genetic material and antibodies to bovine infectious rhinotracheitis and viral diarrhea.

Results. BVDV RNA was found in a sample from one moose, BoHV DNA was detected in samples from three roe deer and two moose shot in the Moscow region. Seropositive animals were of different sex and age, the total BoHVs and BVDV seroprevalence rates in wild artiodactyls were 46 and 29%, respectively.

Conclusion. Wild ruminant artiodactyls of the Moscow Region can be a natural reservoir of BoHV-1, and this must be taken into account when planning and organizing measures to control the infectious bovine rhinotracheitis. Cases of BVDV infection in wild artiodactyls are less common, so more research is needed to definitively establish their role in the epidemiology of this disease in cattle.

Introduction. The COVID-19 pandemic combined with seasonal epidemics of respiratory viral diseases requires targeted antiviral prophylaxis with restorative and immunostimulant drugs. The compounds of natural origin are low-toxic, but active against several viruses at the same time. One of the most famous compounds is Inonotus obliquus aqueous extract. The fruit body of basidial fungus I. obliquus is called Chaga mushroom.

The aim of the work ‒ was to study the antiviral activity of I. obliquus aqueous extract against the SARS-CoV-2 virus in vivo.

Materials and methods. Antiviral activity of I. obliquus aqueous extract sample (#20-17) was analyzed against strain of SARS-CoV-2 Omicron ВА.5.2 virus. The experiments were carried out in BALB/c inbred mice. The SARS-CoV-2 viral load was measured using quantitative real-time PCR combined with reverse transcription. The severity of lung tissue damage was assessed by histological methods.

Results. The peak values of the viral load in murine lung tissues were determined 72 hours after intranasal inoculation at dose of 2,85 lg TCID₅₀. The quantitative real-time PCR testing has shown a significant decrease in the viral load compared to the control group by 4,65 lg copies/ml and 5,72 lg copies/ml in the lung tissue and nasal cavity samples, respectively. Histological methods revealed that the decrease in the number and frequency of observed pathomorphological changes in murine lung tissues depended on the introduction of the compound under study.

Conclusion. The results obtained indicate the possibility of using basidial fungus Inonotus obliquus aqueous extract as a preventive agent against circulating variants of SARS-CoV-2 virus.