Voprosy virusologii最新文献

Introduction: 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.

Materials and methods: 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.

Results: 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.

Conclusion: 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.

Introduction: Rotavirus infection is one of the main concerns in infectious pathology in humans, mammals and birds. Newborn piglets or rodents are usually being used as a laboratory model for the evaluation of immunogenicity and efficacy for all types of vaccines against rotavirus A (RVA), and the use of ELISA for the detection of virus-specific antibodies of specific isotype is an essential step of this evaluation.

Objective: Development of indirect solid-phase ELISA with VP2/VP6 rotavirus VLP as an antigen to detect and assess the distribution of RVA-specific IgG, IgM and IgA in the immune response to rotavirus A.

Materials and methods: VP2/VP6 rotavirus VLP production and purification, electron microscopy, PAGE, immunoblotting, ELISA, virus neutralization assay.

Results: The study presents the results of development of a recombinant baculovirus with RVA genes VP2-eGFP/VP6, assessment of its infectious activity and using it for VLP production. The morphology of the VP2/VP6 rotavirus VLPs was assessed, the structural composition was determined, and the high antigenic activity of the VLP was established. VLP-based ELISA assay was developed and here we report results for RVA-specific antibody detection in sera of different animals.

Conclusion: The developed ELISA based on VP2/VP6 rotavirus VLP as a universal antigen makes it possible to detect separately IgG, IgM and IgA antibodies to rotavirus A, outlining its scientific and practical importance for the evaluation of immunogenicity and efficacy of traditional vaccines against rotavirus A and those under development.

Introduction: 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.

Materials and methods: 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.

Results: 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.

Conclusion: 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.

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.

Introduction: Studies aimed at a direct research of human herpes viruses (HHVs) in the tumor material and eye media have not been carried out so far. Research goal to establish the frequency of detection HHVs DNA in the biomaterial of the eye and blood and to assess the specific humoral immunity to the causative agents of herpes virus infections in patients with uveal melanoma.

Materials and methods: 38 patients with the uveal tract tumor were examined for the presence of DNA of HHV types 1 and 2 (HSV-1, 2), Cytomegalovirus (CMV), Varicella Zoster virus (VZV), EpsteinBarr virus (EBV) and herpes viruses 6 and 8 types (HHV-6, HHV-8) in tumor tissue, vitreous body, aqueous humour and blood plasma by real-time polymerase chain reaction; blood serum was studied by enzyme-linked immunosorbent assay (ELISA) for IgG and IgM antibodies to HHVs.

Results: EBV DNA was present in tumor tissue in 20.6% of cases, in vitreous body in 4.2%, in blood plasma in 2.7%, and was not found in aqueous humor. Ig G antibodies to HSV-1, 2 and CMV were detected in 97.3% of cases, VZV 94.6%, HHV-6 32.4%, antibodies to HHV-8 were not detected. 20 patients (55.6%) had reactivation of chronic HSV-1, 2 infection, and 14 (38.9%) patients had reactivation of CMV infection. Markers of chronic EBV infection were found in all patients, its atypical reactivation was observed in 2 cases (5.4%).

Conclusion: Our findings suggest the possible participation of EBV in the oncogenesis of the uveal tract and emphasize the need for further in-depth study of this problem.

Introduction: Insectivores are newly recognized hantaviral reservoir worldwide. Four distinct shrew-borne hantaviruses (family Hantaviridae) have been identified in two regions located in southern and northern part of the Russian Far East, two genetic variants of Seewis virus (SWSV), Lena River virus (LENV), Kenkeme virus (KKMV) and Yakeshi virus (YKSV). Here, we describe geographic distribution of shrew-borne hantaviruses in southern part of the Russian Far East: Jewish Autonomous region, Khabarovsk Krai, Primorsky Krai and Sakhalin region.

Materials and methods: Lung samples from shrews of genus Sorex, captured in the four regions of Far Eastern Russia, were examined for hantavirus RNA using reverse transcription polymerase chain reaction (RT-PCR). Phylogenetic analysis of the partial nucleotide sequences of viral genome was conducted using MEGA X software.

Results: New genetic variant of YKSV was identified in new reservoir host, long-clawed shrew (S. ungiuculatus) from Sakhalin Island. Genetic variant of SWSV, ARTV-Sc, has been found to circulate among S. caecutiens on the seacoast of Khabarovsk and Primorsky Krai. KKMV virus and second genetic variant of SWSV, ARTV-St, were found in S. roboratus and S. tundrensis, respectively from Jewish Autonomous region.

Conclusion: Sorex-borne hantaviruses were found in all studied regions of Far Eastern Russia. Our results demonstrated co-evolution of SWSV, KKMV, and YKSV viruses throughout the geographic distribution of its hosts.

Introduction: The development of drugs against SARS-CoV-2 continues to be crucial for reducing the spread of infection and associated mortality. The aim of the work is to study the neutralization of the SARS-CoV-2 virus with interferon gamma preparations in vitro.

Materials and methods: The activity of recombinant human interferon gamma for intramuscular and subcutaneous administration of 500,000 IU and for intranasal administration of 100,000 IU against the SARS-CoV-2 virus in vitro was studied. The methodological approach of this study is based on the phenomenon of a decrease in the number of plaques formed under the action of a potential antiviral drug.

Results: The antiviral activity of recombinant interferon gamma has been experimentally confirmed, both in preventive and therapeutic application schemes. The smallest number of plaques was observed with the preventive scheme of application of the tested object at concentrations of 1000 and 333 IU/ml. The semi-maximal effective concentration (EC50) with the prophylactic regimen was 24 IU/ml.

Discussion: The preventive scheme of application of the tested object turned out to be more effective than therapeutic one, which is probably explained by the launch of the expression of various interferon-stimulated genes that affect to a greater extent the steps of virus entry into the cell and its reproduction.

Conclusion: Further study of the effect of drugs based on recombinant interferon gamma on the reproduction of the SARS-CoV-2 virus for clinical use for prevention and treatment is highly relevant.

Introduction: On the territory of Russia four species of lyssaviruses (genus Lyssavirus) were identified, three of them caused human deaths.

The aim of work: to characterize fatal cases in humans after contacts with bats in the Far East in 20182021 and to perform typing of isolated pathogens.

Materials and methods: Lyssavirus infection was confirmed in samples of sectional material from people who died in the Amur Region in 2019, in the Primorsky Krai in 2019 and 2021. Diagnostics was performed by fluorescent antibody test (FAT) and RT-PCR using diagnostic kits of domestic production. Viruses were isolated in a bioassay. The nucleoprotein sequences were analyzed after 1st passage. The analysis of phylogenetic relationships and the construction of a dendrogram were performed using the MEGA7 software.

Results: The viruses that caused the fatal cases in humans in the Amur Region and Primorsky Krai share more than 90% identity to Lyssavirus irkut detected in Russia and China. Together they form a separate monophyletic cluster with 100% bootstrap support.

Conclusion: On the territory of Russia, monitoring of bat populations for infection with lyssaviruses is relevant. The material of people who died from encephalomyelitis of unknown etiology within 1015 days from the onset of the disease must be examined for lyssavirus infection. It is necessary to develop PCR assays that employ genus-specific primers. The use of molecular biological methods is promising for improving the diagnosis of rabies and epidemiological surveillance, as well as increasing the efficiency of the system of biological safety of the population of the Russian Federation.