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The transmission of pathogens from animals to humans is the cause of the appearance of the majority of newly emerging diseases. The purpose of this review is to assess the danger of zoonotic pathogens of dangerous and especially dangerous viral infectious diseases as potential agents of pandemics. Materials and methods. The paper presents an analysis of data published in domestic and English-language scientific publications, as well as posted on the Internet. The research method is analytical. The discussion of the results. At least 70 % of all emerging diseases have a zoonotic reservoir. The exponential growth of human activity in previously undeveloped territories determines the increasing influence of zoonotic pathogens. The infection of people with zoonotic pathogens occurs in direct and indirect contact with infected animals and surfaces contaminated with their secretions, transmissible transmission through arthropod bites, food transport through the consumption of contaminated food and drinking water. Two different transmission models have been established among zoonoses from wild animals to man. One of these models assumes, that human infection is a random event with a low probability, in the future, the pathogen is transmitted from person to person. In the second model, direct or vector-mediated pathogen transfer from animal to human is a link in the natural cycle of the pathogen. The risk of transmission of the virus from the zoonotic reservoir to humans is the highest in animal species adapted to human habitats. Conclusions. The highest level of danger as a source of zoonotic diseases represent primates, ungulates, carnivores and especially bats, which are natural reservoirs for a number of dangerous and especially dangerous viral diseases. Representatives of families Poxviridae, Ortomyxoviridae and Coronaviridae have already been caused pandemics, which caused enormous damage to all spheres of human activity. These pathogens can be considered as the most likely agents of future pandemics.

The analysis of existing information about invasion of COVID-19 in Russia shows that that one of leading reason of existing of new rises of covid-19 morbidity is distribution of new genovariants of SARS-CoV-2 virus. The omicron genovariant of SARS-CoV-2 virus was a dominant agent of fifth and subsequent rises of COVID-19 morbidity in Russia. The aim of this work – the estimation of sublines of omicron genovariant of SARS-CoV-2 virus as potential dominant agents of new rises of COVID-19 morbidity in Russia. The source base of the study. Data published in Russian and English-language scientific publications available via the Internet (RSCI, PubMed, Google Scholar). The research method is analytical. Results. The basic properties of omicron genovariant of SARS-CoV-2 virus, epidemical characteristics of the rises of COVID-19 morbidity in Russia, caused by new sublines of omicron variant, estimation ofsublines of omicron genovariant as potential dominant agent of new rises of COVID-19 morbidity in Russia are viewed. It is shown that basic direction of SARS-CoV-2 virus evolution is existing of sublines of omicron genovariant, which are characterized by increased transmissivity but with less severity of the disease caused compared to previously circulated variants of COVID-19agent. The main distinguishing feature of the new subvariants («Kraken», «Czerber», «Centaur», «Arktur», «Pirola») are multiple amino acid exchanges in structural glycoprotein S. The maximum level of variability of this structural protein compared to the original variant of SARS-CoV-2 virus is marked for Pirola subvariant. Onle Kraken subvariant was dominant agent of rise of COVID-19 morbidity in Russia. Conclusion. New rises of COVID-19 morbidity in Russia will not be connected with existing of new subvariants of omicron genovariant, but only with season factor.

After the abolition of the mandatory smallpox vaccination, the humanity lost the immunity not only to smallpox, but also to infections caused by pathogens of this family (Orthopoxvirus): monkeypox, cowpox, buffalo pox, camelpox. Since the camelpox and African gerbil viruses are the closest to the variola virus (genomic homology is 97%) in phylogenetic and genetic terms, it cannot be ruled out that a mutation in a small fragment of the genome of one of these viruses will lead to the replacement of a relatively safe virus with an epidemically dangerous pathogen. The purpose of is article is to summarize materials on the study of camelpox virus. The sources for this research is scientific articles and other English-language literature available via the Internet. The research method is an analysis of scientific sources on camelpox from the general to the specific. The authors considered the epizootic danger of the virus, its virulence for humans, phylogenetic relationship with other orthopoxviruses, means of specific prevention and treatment of camel pox in camels. The discussion and the results. The causative agent of camelpox causes a nodular-pastular rash on the skin and mucous membranes in Camelus dromedaries and Camelus bactrianus. The disease is contagious, and its epizootics lead to significant economic damage. From December 2008 to May 2009, several laboratory-confirmed cases of camelpox in humans were reported in India, Somalia and eastern Sudan. Nowadays for the identification of the camelpox virus, a RT-PCR test system with primers for the C18L gene is usually offered, which detects only this virus. The established host range of the virus is limited to one animal - the camel. To treat sick camels, chemotherapy drugs are used: cidofovir and tocoverimate (ST-246). For immunoprophylaxis, live and inactivated vaccines are used. The conclusion. Camelpox virus poses a risk to humans in regions where people raise camels and are in close contact with them. The immunodeficient populations of people may serve as an additional «window» for the penetration of this virus into human society. The genetic variability of the virus and the plasticity of its genome make it possible to obtain virus strains with altered properties. Synthetic biology methods create a risk, through small substitutions in the genome of the virus, of turning it into an epidemic danger for humans. Constant monitoring of this disease is necessary, since there is a danger of the transmission of camelpox from Kazakhstan to areas bordering the Russian Federation.

The article presents an analysis of studies assessing the effectiveness of new nonspecific medications against hemorrhagic fevers caused by arenaviruses. The possible targets for nonspecific medications, classes of researched antiviral preparations, methods of preclinical investigation of antiviral preparations in vitro and on laboratory animals, as well as prospects for their use in healthcare at present are considered. It has been shown that the level of development of nonspecific medications against hemorrhagic fevers caused by arenaviruses is significantly inferior to those against filovirus infections. Favipiravir should currently be considered as the most effective nonspecific medication against hemorrhagic fevers caused by arenaviruses.

At the beginning of 2020, humanity faced the pandemic of a novel coronavirus infection – COVID-19. The disease has become one of the most contagious for the entire history of mankind. Among medical means of protection, which can be used for prophylactics and treatment of COVID-19, non-specific medical medical protection means play an important role. The aim of this work is to analyze and evaluate the effectiveness of non-specific medical protection means against COVID-19. These medications are divided in two groups in accordance with the targets of their actions. The medications of the first group either block the virus from entering the cell, or inhibit the enzymes involved in viral RNA replication. The other group of medications affects the immune system of a macroorganism, which plays a crucial role in infection resistance, or blocks inflammatory processes in the lungs. Favipiravir is an example of a broad-spectrum antiviral drug with an established activity against SARS-CoV-2 in particular. During the development of new non-specific medical protection means against COVID-19, a comprehensive validation in representative randomized clinical trials is an important condition for their implementation in medical practice.

This review is dedicated to the peculiarities of pathogenesis of the experimental Bolivian hemorrhagic fever (BHF) - the disease, caused by Machupo virus (Arenaviridae family). The authors come to the conclusion that for carrying out preclinical researches of the medical means of protection (MMP) in vivo on small laboratory animals it is expedient to use guinea pigs, infected with a strain of Chicava or with a variant of Carvallo strain, adapted for these animals. The use of guinea pigs as small laboratory animals when studying pathogenesis of the disease caused by Machupo virus allows to carry out statistically reliable definition of quantitative indices of an experimental infection and to select medicines for the final stage of preclinical assessment. As arenaviruses block the process of formation of interferon (IFN) in the infected organism, mice, defective by IFN formation, are the perspective animal models for the study of BHF pathogenesis and may be used for the study of attenuated variants of Machupo virus. The Javanese macaques (Macaca fascicularis) are the laboratory animals, modeling the pathogenetic manifestations of BHF in humans. They can be used when carrying out the final stages of preclinical assessment of means of medical protection.

The article is dedicated to the review of some hazardous and extremely hazardous emergent viral infections of the beginning of the XXI century – severe acute respiratory syndrome (SARS), Middle­East respiratory syndrome (MERS), Lujo hemorrhagic fever (LHF) and severe fever with thrombocytopenia syndrome (SFTS). Special attention is paid to the time of reveal and identification of infectious agents, their taxonomic belonging, genome organization, possible ways of the appearance of strains, virulent for human beings, to endemic regions, probable ways of infection, reservoirs and transmitters of infection, morbidity and mortality. These infections should be of particular concern because of the severity of illnesses, caused by the above mentioned viruses, the absence of characteristic clinical signs that makes diagnostics more difficult, especially in non­endemic areas, the absence of means of specific prophylaxis and treatment and the difficulties in their identification. The analyze of this emergent viral infections reveals their potential threat for the Armed Forces and population of the Russian Federation in case of accidental or intentional delivery of causative agents of these diseases to the Russian territory.

The purpose of the work is to analyze the distribution, natural reservoirs and potential epidemic hazard of new members of the Filoviridae family – Bombali viruses (genus Ebolavirus), Lloviu (genus Cuevavirus), Mengla (genus Dianlovirus), Xylang (genus Striavirus), and Hungjiao (genus Thamnovirus). New filoviruses were detected in Africa (Bombali virus), Europe (Llovi virus) and in Southeast Asia (Mengla, Xylang and Hungjiao viruses). Bats are a natural reservoir for all known filoviruses. This fact is confirmed by the information about the detection of genomic RNA and virus-specific antibodies in them. The isolation of the genomic RNA of filoviruses from bats with the subsequent sequencing and phylogenetic analysis made it possible to identify the Bombali, Lloviu, Mengla, Xylang and Hungjiao viruses as new representatives of the Filoviridae family and to establish their position on the phylogenetic tree of the Filoviridae family. Despite the current lack of information about the isolation of biologically active virus from bats, as well as in spite of lack of established connection between new filoviruses and human diseases, the information that newly identified filoviruses use the same receptors (Neumann-Peak protein) to enter sensitive cells, as the Ebola and Marburg viruses, that are pathogenic for humans, the possible pathogenetic potential of new filoviruses poses a great threat to people living in the territories, inhabited by bats. The possibility of the emergence of new emergent filovirus infections on the territory of Russia necessitates an in-depth study of bats as a natural reservoir of filoviruses in nature.

Reverse transcription-real-time polymerase chain reaction (RT-PCR) is currently the leading laboratory diagnostic tool for COVID-19. With the help of RT-PCR-RT, diagnostics is carried out at the early stages of the development of the disease. The studied clinical samples, as a rule, are swabs from the pharynx and nasopharynx. The aim of the work is to identify and analyze the factors that contribute to false negative results when diagnosing COVID-19 by RT-PCR-RT. It is shown in the article, that the analytical sensitivity of the real-time RT-PCR method is not the main factor in assessing the possibility of obtaining false negative results. The paper considers the effect of drinking hot drinks (tea, coffee), alcohol and smoking (immediately before sampling) on the results of the analysis of swabs from the pharynx and nasopharynx by RT-PCR RT. It was found that the intake of hot drinks before sampling (the probability of obtaining a false negative result is at least 80%) influences most of all on the possibility of obtaining a false negative result in RT-PCR-RT in swabs from the pharynx. The use of small doses of alcohol (0.25–0.33 g of ethanol per 1 kg of body weight) has a lesser effect. Smoking immediately prior to sample collection does not lead to a false negative result in real-time RT-PCR. None of the considered influences affects the possibility of obtaining false negative results in the analysis of swabs from the nasopharynx. Recommendations were made on the need for simultaneous examination of both throat swabs and nasopharyngeal swabs in the ongoing diagnosis of COVID-19.

During the COVID-19 pandemic the experts noted the emergence and periodic change of the dominant variants of the coronavirus (SARS-CoV-2) that caused the disease. The line B.1.1529, the omicron variant according to the WHO classification, became dominant in the fifth wave of the COVID-19 pandemic. The aim of the work is to analyze the properties of B.1.1529 (omicron) viruses that ensure its ability to cause disease in vaccinated or previously recovered from COVID-19. The fifth wave is characterized by the parallel distribution of the delta and omicron variants, with the domination of the latter. The omicron variant arose as a result of multiple passages of SARS-CoV-2 through the organisms of immunocompromised patients. If the delta variant is the most virulent for humans, the omicron variant is certainly the most infectious - the value of the basic reproductive number (R0) for it is ≈ 10.0, for the delta variant ≈ 6, 0. A person infected with the omicron variant is capable of transmitting the SARS-CoV-2 virus within a day. This is caused by a combination of N501Y and Q498R mutations in the omicron variant, which increase the affinity of the receptor-binding domain of the S1 subunit of the viral S protein for the ACE-2 receptor in the human lung. Mutations H655Y and N679K are located near the furin cleavage site, which in turn promotes accelerated cleavage of the S-protein and increases the level of infectiousness of the pathogen. The omicron variant is significantly superior to the delta variant in terms of ability to overcome the immunity caused by vaccination. The spread of the disease was not stopped by the fact that the number of people who completed the full course of vaccination at the beginning of the fifth wave in Russia reached 64%.Therefore, the achieved level of vaccination cannot be considered sufficient to stop the spread of this variant of the virus. It is shown in the article, that this indicator should be at least 80% to prevent the spread of the disease, and only if vaccination is carried out in a short time. However, it is possible that the mutational potential of the SARS-CoV-2 virus has not yet been exhausted, and the pandemic on the omicron variant will not end.

Among the epidemic variants of the SARS-CoV-2 virus the main attention is currently attracted by the delta variant (B.1.617), first identified in India in the end of 2020. Since the appearance of the delta variant, the morbidity rate of COVID-19 in India has increased 20-fold. The overflow of the delta variant of the SARS-CoV-2 virus outside of India is one of the factors in the emergence of the third wave of the COVID-19 pandemic. As of August 24, 2021 the delta variant of SARS-CoV-2 virus has been identified in 193 countries. The purpose of this work is to analyze the delta variant of SARSCoV-2 virus and the features of the disease caused by it. The main features of the delta variant are: a set of mutations affecting a significant functional area of S-protein; a transfer rate from person to person; a reduced incubation period of caused disease. In Russia, the delta variant of SARS-CoV-2 virus appears no earlier than the end of April – beginning of May, 2021. The spread of the delta variant as the dominant one is associated with the emergence in early June 2021 of the third, and in mid-September – the fourth wave of the COVID-19 epidemic in Russia. The epidemiological data for Russia show a sharp increase in the number of new cases of the disease, with a simultaneous increase in the number of hospitalizations and deaths of the disease. The necessary measures to combat the epidemic are: first of all, accelerating the pace of vaccination, as well as the set of administrative measures, including limiting mass events, strict observance of the mask regime and social distance in public places.

Morbidity surveys in certain regions during the COVID-19 pandemic have established that the infection spreads in a wave-like manner characterised with peaks and troughs in incidence. According to the analysis of COVID-19 epidemic development in Russia, surges in COVID-19 infections are mainly driven by seasonal factors, insufficient herd immunity, and emerging SARS-CoV-2 variants with increased transmissibility. The aim of the study was to analyse environmental, biological and social factors contributing to new rises in COVID-19 cases in Russia. The study covers the global epidemiological situation as of mid-2022 and the role of environmental, biological, and social factors in the spread of COVID-19 in the Russian Federation. The results suggest that new highly contagious SARS-CoV-2 variants and seasonality are the principal factors driving new rises in morbidity. The authors assume that the sixth and the seventh COVID-19 waves in Russia will be in line with the best case scenario, which predicts the spread of a SARS-CoV-2 variant with increased transmissibility and reduced virulence.

Cellular immunity plays an important role in the pathogenesis and formation of protective immune defense against the SARS‑CoV‑2 virus.The aim of the work was to study the cellular immunity of rhesus monkeys applying flow cytometry after experimental infection with the SARS‑CoV‑2 virus.Materials and methods. Male rhesus monkeys were intranasally inoculated with the SARS‑CoV‑2 virus, Isolate B strain and hCoV-19/Russia/SP48-1226/2020 strain (abbreviated name U-2), at a dose of 5.0 lg PFU. Using flow cytometry, the levels of 21 populations/subpopulations of mononuclear cells in the peripheral blood of animals were determined before experimental infection with the pathogen and on day 14 after infection. SARS‑CoV‑2 coronavirus RNA was assessed using real-time polymerase chain reaction. Determination of the titer of virus-neutralizing antibodies to the SARS‑CoV‑2 virus in the blood sera of animals was conducted through neutralization test evaluating the ability to suppress negative colonies.Results and discussion. Infection with Isolate B strain culture has led to an increase in the relative content of total T-lymphocytes (p˂0.2), cytotoxic T-lymphocytes (p˂0.1), as well as monocytes expressing the early activation marker CD25 (p˂0.2). The decrease in levels has been observed for total B-lymphocytes (p˂0.2) and T-helper cells (p˂0.1). Infection with the U-2 strain culture revealed an increase in the relative content of monocytes expressing the early activation marker CD25 (p˂0.2). Thus, for the first time in the Russian Federation, flow cytometry was used to study the cellular immunity of rhesus monkeys before and after experimental infection with the SARS‑CoV‑2 virus. The obtained information can be used for studying the pathogenesis of SARS‑CoV‑2 infection, course, and outcome of the disease, and developing strategies for vaccination and treatment.

Since the Dabie bandavirus (DBV; former SFTS virus, SFTSV) was identified, the epidemics of severe fever with thrombocytopenic syndrome (SFTS) caused by this virus have occurred in several countries in East Asia. The rapid increase in incidence indicates that this infectious agent has a pandemic potential and poses an imminent global public health threat. The analysis of molecular evolution of SFTS agent that includes its variants isolated in China, Japan and South Korea was performed in this review. The evolution rate of DBV and the estimated dates of existence of the common ancestor were ascertained, and the possibility of reassortation was demonstrated. The evolutionary rates of DBV genome segments were estimated to be 2.28 × 10-4 nucleotides/site/year for S-segment, 2.42 × 10-4 for M-segment, and 1.19 × 10-4 for L-segment. The positions of positive selection were detected in the viral genome. Phylogenetic analyses showed that virus may be divided into two clades, containing six different genotypes. The structures of phylogenetic trees for S-, M- and L-segments showed that all genotypes originate from the common ancestor. Data of sequence analysis suggest that DBV use several mechanisms to maintain the high level of its genetic diversity. Understanding the phylogenetic factors that determine the virus transmission is important for assessing the epidemiological characteristics of the disease and predicting its possible outbreaks.

The main triggers of new infectious diseases, including those with pandemic potential, are: spontaneous emergence of infectious strains which are more virulent for humans and contribute to transmission of pathogenic microorganisms, environmental changes, social and economic factors, increased contact rates between different regions. A successful pandemic response requires mass immunisation against a specific disease, aimed at the development of herd immunity which is based on the concept of indirect protection of the whole of the population by immunising a part of it. A well-grounded choice of the vaccine platform is central to dealing with this problem. The aim of the study was to compare characteristics of vaccine platforms (attenuated, inactivated, subunit, recombinant vector, DNA, and RNA vaccines) intended for mass immunisation against dangerous and extremely dangerous viral infections with pandemic potential. The study focused on the members of Poxviridae, Orthomyxoviridae and Coronaviridae families as potential pathogens. The vaccine platforms were compared in terms of the following parameters: capability of producing a robust immune response; protective efficacy; time required for vaccine development and testing; ability to produce vaccine in volumes required for mass immunisation; potential obstacles associated with the intended use of the vaccine. It is expected that in the next few decades DNA and RNA vaccine platforms will be most widely used for development of products against dangerous and extremely dangerous viral infections with pandemic potential, regardless of taxonomic groups of pathogens.

The pandemic of the new coronavirus (COVID-19) disease that began in December 2019 in China is still having a huge impact on all spheres of human life. The herd immunity, which is the most effective tool for preventing the spread of the disease, is formed in two ways: the passive way (i.e., the formation of a population not susceptible to re-infection due to the natural spread of the disease) and the active way (mass immunisation). High rates of COVID-19 vaccination were achieved thanks to the development and mass production of new vaccines. The selection of the most promising vaccine platforms is one of the key aspects of successful mass immunisation. The aim of the study was to compare the characteristics of COVID-19 vaccines used for mass immunisation. The paper analyses the vaccine technology platforms, efficacy of different types of vaccines based on clinical trial results, safety of vaccines for different population groups, and potential for scaling up vaccine production in order to ensure the necessary vaccination coverage. The vaccines currently used for mass immunisation are: BNT162b2 (Pfizer/BioNTech), mRNA1273 (Moderna), Gam-COVID-Vac (N.F. Gamaleya National Research Center for Epidemiology and Microbiology), Ad26.COV2.S (Johnson & Johnson), ChAdOx1-S (AZD1222) (AstraZeneca), BBIBP-CorV (Sinopharm), CoronaVac (Sinovac Biotech), and NVX-CoV2373 (Novavax). The comparison of the main characteristics of the vaccines demonstrated that the most promising types of vaccines for COVID-19 specific prophylaxis are RNA vaccines and recombinant adenovirus vector-based vaccines.

Although successes in antiretroviral therapy (ART) turned AIDS from lethal illness into sluggishly progressing disease, its prevention and treatment remain one of the most socially significant concerns. The increase in the number of patients infected with human immunodeficiency virus (HIV), especially in the USA, South America and Europe, determines the need in creating a vaccine against this disease. Existing vaccination practice has demonstrated efficiency of priming/boosting scheme for the development of immune responses. As anti-vector immunity of priming vector can constrain the response to boosting immunization with the same vaccine, heterologous priming/boosting vector constructs are used. An ideal AIDS vaccine would prevent virus dissemination and control viral replication, but it also must be safe for HIV-infected contingent. The vaccination of HIV-infected individuals is used for enhancing immune-mediated elimination of persistently HIV-infected CD4+ Т-cells during long-term ART in order to purge the latently infected viral reservoirs. The paper considers the results of clinical trials of DNA-anti-HIV/AIDS vaccines and recombinant MVA strain of vaccinia virus, expressing different combination of HIV genes, which demonstrated the safety and tolerability both, in HIV-infected and non-HIV-infected volunteers. All implemented schedules of vaccination induced cell-mediated and humoral immune responses in all volunteers. And though there are no data on acquiring AIDS by HIV-uninfected volunteers from groups at low risk of HIV-infection, there are no grounds to conclude the sufficiency of induced protection for the prevention of possible HIV infection.

Introduction. The outbreaks of the Zaire ebolavirus (ZE) disease (ZED) that have arisen in the last decade determine the need to study the infection pathogenesis, the formation of specific immunity forming as well as the development of effective preventive and therapeutic means. All stages of fight against the ZED spread require the experimental infection in sensitive laboratory animals, which are rhesus monkeys in case of this disease . The aim of the study is to evaluate the rhesus monkey cellular immunity following the ZE experimental infection by the means of flow cytometry (cytofluorimetry). Material and methods. Male rhesus monkeys were intramuscularly infected by the dose of 15 LD50 (dose of the pathogen that causes 50% mortality of infected animals) of the ZE, the Zaire strain (ZEBOV). Levels of 18 peripheral blood lymphocyte populations of the animals before the ZE experimental infection and at the terminal stage of the disease were assessed using flow cytometry. Results and discussion. The certain changes in the levels of the lymphocyte populations were observed following infection, indicating simultaneous activation and suppression of the immune system during ZED. The increase in content was observed for T-lymphocytes, T-helper and cytotoxic T-lymphocytes expressing the corresponding markers of early activation. The decrease was recorded for T-lymphocytes and double-positive T-lymphocytes expressing corresponding markers of late activation, as well as natural killer cells expressing CD8 (p 0.05). Conclusion. For the first time in the Russian Federation, the rhesus monkey cellular immunity before and after the ZE experimental infection was assessed using flow cytometry.

The introduction of SARS-CoV-2 coronavirus from a natural reservoir into the human population subsequently caused the COVID-19 pandemic, that had a huge impact on all spheres of human activity dramatically increased interest in this group of viruses. Given that such an introduction of the coronavirus was already the third in a row in 21 century (after outbreaks caused by SARS-CoV and MERS-CoV viruses), there are quite good reasons to fear the appearance of new diseases, the etiological agents of which will be representatives of the Coronaviridae family in the future. The purpose of this review is to assess the potential risk of coronaviruses of animals as possible human pathogens. When preparing the review, the following data were used: data published in leading foreign journals as well as in Internet sources that address some aspects of the COVID-19 pandemic. The following main aspects of this problem are considered: a spontaneous formation during the evolution of animal coronaviruses, highly pathogenic to humans; a possibility of transmission of human coronavirus to animals, its genetic interaction with the coronavirus, the owner of which is this animal, the acquisition of viral progeny, a set of new properties and reverse transmission from animal to man a pathogen that may have increased pathogenicity. Animal coronaviruses are considered by belonging to a certain taxonomic group of their natural hosts. The main focus is on bat coronaviruses (as a reservoir of SARS-CoV, MERS-CoV and SARS-CoV-2 viruses), as well as avian coronaviruses, due to the potential ability of these animals to become vectors of spread of new emergent diseases and the coronaviruses of carnivores, due to the established during the COVID-19 pandemic fact of transmission of the SARS-CoV-2 virus from man to mink and from mink to man. Studying the features of molecular evolution it will help you better understand the mechanisms of occurrence and adaptation to humans pathogens of emergent viral diseases.

Objective. Selection of indicators of lymphocyte populations in rhesus macaques determined by flow cytometry to evaluate variations of cellular constituent of their immune status.Materials and methods. Blood of 11 healthy rhesus macaque males, 2,0–2,5 years old, weighing 2,5–3,0 kg, was used. Monkeys were examined simultaneously in each of 7 months of observation (since May till November). Immunophenotyping was conducted by FC500 cytofluorimeter using Affymetrix eBioscience monoclonal antibodies. The following cellular constituent indicators of immune status were differentiated: total T lymphocytes (phenotype CD2+CD20-); total B lymphocytes (phenotype CD2-CD20+); natural killer cells (phenotype CD2+CD56+); T helper cells (phenotype CD2+CD4+); cytotoxic T lymphocytes (phenotype CD2+CD8+); double-positive T lymphocytes (phenotype CD4+CD8+) and T lymphocytes positive by antigens CD2 and CD20 (phenotype CD2+CD20+).Results and discussion. Statistical analysis of the obtained results revealed the absence of the effect of research time factor on the stated indicators. To assess changes in the cellular constituent of immune status of rhesus macaques, it is possible to use indicators that are less variable: total T and B lymphocytes, T helper cells, cytotoxic T lymphocytes and T lymphocytes with phenotype (CD2+CD20+). The use of CD56 as a marker of natural killer cells of rhesus macaques is impractical due to its low expression and a small size of the population bearing this marker. The research results may form the basis of the normative indicators of the subpopulation cell composition of immune system in rhesus macaques, which will allow the study of infected animals when assessing the quality of medical products in relation to dangerous and particularly dangerous infections.

The number of confirmed COVID-19 cases worldwide amounted to 50 million at the beginning of November 2020. This is clearly not enough for the formation of herd immunity, which will prevent repeated outbreaks of the disease. Quarantine measures can only curb the spread of the disease to some extent, therefore specific preventive measures are needed to create collective immunity to COVID-19.The underlying principle of collective immunity is indirect protection of the whole of the population by immunising a certain part of it. Vaccination is the most effective approach to prevention of epidemic outbreaks. The aim of the study was to analyse promising approaches to the development of vaccines against novel coronavirus COVID-19 infection. The paper summarises data on development studies and clinical trials of COVID-19 vaccines conducted in different countries. It analyses the pros and cons of different platforms for vaccine development (attenuated vaccines, inactivated vaccines, subunit vaccines, DNA and RNA vaccines, recombinant vector vaccines). The paper presents a potential design of novel vaccines. It was concluded that COVID-19 vaccines might be developed both for immunising high-risk groups and for mass immunisation. An optimal solution for the second task would be to develop human or monkey adenovirus vector-based vaccines whose mass production has already been unveiled.

The genetic diversity of coronaviruses and their variability are provided by high frequency of recombination of their genomic RNA that assists spontaneous emergence of viruses with new characteristics, which potentially may be agents of novel extremely dangerous and exotic infectious diseases. In December 2019 – January 2020 the novel coronavirus disease, caused by SARS-CoV-2 virus, subsequently named COVID-19 (Corona Virus Disease 2019), was revealed in China. The aim of this work is to analyze the possible mechanism of COVID-19 outbreak and the properties of the possible etiological agent of the disease, SARS-CoV-2 virus. A comparison of zoonotic reservoirs of highly pathogenic human coronaviruses, agents of severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and SARS-CoV-2, as well as the clinical signs of the diseases, caused by them, are presented. The possible mechanism of epidemic outbreaks is considered. The chronology of COVID-19 outbreak (later escalated into a pandemic) from the beginning of December to the end of March, taxonomical and molecular-biological characteristics of ethiological agent of disease, SARS-CoV-2 virus, and its place on phylogenetic tree of coronaviruses are presented. The main directions of the struggle with the spread of the infection are considered.

The COVID-19 pandemic posed many questions to world health. They could be satisfactorily answered only after a thorough study. During the initial period of the COVID-19 pandemic (early January 2020), it was considered a local outbreak of emergent coronavirus infection with an undetermined possibility of person-to-person transmission. However, on March 11, the World Health Organization (WHO) upgraded the status of the COVID-19 outbreak from epidemic to pandemic. The aim of this article was to analyze possible scenarios of the development of COVID-19 epidemics in Russia. COVID-19 infection occurs mainly in the beginning stage of the disease, when patients are not yet diagnosed. This is the fundamental difference between COVID-19 and SARS or MERS, in which patients become contagious after onset of symptoms of the disease. Based on the study of dynamics of changes in certain epidemiological characteristics, the epidemic in Russia was compared in this article with the same epidemics in China, Italy, Germany and the United States. The authors came to the conclusion, that the COVID-19 epidemic in Russia was different from the above mentioned epidemics, because the capital region (Moscow and Moscow region), the largest center of transport communications, became the epicenter of the epidemic in Russia. They considered different variants of epidemic development in Russia, depending on the intensity of ongoing anti-epidemic measures. To describe the spread of the epidemic, the SIR model (Susceptible Infected Recovered) proposed by Scottish epidemiologists W.O. Kermack and A.G. McKendrick was used. Based on the data obtained, it turned out to be possible to tentatively determine the final date of the active phase of the COVID-19 epidemic (after which it is possible to register only a limited number of cases of the disease). This date should come about 6 weeks after the completion of the plateau phase. The beginning of the plateau phase was early May 2020, and the end of the plateau phase should be mid June 2020. The estimated completion date should be August 8–25, 2020. The total number of people with a confirmed diagnosis could be 991–1122 thousand.

The area affected by the disease caused by Madariaga virus has been expanding recently. Given the geographic location of the endemic regions that overlap with tourist destinations, as well as the confirmed possibility of importing the disease, we cannot rule out the risk of appearance of this disease in Russia. The aim of the study was to analyse the properties of Madariaga virus (Alphavirus genus, eastern equine encephalomyelitis virus complex) and some epidemiological and epizootological characteristics of the virus-associated disease which manifests itself in diffuse inflammation of brain and spinal cord. Based on both ecological and molecular genetic characteristics of Madariaga virus, it is classified as an individual virus which is part of the eastern equine encephalomyelitis virus complex. There is evidence that this pathogen can cause epizootic outbreaks in horses, infect other types of mammals (rats, bats), as well as, potentially, birds and reptiles. The reservoir of infection is the short-tailed cane mouse (Zygodontomys brevicauda). Human cases have also been described, and the potential route of infection was identified as transmission via mosquito bites. Vectors of pathogen transmission are mosquitoes of the Culex, Aedes, and Psorophora genera. Serological studies carried out in Panama revealed the presence of antibodies to Madariaga virus in 2–5% of the examined patients, which indicates the existence of asymptomatic infection along with clinically apparent infection. Phylogenetic analysis of strains isolated from infected people showed that the strains belong to lineage III of the eastern equine encephalomyelitis virus subtype common in Central and South America. The paper summarises the results of assessment of potential risk factors of Madariaga virus infection in endemic regions that was performed using the Akaike information criterion. Risk groups in endemic regions are represented by farm workers and fishermen. The results of the studies show that the area affected by the disease is expanding, and the strains that belong to genetic lineage III of the eastern equine encephalomyelitis virus pose the greatest epidemic risk.

The article describes different generations of antisense oligonucleotids (unmodified oligonucleotids, phosphorothioate oligomers, 2’-0-methyl and 2’-0-methoxy-ethyl modification of oligomers, phosphordiamidate morpholine oligomers and small interfering RNAs), the possible mechanism of their action, their use for prevention and treatment of hazardous and extremely hazardous viral infectious diseases. Phosphordiamidate morpholine oligomers and small interfering RNAs are most widely used in the development of emergency prevention and treatment of hazardous and extremely hazardous viral infectious diseases. The authors conclude, that further improvement of medications based on antisense oligonucleotids may be achieved by improving the structure of the latter and carrying out the search for new chemical modifications.

The article presents an analysis of research evaluating the effectiveness of nonspecific means of emergency prevention and treatment of Ebola virus disease. It considers the most significant results of preclinical and clinical trials of nonspecific therapeutics for the causative agent of Ebola hemorrhagic fever, as well as the prospects for their use in healthcare practice at present. It has been established that the general tendency to create nonspecific means of prevention and treatment of Ebola virus disease is not the development of new drugs, but the attempts to detect the antiviral activity of already known drugs that previously had a different purpose. Favipiravir is considered as the most effective nonspecific therapeutic against Ebola virus disease.

Haemorrhagic fever caused by the Ebola virus is a highly hazardous infectious disease with a mortality rate of 50– 90 %. Heterologous immunoglobulins with a high virus-neutralizing titer are an important element of the WHO-endorsed set of measures for emergency prevention and treatment of the disease. Specific activity of these products is largely determined by their fractional composition, and, in particular, by molecular mass distribution (MMD). The size-exclusion-high-performance liquid chromatography (SEC-HPLC) has traditionally been used for determination of the MMD of the target protein in human immunoglobulin-based products. The use of this method for evaluation of molecular parameters of heterologous immunoglobulin requires confirmation of its specificity, accuracy and precision, and establishment of the chromatographic system suitability criteria in the context of a new test object. The aim of the study was to test the applicability of the SEC-HPLC method to the assessment of molecular parameters of anti-Ebola immunoglobulin derived from horse serum. Materials and methods: three batches of purified equine anti-Ebola immunoglobulin were used in the study. Normal equine and human immunoglobulins of the IgG isotype were used as reference standards. The HPLC test procedures described in the European Pharmacopoeia 9.6 and State Pharmacopoeia of the Russian Federation, 14th ed., were used for determination of monomers and other immunoglobulin fractions. An Agilent 1260 Infinity (Agilent, USA) HPLC system with a diode array detector and an Agilent Bio SEC-3 HPLC column were used for quality evaluation of the tested products. Results: the resolution factor between IgG monomer and dimer peaks (1.69 and 2.10), and the chromatographic column efficiency (>2000) make it possible to use the SEC-HPLC system for evaluation of molecular parameters of heterologous immunoglobulin. The study demonstrated reproducibility of the test procedure. Conclusions: the study confirmed the applicability of the SEC-HPLC procedure for evaluation of molecular parameters of anti-Ebola immunoglobulin derived from horse serum. It demonstrated the compliance of the purified immunoglobulin to the national and international quality requirements in terms of «Molecular parameters».

The Ebola virus (member of Ebolavirus genus Filoviridae family) is the etiologic agent of extremely hazard human disease with high mortality rates (up to 90%). The most important components of spectrum of therapeutics for special prophylactic and current of disease, caused by Ebola virus, are prepares, based on virus specific antibodies (convalescent’s plasma, geterologic immunoglobulins, monoclonal antibodies. The use of different class therapeutics, based on virus specific antibodies, the possible improvements of its composition and strategy of its application for special prophylactic and current of disease, caused by Ebola virus, are considered in this review.

Chikungunya virus belongs to Alphavirus genus of the Togaviridae family. It is a member of Semliki Forest virus antigenic complex that includes antigenic related Semliki Forest, Chikungunya, O’ Nyong-nyong, Ross River viruses. Chikungunya virus is the causative agent of acute febrile illness with myalgia and arthralgia in humans. Since its discovery in 1952, Chikungunya virus caused sporadic and infrequent outbreaks. Since 2004, global Chikungunya outbreaks have occurred. Now Chikungunya is viewed as a global public health issue in many countries, where Aedes mosquito vectors are widespread. Currently, four genotypes of Chikungunya virus (West African, South African, Asian and Indian Ocean) are distinguished. Appearance of different genotypes is associated with adaptive mutations in peplomers of E1 and E2 glycoproteins. It is shown, that a single mutation in E1 glycoprotein (alanin for valin substitution in 226 position) leads to increasing virus virulence (50-100 times). This mutation is instrumental for epidemic potential increase. For virus variants with this mutation, secondary substitutions enhancing viral virulence are described too. Аedes aegypti mosquitoes are common vector for all genotypes of Chikungunya virus, Аedes albopictus mosquitoes are vector, mainly, for South African and Asian genotypes. They play the leading role in epidemic potential increase over the last decade. The effectiveness of Chikungunya virus transmission by Аedes аegypti mosquitoes is 83.3 %, by Аedes albopictus mosquitoes - 96.7 %. The Аedes albopictus are more widely disseminated than Аedes аegypti (about 40 percent of all land territory). Demonstrated is the possibility of transcontinental spread of Аedes albopictus mosquitoes by aviation and naval transport. This review highlights the most recent advances in our knowledge of the ecology, epidemiology and molecular biology of Chikungunya virus. These data play an important role in the development of preventive, treatment and vaccination strategies of Chikungunya fever.

The review presents the results of preclinical use of vector vaccines against human immunodeficiency virus (HIV) disease and simian immunodeficiency virus (SIV) disease. Application of antiretroviral therapy exclusively is insufficient for elimination of HIV from patient’s body. This dictates the need for an effective vaccine which will reduce the number of new cases of the disease and reduce the risk of virus transmission. Current practice of medicinal product development showed the effectiveness of heterologous prime-boost regimens for the induction of expressed immune response in laboratory animals. Various vector constructs were used as priming vaccines: DNA vaccines, Bacille Calmette-Guerin vaccine, chimpanzee adenovirus, vesicular stomatitis virus, alphavirus repli-clone. Booster vaccine was represented by recombinant MVA strain. In all vector vaccines, different genes of immunodominant antigens of HIV and SIV agents were inserted. On rhesus macaques, murine, rabbit models, it was demonstrated that deployed vaccination schemes were safe and induced immune response. Because membrane HIV protein is highly variable, strongly glycoziled and subjected to structural changes during receptor binding, it cannot be viewed as a target for induction of virus neutralized antibodies. Therefore, we mainly studied the cell immune response that was presented by poly-functional CD8+ T-cells. However, some recent researches are aimed at such modification of envelope HIV immunogene that would provide for virus neutralizing antibody induction. The study of protective efficiency of the induced immunity in rhesus macaques, immunized with recombinant vectors expressing SIV’ s immunodominant antigens, in case of subsequent inoculation with virulent SIV strain has revealed that all monkeys developed illness. Assuming that the constructions with SIV’ s immunodominant antigens under protective efficiency testing on rhesus macaques imitate AIDS in humans, it seems that vaccines, developed up-to-date, will not be effective for collective immunity formation against AIDS. Therefore, the search for novel combinations of expressed immunodominant antigens for the inclusion into the composition of priming and booster vaccines remains a priority area at present time.

The mosquitoes of Aedes genus are the most important vector such arboviral diseases as dengue, yellow, Chikungunya, West Nile and Zika fevers. Work is currently in progress to control the transmission of agents of these diseases by forming of transgenic mosquitoes in order to altering the capacity of wild mosquitoes to support of virus replication. There are two main strategies of genetic control of mosquitoes population. Sterile Insect Technique (SIT), that mainly uses population suppression methods for making self-sustaining genetic systems and Release of insects carrying of a Dominant Lethal (RIDL) that uses mainly gene transfer methods for making of self-limiting genetic systems. The RIDL is more expensive, but it has some significant preferences, according compares with SIT. The field trials of genetic control methods are conducted in several countries from 2009 to present time. Genetic control, transgenic technologies to induce sterility, genetic elimination and stable transformation of Aedes mosquitoes are viewed in this review.

Some drugs candidates for treatment of Ebola virus disease (EVD), have been studied, monoclonal antibody (mAb) cocktails have shown great potential as EVD therapeutics. The advantages of mAb therapy include low toxicity, high specificity and versatility, with the range of biological effects being dependent upon the Fc region. Functions of mAbs include pathogen opsonisation, complement activation, antibody-dependent cell cytotoxicity and virus neutralization characteristics. The most known mAb cocktail, used as therapeutic, is ZMapр, manufactured by Leaf Biopharmaceutical from 2004. The elaborated mAb cocktails, structures and properties s of mAbs, the protective characteristics of mAbs and development of new pan-ebolavirus mAbs are reviewed in this article.

Тhе kingdom Archaea, as well as Bacteria, belongs to the overkingdom Prokaryota. Halophilic archaea (Halorubrum lacusprofundi) isolated from Antarctic saline lakes contain plasmids (pR1SE) that code proteins taking part in the formation of membranes of archaea vesicles. The molecular and biological properties of pR1SE and the peculiarity of its interaction with sensitive cells are considered in this article. The role of structural proteins coded by pR1S in the process of formation of vesicle membrane complex is paid special attention. Plasmid-containing archaea vesicles model some properties of viruses. Archaea plasmids can be viewed as possible ancestors of DNA-containing viruses.

Presently, the Arenavirus genus (Arenaviridae family) includes 26 individual species of viruses. It is divided into two main groups – Old World arenaviruses and New World arenaviruses. The New World arenaviruses comprise four clades: А, B, C, D; pathogenic for humans New World arenaviruses are attributed to clade B. Lassa, Lujo, Machupo, Junin, Guanarito and Sabia viruses are the agents of extremely hazardous hemorrhagic fevers (Lassa hemorrhagic fever, Lujo hemorrhagic fever, Bolivian hemorrhagic fever, Argentinean hemorrhagic fever, Venezuelan hemorrhagic fever, Brazilian hemorrhagic fever, accordingly). These arenaviruses pose a potential threat to national public health due to the possibility of their accidental importation into the territory of the Russian Federation. The vaccination of risk group is the most effective and money-saving means of protection against epidemic spread. Objective of this review is to analyze the specific preparations for arenaviral hemorrhagic fever prevention that are currently under development. Production of live vaccines based on attenuated strains of the agents, the DNA vaccines, vector recombinant vaccines and vaccines on the basis of RNA-replicons is viewed as the main trends in the area. Тhe most important results in the development of effective prophylactic means against arenaviral hemorrhagic fevers are discussed in this paper.

The data on a recently revealed novel filovirus (Lloviu virus, family Filoviridae, genera Cuevavirus) in Europe are viewed in this issue. The molecular-biological properties of genome fragments of Lloviu virus were isolated from perished bats (Miniopterus sсhreibersii). Because infectious Lloviu virus has not been isolated yet, the capacity of virus to infect cells of different species and its potential to cause disease in humans is unclear. The recombinant vectors (vesicular stomatitis virus and plasmids) expressing structural proteins of Lloviu virus were used to study different elements of the virus. The question of interaction of structural proteins of Lloviu virus expressed by recombinant vectors with receptors of bat and human cells is considered. The possibility of pathogenicity of the novel agent for humans is considered. The conclusion is made about the necessity of continuous epidemical and epizootical monitoring of the new filovirus infection.

Ebola virus that composed Ebolavirus genus of Filoviridae Family causes severe hemorrhagic fever in humans with high case-fatality rates (up to 90%). The Ebolavirus genus includes Ebola-Zaire, Ebola-Sudan, Ebola-Reston, Ebola-Tai Forest and Ebola-Bundibugyo viruses. The date about epidemic outbreaks of disease, reservoirs of infection, accidental hosts of Ebola virus are presented in this review. The date about natural reservoirs of infection are accessed only for Ebola-Zaire and Ebola-Reston viruses. For Ebola-Sudan, Ebola-Tai Forest and Ebola-Bundibugyo viruses such information is absence. The bats are natural reservoirs for Ebola-Zaire and Ebola-Reston viruses. The formation of natural reservoirs of filoviruses assumes possibilities of existence of several hosts. The interrelation of Ebola virus and their hosts, dynamics of infection are the classical «susceptible-infected-immune» (recovered) cycle. The likely schemes of rises of epidemic outbreaks, caused by Ebola-Zaire virus are suggested.

Nodular dermatitis, (dermatitis nodularis), is an exotic for the Russian Federation poxviral disease. Some epizootical characteristics of it, problems of laboratory diagnostics, and possible reasons of extension of agent spread areal are discussed in this review. Phylogenetic analysis of P32 gene nucleotide sequences of dermatitis nodularis virus has also been conducted. It is noted that taking into account the economic loss caused by the disease and possibility of its import into non-enzootic regions, it is necessary to use existing effective means of specific prophylacsis extensively. The swift outspread of the disease in the Russian Federation should be considered as the risk factor for biological safety of our country.

The brief review is devoted to description of the discovery of giant viruses belonging to the families of Mimiviridae and Marseilleviridae, as well as unassigned genera Pithoviruses, Pandoravirus, and Molliviruses. The review presents issues of their origin, evolution, and molecular-biological characteristics.

Lujo hemorrhagic fever (LHF) is a viral disease accompanied with fever, headache, vomiting, diarrhea, arthralgia, myalgia and numerous signs of hemorrhagic syndrome. LHF causes a clinical syndrome remarkably similar to Lassa hemorrhagic fever. The first case of LHF occurred in Johannesburg, South Africa, in 2008. There was a secondary transmission from the index patient to four healthcare workers. Four of the five patients died. The etiologic agent of LHF is Lujo virus (LUJV) belonging to Arenavirus genus of the Arenaviridae Family. Virus Lujo is the second pathogenic arenavirus, after Lassa virus, to be recognized in Africa during the last 40 years. Data about epidemiology, clinical characteristics and diagnostics of LHF, properties of Lujo virus (according to phylogenetic analysis), and recommended precautions for preventing secondary transmission are considered in this paper.

The Arenaviridae family consists of a large group of single strand ambisense RNA viruses that are separated phylogenetically, serologically and geographically into Old World and New World viruses. Recent studies indicate that cellular entry of arenaviruses requires a series of cellular protein interaction and molecular mechanisms. The arenaviruses entry into cells is initiated by the interaction of viral glycoprotein with one or more receptors on the surface of host cells. The main host cell factors that are involved in filovirus entry are attachment factors (α-dystroglycan for Old World and human transferrin receptor 1 for New World viruses), endolisosomal host cell factors (cathepsins B and L and Niemann-Pick C1 protein). The review presents the modern knowledge about the role of structural proteins of arenaviruses and some cell factors in pathogenesis of the diseases, caused by arenaviruses.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by a new virus (SFTS virus) reported to be endemic to central and northeastern parts of China. SFTS virus, which is classified into the genus Phlebovirus (the Bunyaviridae family), is suspected to be a tick-borne virus owing to evidence in two species of ticks: Haemaphysalis longicornis and Rhipicephalus microplus. SFTS virus is detected among many species of domestic animals in China. The clinical symptoms of SFTS include fever, thrombocytopenia, leucocytopenia, gastrointestinal symptoms, neural symptoms, bleeding tendency. The fatality rate of SFTS is 6-30%. Person-to-person transmission of SFTS virus is possible through blood contact. Clinical and epidemiological studies of SFTS, the cases of SFTS outside China, person-to-person transmission of SFTS virus, evolutionary and molecular analysis of the emergent SFTS virus, and risk assessment of human infection with a novel phlebovirus are considered in this review.

In 2009, a novel virus, named severe fever with thrombocytopenia syndrome (SFTS) virus, was isolated from a patient in China. The illness caused by this novel virus is characterized by a sudden onset of fever and respiratory or gastrointestinal disorders, followed by progressive thrombocytopenia and leucocytopenia, the case-fatality rate amounting to 6–30 %. Genomic sequencing of the isolated agent indicated that the SFTS virus constituted a new (third) group of Phlebovirus genus, Bunyaviridae family. Presently, different means for specific diagnostics of SFTS (real-time reverse transcription polymerase chain reaction, indirect fluorescent antibodies method, enzyme-linked immune-sorbent assay) are developed. Constructing of diagnostic kits, basic characteristics of methods for determination of causative agent of infection or specific antibodies against it are considered in this review.

Aim. Detection and identification of Venezuelan equine encephalomyelitis (VEE) virus RNA in biological samples by reverse-transcription polymerase chain reaction (RT-PCR) and RT-PCR in real time (rRT-PCR). Materials and methods. VEE, Sindbis, West Nile, Japanese and tick-borne encephalitis viruses were studied. Cell culture of chicken fibroblasts, outbred mice and rats, Javanese macaques were used in the experiments. Biological activity determination of the running culture of causative agents used in the experiments was carried out by negative colony method in monolayer cell culture under agar coating and using intra-cerebral infection of mice. Reagent kits developed in the 48th Central Research Institute and Institute of Analytical Instrument Engineering were used during execution of experiments of VEE virus RNA detection by RT-PCR and rRT-PCR. Results. VEE virus was detected in biological samples by various methods. Data from RT-PCR and rRT-PCR are in accordance with the results of virus detection in samples using sensitive animals. Conclusion. Use of molecular-diagnostics methods for detection in biological samples of a causative agent of a dangerous infectious disease is important for procuring biological safety of Russian Federation.

Aim. Experience of study and possible ways of elimination of false positive and false negative results during execution of polymerase chain reaction on an example of Junin virus RNA detection. Materials and methods. Junin virus - causative agent ofArgentine hemorrhagic fever (AHF) strain XJpR37/5787 was obtained from the State collection of pathogenicity group I causative agents of the 48th Central Research Institute. Reagent kit for detection of Junin virus RNA by RT-PCR was developed in the Institute and consists of 4 sets: for isolation of RNA, execution of reverse-transcription reaction, execution of PCR and electrophoretic detection of PCR products. RT-PCR was carried out by a standard technique. Continuous cell cultures of African green monkey Yhro B, GMK-AH-1(D) were obtained from the museum of cell culture department of the Centre. Results. An experimental study of the effect of various factors of impact on the sample under investigation («thawing-freezing», presence of formaldehyde, heparin) on the obtaining of false negative results during Junin virus RNA detection by using RT-PCR was studied. Addition of 0.01% heparin to the samples was shown to completely inhibit PCR. Addition of 0.05% formaldehyde significantly reduces sensitivity of the method. A possibility of reduction of analysis timeframe from 15 to 5 days was shown during detection of the causative agent in samples with low concentration of the latter by growing the samples and subsequent analysis of the material obtained by using RT-PCR. Conclusion. During detection of causative agent by using RT-PCR false negative results could appear in the presence of formaldehyde and heparin in the sample. A possibility of elimination of false negative PCR results due to concentration of the causative agent in the sample under investigation at a level below sensitivity threshold was shown on the example of Junin virus RNA detection by using growing of the pathogen in appropriate accumulation system with subsequent analysis of the material obtained using PCR.

Epidemiologic analysis of epidemic outbreaks caused by American equine encephalitis causative agents is carried out in the review. Eastern equine encephalomyelitis (EEE), Western equine encephalomyelitis (WEE) and Venezuela equine encephalomyelitis (VEE) viruses are etiologic agents of dangerous transmissive diseases that are usually accompanied by fever and neurologic symptoms. Among the New World alphaviruses, VEE virus has the most potential danger for humans and domestic animals. Currently, enzootic strains of VEE play an increasing role as etiologic agents of human diseases. Most of the VEE cases in humans in endemic regions during inter-epidemic period are caused by infection with VEE subtype ID virus. A possibility of emergence of novel epidemic outbreaks of VEE is determined by mutations of ID subtype strains into IC subtype, and those currently pose a potential threat as an etiologic agent of the disease. Despite low morbidity, EEE and WEE are a problem for healthcare due to a relatively high frequency of lethal outcomes of the disease.

Nowadays vaccination of the population living in the endemic regions and widespread implementation of the potent therapies for the emergency prophylaxis and treatment into the clinical practice are regarded as the basic efficient and cost-effective measures for Ebola epidemic spread control. Objective of the review is to analyze current state of the development of aids for the immediate prophylaxis and treatment of Ebola fever. Focus area of the activities is the construction of drugs on the basis of virus-specific anti-bodies (including monoclonal), small interfering RNA, and anti-sense phosphordiamidate morpholine oligomers and interferons. The paper discusses the most significant achievements in this sphere.

Ebola virus, representative of the Ebolavirus genus, Filoviridae family, causes severe hemorrhagic fever in humans, with lethality rates amounting up to 90 %. The members of Ebolavirus genus infect a broad range of mammalian cells. Recent studies indicate that entry of Ebola virus into cells requires a series of cellular protein interactions and molecular mechanisms, some of which are unique to filoviruses, while others are commonly used by all viral glycoproteins. The cellular factors deployed by filoviruses for their entry into permissive cells are defined incompletely. The aim of this review is to analyze peculiarity of the Ebola virus penetration into permissive cells at molecular level. The Ebola virus entry into cells is initiated by the interaction of viral glycoprotein with one or more receptors on the surface of host-cell. The main host-cell factors, involved in filovirus entry, are: attachment factors (cell lectins and human T-cell mucin 1 (TIM-1)), signaling factors (tyrosinkinase receptors and α5β1-integrin), and endolisosomal host-cell factors (cathepsins B and L and Niemann-Pick C1 protein. The study of the complex set of virus entry events provides potential avenues for the development of antiviral therapies against Ebola fever.