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In the last 10 years, scientists' interest in the horsepox pathogen has increased sharply due to the obtaining of its chimeric copy and the discussion of whether it was used to create early smallpox vaccines and the dangers of technologies that allow the restoration of extinct pathogens of dangerous infections.The aim of the work is to summarize the materials on modern studies of the horsepox virus.The source base of the study is English-language scientific literature available via the Internet.The research method is an analysis of scientific sources on horsepox from the general to the specific. We considered the area of distribution of the virus, its epidemiological danger, phylogenetic relationship, data on the sequencing of the horsepox virus genome and the likelihood of its use in the creation of the first vaccines, as well as obtaining its chimeric copy, on the basis of which a new smallpox vaccine was created – TNX-801.Results and discussion. The horsepox virus belongs to the poxvirus family, the orthopoxvirus genus. Classical horsepox has previously been reported only in Europe (France), Mongolia, and Kenya. The complete nucleotide sequence of the horsepox virus genome MNR-76 isolated in Mongolia has been determined. In addition to genes common to all orthopoxviruses, it includes intact genes specific only to this virus, the homologues of which are fragmented in the genome of other orthopoxviruses. Phylogenetic analysis of a number of orthopoxviruses was performed and a phylogenetic tree was constructed based on the conserved central region of the genome and some of the more variable terminal regions. The data obtained indicate that horsepox virus is most closely related to vaccinia virus and rabbitpox virus strains. Although horsepox is currently considered extinct, its pathogen may persist in unknown reservoirs. The data on the sequencing of the horsepox virus genome, strain MNR-76, suggest that horsepox virus could have served as the basis for the first smallpox vaccines. A chimeric copy of the horsepox virus was obtained using synthetic biology, which was used to create a new smallpox vaccine, TNX-801. On its basis, a recombinant vaccine against SARS-CoV-2 was constructed. The restoration of "extinct viruses" using synthetic biology methods has led to intense debates about the benefits and risks of such research.Conclusion. It cannot be ruled out that the use of modern genetic engineering technologies may lead not only to the development of effective vaccines, but also to the production of new orthopoxviruses pathogenic for humans and animals, or to the reintroduction of smallpox, which is especially dangerous in the context of the virtual absence of smallpox immunity in the population and international control over experiments in the synthetic biology of dangerous pathogens.

Relevance. After smallpox eradication, in conditions of population immunity to orthopoxviruses absence, Monkeypox virus became most significant orthopoxvirus, pathogenic for humans. Therefore the generalization of data on the areas of infection outbreaks, human diseases and methods of prevention and treatment of monkey pox is important task. Aim. To characterize the problem of monkeypox in the world based on an analysis of foreign scientific publications over the past 20 years. Materials and methods. The work used publications presented in the main international medical information databases PubMed, Web of Science, Embase, etc. To analyze the publications, the analytical epidemiological method was used. Results and discussion. Monkeypox virus, obtained and identified in 1958, by genetic and phenotypic differences divides on two clades: West-African with lethality 3.6% and Central-African (Congo Basin) with lethality 10%. Monkeypox virus transmission to men happens in two ways, either from animal-to-human or human-to-human. Monkey pox is endemic only on African continent, but In 2003 year the first outbreak, numbering 47 confirmed cases, was occurred in non-endemic country – USA and the largest monkeypox outbreak began in Nigeria in September 2017 year and continue to the present. Comparison of the genome sequences of strains, isolated from patients in non-endemic countries, showed, that it genetically close to West-african strains, belong to II clades and were descended from a common ancestor. Many cases of disease in humans in the current outbreak have been traced to sexual transmission especially among men, who identify ourselves as gay or bisexual. The basis method for identification of agent in present time is PCR-RT targeting on the tumor necrosis factor (TNF) receptor gene. Usually monkeypox of human is mild, self-limiting disease. The symptoms of monkeypox are varied and non-specific. One of the most frequently observed clinical symptoms is lymphadenopathy. Most patients recover during some weeks. However, specific antiviral treatment – tecovirimat (S-246) and brincidofovir (CMX-001) – may be used for seriously ill or immunocompromised individuals. For prophylactic disease in present time are use vaccines JYNNEOSTM, ACAM2000R and Aventis Pasteur (APSV). Conclusion. General vaccination against monkeypox don't develop accordingly to modern recommendations WHO. Ring vaccination is recommended to conduct for suppression of spread virus in nidus of infection among population. Timely international coordination is needed to prevent the global spread of a disease with epidemic potential.