The review presents an analysis of the epidemiological and epizootiological situation on Crimean-Congo hemorrhagic fever (CCHF) in the Russian Federation in 2022. The incidence rate of CCHF registered in 2022 (59 cases) was 1.2 times higher as compared to 2021, however, below the long-term average annual values. The mortality rate was 10.2 %, which exceeds the indicators of long-term observations (in 2012–2021 – 3.2 %). Following epizootiological survey of stationary observation points, it was found that the number of Hyalomma marginatum imago in 2022, in general, corresponded to the average long-term indicators. CCHF virus isolates circulating in Russia in 2017–2022 belonged to the genetic lines “Europe-1” (V), “Europe-2” (VI), and “Europe-3” (VII). The ratio of CCHF virus genovariants in the population on the territory of the Russian Federation in 2017–2022 didn’t change. Based on the analysis of naturalclimatic factors, the forecast for the incidence of CCHF in the Russian Federation for 2023 has been made.

The review contains information on paleogenomic studies of the plague pathogen, Yersinia pestis, covering the prehistoric epoch, the periods of the first and second plague pandemics, epidemics and outbreaks of plague of the late XIX–XX centuries. We have summarized the data on the reconstruction of ancient Y. pestis genomes of the Late Neolithic, Bronze and Iron Ages, the Justinian Plague epidemic of the first plague pandemic, the Black Death epidemic and the subsequent epidemics of the second plague pandemic of the XIV–XVIII centuries, as well as on tracing the pathways of plague propagation waves in Eurasia and the course of plague agent evolution with the formation of a vector-borne transmission route with the help of arthropods. We present the results of our own research of Y. pestis genomes from the key sites of formation of etiological agents of the first and second plague pandemics in the Tien Shan Mountains, historical outbreaks in the Northern and North-Western Caspian sea region and other regions of Russia and adjoining countries in the late XIX–XX centuries. The paper discusses the areas of the Caucasus, Crimea, Northern Caspian, Siberia, and Tien Shan in the territory of Russia and neighboring states that are promising for national paleogenomic studies of plague.

The review reports on the secretion pathways of the main virulence factor of Vibrio cholerae, cholera toxin, both through the two-stage Sec-dependent type 2 secretion system and with the help of vesicles of the outer membrane of V. cholerae. The ways of toxin transfer into the host organism, depending on its form, are discussed. The well-studied free soluble cholera toxin is secreted extracellularly and transmitted in a GM1-dependent manner through cholesterolrich lipid rafts. The transfer of cholera toxin associated with vesicles has advantages over free toxin, because substances inside the outer membrane vesicles are protected from external proteases and host antibodies by the membrane that forms the vesicle. Vesicular transporting of cholera toxin into the target cell occurs via clathrin-dependent, caveolin-dependent and lipid raft-dependent endocytosis. The specific transport route is determined by the structure of the vesicles. Clathrindependent endocytosis is described for V. cholerae strains cultivated at low osmolarity of the medium, whose outer membrane vesicles contain the cholera toxin subunit A inside. Lipid raft-dependent endocytosis is characteristic of vesicles in which cholera toxin is located on the surface. In addition, endocytosis of V. cholerae outer membrane vesicles through structures known as caveolae is presented.

The aim of the review was to characterize the epidemiological situation on tick-borne rickettsioses (TR) in the Russian Federation in 2022 in comparison with the pandemic years of 2020–2021 and the pre-pandemic period of 2013–2019, to give the forecast for 2023. During 2013–2022, a pattern was observed in the incidence of rickettsiosis of the tick-borne spotted fever group (with the exception of Astrakhan spotted fever – ASF), that is also characteristic of most other natural focal infections (NFIs): a sharp decrease in registered incidence rates in 2020–2021 with the subsequent increase in 2022 almost up to pre-pandemic levels or even exceedance in some regions. The absence of a defining influence of the frequency of contacts of the population with vectors on the decrease in the incidence in the period of 2020–2021 and the rise in the value in 2022 confirms the registration-related nature of the changes. Given due attention to the problem of effective detection and reporting of NFIs, we expect the incidence of tick-borne rickettsioses to remain within the confidence intervals of long-term average values in most endemic regions in 2023. Relaxed vigilance to the problem of NFIs may lead to a decline in the reported incidence of Siberian tick-borne typhus in the Krasnoyarsk and Zabaikalsky Territories, Republics of Tuva and Khakassia, Novosibirsk and Amur Regions; reduction in the incidence of ASF in Astrakhan Region. The main issue in detecting and registration of the tick-borne rickettsiosis incidence, objective assessment and forecasting of the epidemic situation as regards this group of infections is conditioned by the lack of domestic certified diagnostic test kits for laboratory verification of rickettsioses. Close cooperation between epidemiologists and clinicians is required to establish and register cases of TR based on clinical and epidemiological data.

The review presents an analysis of the epizootic and epidemic situations on rabies in the Russian Federation in 2019–2021. During that period, there was a decrease in the activity of the epizootic process to the level of the 1990s characterized by overhunting of the fox, raccoon dog and corsac. The number of identified potentially hazardous areas declined by 20 %, and the number of sick animals registered in them decreased from 18 to 10. Since 2018, the share of domestic animals has prevailed over wild animals in the structure of animal incidence, and in 2021, the proportion of detected cases of rabies in wild animals was the smallest (37.9 %) over 11 years of observation (2011–2021). The leading role in maintaining the circulation of the rabies pathogen belonged to the fox, which accounted for 34.8–29.9 % of all animal cases in 2019–2021. The raccoon dog actively contributed to the circulation of the virus in the European part of Russia. Since 2012, a downward trend in the incidence of rabies among the population has been established (Tdw. = –9.5 %), the average long-term indicator was 5 cases per year. Dogs and cats that got involved into epizootic process predominated among the sources of hydrophobia – approximately 50 % of the cases. Poor compliance with the rules for keeping pets has led to an increase in human infection with rabies due to the animals in 2020–2021. In 2019–2021, the participation of bats in infecting humans with lyssavirus was established, which draws the attention to the need to study the role of bats in the circulation of lyssaviruses, primarily in the Far East. The risk of rabies infection persisted in almost all regions of the country. In the 21st century, natural foci of infection are ubiquitous in Russia. 

An analysis of brucellosis incidence in Russia in 2013–2022 and the data on genetic diversity of Brucella melitensis and Brucella abortus populations isolated in Russia in 1939–2022 are provided in the review. Over the past decade, the epidemiological situation in Russia has been characterized as unstable against the background of persistent unfavorable conditions for brucellosis in cattle and small ruminants. During the period of 2013–2022 (9 months), 4298 epizootic foci as regards brucellosis in cattle (89164 sick animals) and 371 as regards brucellosis in small ruminants (13569) were registered. The largest number of epizootic brucellosis foci was recorded in the North-Caucasian and Southern Federal Districts. In 2013–2022, on average, 327 cases of brucellosis among people were registered annually, the incidence rate per 100 000 of the population was 0.24. Up to 70–90 % of brucellosis cases were detected in the south of the European part of the country. A trend towards deterioration of the situation on brucellosis in Volga (Penza and Samara Regions) and Central (Smolensk, Voronezh and Tula Regions) Federal Districts is observed. There is a connection between the intensity of epidemic manifestations of brucellosis and the level of anthropurgic enzooty of territories. In 2022, 467 cases of brucellosis were reported (0.32 per 100 000 of the population), which is 42.8 % higher than annual average values over 10 years. In 2023, a measure of stability of incidence rates, by 20–25 % above average long-term values, is to be expected. Incidence of brucellosis in humans will be within the range of 380–410 cases (0.26–0.28 per 100 000 of the population). The results of genotyping of B. melitensis strains point to an increase in the proportion of isolates with an MLVA-profile characteristic of strains from enzootic as regards brucellosis countries of Middle East and North Africa over past 20–25 years, which can indicate importation (introduction) of the infection from these territories to Russia through small ruminants and/or biomaterial from them.

The aim of the review was to characterize the epidemiological situation on ixodic tick-borne borreliosis (ITBB) in the constituent entities of the Russian Federation in 2022, to forecast the development of the ITBB epidemic process in 2023 based on the analysis of its trends in the period of 2013–2022. In total, 7 264 cases of ITBB were registered in the Russian Federation in 2022, which is 1.9 times higher than the 2021-value. In all regions in 2022, after a sharp decrease in the level of registered morbidity during the “covid” phase of 2020–2021, there was an incidence raise to the pre-pandemic level. During 2013–2022, distinctive features of the trends in the development of the ITBB epidemic process in the territories of varying degree of epidemic hazard were retained. A downward tendency in the incidence rates was revealed in 14 out of 18 entities with a long-term average annual incidence (LTAA) of ITBB above 6.2 _{0 /0000}, with the exception of Moscow and the Kaluga Region, where a further increase in the incidence of ITBB is possible. In 6 out of 16 regions with LTAA _2013–2022 between 3.31 and 6.2 _{0 /0000}, an upward trend was observed, and in 8 – a decrease in morbidity. The trend towards an increase in morbidity was detected in 7 out of 21 entities with LTAA of ITBB from 1.21 to 3.3 _{0 /0000} and in 15 out of 26 regions with a low LTAA _2013–2022 (below 1.2 _{0 /0000}). The analysis of trends in the development of the ITBB epidemic process against the trends in changes in the frequency of contacts of the population with ticks, as well as calculations of the probable incidence rate allowed us to conclude that the incidence rate of ITBB in 2023 will range within the confidence intervals of long-term average annual values for the majority of the federal districts, with the exception of the Central Federal District, where an increase in the number of cases of ixodic tick-borne borreliosis is likely to occur, provided that the existing volumes of preventive measures are maintained and abnormal climatic phenomena absent. Effective control of the epidemic situation on the ITBB is attainable through preservation, and for such areas as Moscow, the Moscow Region, Voronezh, Kaluga, Orel, Ryazan, Penza and Rostov Regions, the Republic of Buryatia – increase in the volume of preventive measures, strengthening zoological and entomological monitoring of activity and structure of natural foci. There is an obvious need to develop algorithms for molecular-genetic monitoring of pathogens circulating in natural foci, and to focus attention onto the problems of diagnosis and prophylaxis of tick-borne transmissible infections.

The paper provides the results of analysis of the epizootiological and epidemiological situation on anthrax in the world in 2022, also, the forecast of incidence rates for the Russian Federation in 2023 is presented. In 2022, two cases of anthrax in farm animals and two cases of cutaneous form of infection in humans were registered in Russia, in the constituent entities of the North Caucasian Federal District: the Republic of Dagestan and the Stavropol Territory. The tense situation on anthrax was reported in the neighboring countries: Azerbaijan, Georgia, Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan, and Ukraine. Epizootics of infection with the highest number of affected farm and wild animals were recorded in the countries of Africa, Asia, North America and Europe. The incidence of anthrax among people in the far abroad (mainly in Africa and Asia) was mostly associated with consuming the meat of sick and fallen farm animals, contact with infected animals, animal products. The incidence of anthrax in animals and humans in the Russian Federation in 2023 will largely depend on the scale of coverage with specific immunization of susceptible animals and persons at risk of infection and, given the strict implementation of comprehensive surveillance measures, will be limited to the registration of potentially possible single cases of infection.

The paper presents a hypothesis that the most probable cause of death of the ancient world Indus (Harappa) civilization was the epidemic of Asiatic cholera. A brief description of the Indus civilization that existed for two millennia (3300–1300 BC) is given. It is shown that the previously described factors for the decline of the thriving Indus civilization (climate change, shallowing of the Indus river and reduction in floods, catastrophic floods, drought, economic crisis, etc.) do not provide a consistent and comprehensive explanation of the causes of its death. Meanwhile, the natural environment and peculiarities of agriculture of the Indus civilization (annual floods affecting not only fields, but also sewage systems) created ideal conditions for the spread of water-borne cholera. The evolution of the Asiatic cholera agent is discussed. The results of paleogenomics study of this pathogen and their significance for the reconstruction of evolutionary events are briefly reviewed. The stages of evolution of Vibrio cholerae of the classical biovar are described, and possible mechanisms for the preservation of the pathogen during inter-epidemic period are considered. It is demonstrated that aside from cholera, other catastrophic, destructive epidemics are recorded in the history of mankind.

The aim of the study was to experimentally substantiate the possibility of using a nutrient medium based on enzymatic fibrin hydrolyzate in order to obtain specific components of chemical cholera vaccine: cholerogen-anatoxin and O-antigen.
Materials and methods. We used production strains of Vibrio cholerae 569B and V. cholerae M-41. Submerged low-volume cultivation was carried out in a laboratory fermenter for 8 hours, with automatic maintenance of cultivation parameters and feeding with glucose on the nutrient medium based on enzymatic fibrin hydrolyzate, containing (1.0±0.1) g/l of amine nitrogen, pH being (8.0±0.1). Cholerogen-anatoxin and O-antigens were obtained from detoxified formalin-treated centrifugates of culture liquids. The specific activity of V. cholerae antigens at the stages of cultivation and isolation was determined applying immunochemical methods. The preparation of the finished dosage form of the cholera vaccine and the coating of the tablets with an enteric coating was carried out in accordance with the regulatory documentation.
Results and discussion. It has been shown that cultivation on the medium based on enzymatic fibrin hydrolyzate provides a stable growth of the biomass of V. cholerae production strains with a high level of specific activity of antigens. Comparative analysis of the main properties of the finished dosage form of laboratory batches with a commercial batch of chemical cholera vaccine has demonstrated compliance with the requirements of regulatory documentation. The results obtained has led us to conclusion that it is feasible to use the nutrient medium based on enzymatic fibrin hydrolyzate for cultivating production strains and obtaining specific components of the cholera vaccine.

The aim of the study was to characterize mono- and mixed infection with causative agents of vector-borne infections in Dermacentor reticulatus ticks inhabiting one of the anthropourgic foci of the Tomsk Region.
Materials and methods. D. reticulatus ticks were collected from vegetation “on the flag” in the forest park zones of the southern part of Tomsk in August and September, 2020–2021. To isolate nucleic acids from homogenates of mites and subsequent PCR diagnostics, kits of the RealBest series (“Vector-Best”, Novosibirsk) were used. 184 individual samples of nucleic acids were examined for the presence of molecular-genetic markers of tick-borne encephalitis virus (TBEV), pathogenic borrelia, babesia, rickettsia, anaplasma, and ehrlichia.
Results and discussion. The spectrum of pathogens detected through PCR assay of ticks collected in one of the anthropurgic foci of the Tomsk Region in 2020 and 2021 includes TBEV, pathogenic borrelia, rickettsia, and babesia. The highest rate of D. reticulatus infection has been established in relation to candidate pathogens of tick-borne rickettsioses (Rickettsia sp.) and babesioses (Babesia sp.). The overall frequency of co-infection in D. reticulatus was 12.88 %. Seven different associations of pathogens infecting D. reticulatus have been identified. The majority (88.24 %) of the detected cases of mixed infection were rickettsia associations. Double infection has been registered in 94 % of the total number of mixed variants. Markers of four tick-borne infection pathogens simultaneously (Rickettsia species DNA, Babesia species DNA, Borrelia burgdorferi s.l. DNA and TBEV RNA) have been found in one sample. Changes in areal of the D. reticulatus against the background of an increase in their numbers, determines the need to analyze the epidemiological significance of the ticks of this species in combined foci of tick-borne infections, especially in the zone of sympatry with ixodic ticks of other species.

The acquisition of new mobile genetic elements contributes to the genetic diversity of Vibrio cholerae strains. An important role in this process belongs to the genetic material obtained from phages.
The aim of this work was to identify phage-induced PLE islands in strains of V. cholerae O1 serogroup and to determine the resistance of isolates with and without those mobile genetic elements to the lytic activity of the diagnostic cholera El Tor bacteriophage.
Materials and methods. Whole genomes nucleotide sequences of toxigenic and non-toxigenic V. cholerae O1 strains presented in the NCBI GenBank were used for the work. Bioinformatic analysis was performed using the BLAST algorithm, MEGA X (or BioEdit v. 7.0.9.0). The test with phages was carried out according A. Gratia technique.
Results and discussion. The analysis of 39 toxigenic strains imported to the territory of the Russian Federation and neighboring countries has revealed one strain of V. cholerae O1 of the classical biovar containing the PLE5 island, and 13 strains of V. cholerae O1 of the El Tor biovar containing the PLE4 island. PLE islands have not been found in non-toxigenic strains. It is shown that strains with PLE4 belong to V. cholerae O1 genovariants of the El Tor biovar and have the ctxB1 gene allele. Isolates with this mobile element caused sporadic cases of the disease in 1994–1999, as well as cholera outbreaks in the Russian Federation (in 1993–1994, in 1998 – Dagestan, and 1993 – Tatarstan) and Ukraine (1994–1995). It has been suggested that, perhaps, the presence of the PLE4 island makes a certain contribution to the resistance of V. cholerae O1 strains of the El Tor biovar to the diagnostic cholera El Tor phage (55.6 % of phage-resistant isolates were detected), but there are other mechanisms that have not yet been identified. Thus, the data on the presence of new mobile genetic elements in the genome of earlier imported toxigenic strains of V. cholerae O1, biovar El Tor have been obtained, which expands information about their genetic organization.

The risk of importation of infectious diseases is an urgent threat to sanitary and epidemiological well-being of the population, both at the level of individual countries and interstate associations, and globally. The territory of any country has a backdrop of hazards; therefore, the aim of the work was a comprehensive assessment of risk of infectious disease importation onto the territory of Russia for early and effective response to emerging biological threats.
Materials and methods. We used information on the structure of passenger traffic and the number of persons arriving in Russia according to the portal of the Unified Interagency Information and Statistics System. The data on the incidence of infectious diseases which require measures on sanitary protection of the territory of Russia is provided according to the official regional websites of WHO, regional Centers for Disease Control and Prevention (CDC), Ministries of Health of the respective countries. The risk of importation of infectious diseases was estimated in points in compliance with an original methodology developed with the participation of the authors.
Results and discussion. We have determined the structure of the passenger traffic across the borders of Russia and the most relevant infectious diseases that pose a risk of importation, as well as the countries, from where the importation of infections is most likely to occur. It is outlined that importation of dengue fever and cholera from the Southeast Asian region, dengue from the Western Pacific region, cholera and malaria from the Eastern Mediterranean region, cholera, malaria and dengue from the American and African regions is most probable. 

The aim of the work was to study interaction of Yersinia pestis with soil nematodes isolated on the territory of the Gorno-Altai high-mountain plague focus.
Materials and methods. We used the fluorescent Y. pestis strain KM2083, a derivative of the natural strain of the 4.ANT phylogenetic line, the antique biovar of the main subspecies, and a nematode culture isolated in the same area of the Gorno-Altai plague focus. The taxonomy of nematodes was determined by the region of the 18S rRNA gene; phylogenetic analysis was performed using the Maximum Likelihood method based on the Tamura-Nei model in the Mega 7.0 software. The interaction of the Y. pestis KM2083 strain and the nematodes was studied during cultivation on a solid NGM agar medium. Nematodes were observed using microscopes Stemi-2000C (Carl Zeiss, Germany) and Axio Imager Z2 (Carl Zeiss, Germany).
Results and discussion. It has been established that the nematodes from the Gorno-Altai high-mountain plague focus used in the work belong to the genus Panagrolaimus. Cultivation of nematodes on the lawn of the Y. pestis strain of the main subspecies of antique biovar, the 4.ANT phylogenetic line for 24 hours did not lead to a reduction in the lifespan of nematodes compared to the control sample, which indicates the absence of toxicity of the used strain towards Panagrolaimus nematodes. On the cuticle of nematodes, the formation of a biofilm in the genital area and tail has been noted, and accumulations of fluorescent cells of the plague pathogen observed in the digestive tract. The data obtained can indicate the ability of nematodes to carry the plague pathogen in the soil biocoenosis.

The aim of the work was to determine the effective ultraviolet (UV) doses required for the disinfection of surfaces contaminated with the SARS-CoV-2 coronavirus using a low-pressure mercury lamp.
Materials and methods. To carry out prompt disinfection of surfaces, a specially designed source of UV radiation with a power of 7.5 W at a wavelength of 254 nm in the form of a portable flashlight was employed, which has a high efficiency of UV radiation output and the possibility of long-term autonomous operation from a compact battery. In the studies, a suspension culture of the SARS-CoV-2 coronavirus with biological activity of 5.3∙10⁶ PFU/ml was used. The objects of testing were plastic Petri dishes (disposable) and office paper (grade C, density 80 g/m² ).
Results and discussion. Doses of UV radiation that provide disinfection of surfaces contaminated with the COVID-19 pathogen with an efficiency of 99.0 % (paper) to 99.95 % (plastic) have been determined. The results obtained make it possible to recommend a portable UV irradiator for use in the practice of preventive measures to combat the spread of the disease caused by the SARS-CoV-2 coronavirus.

In Kazakhstan, foot-and-mouth disease (FMD) outbreaks were recorded in 2011–2013 in the southern and eastern regions where FMD vaccination is in place. In January 2022, in Kiikty village of the Shetsky district, Karaganda Region, Republic of Kazakhstan, cases among cattle clinically similar to foot-and-mouth disease were reported.
The aim of the research was to establish the cause of the disease and to perform the typing of the pathogen.
Materials and methods. Samples from sick animals were tested using PCR, sequenced and typed in compliance with the protocol developed by the International Office for Epizootic Diseases (OIE).
Results and discussion. A cytopathogenic agent has been isolated from the BHK-21 cell culture, identified through real-time RT-PCR and electron microscopically as FMD virus. Molecular genetic studies have revealed that the infection of cattle in the Karaganda Region was caused by the FMD virus circulating in the territory of the countries bordering Kazakhstan (China, Russia, Mongolia) and belonging to type O, topotype ME-SA, genetic line Ind-2001. FMD virus isolated in Kazakhstan is genetically related to the FMD line from Asia and is a new FMDV genotype for Kazakhstan, assigned to the ME-SA topotype of the Ind-2001 genetic line. This study once again proves the need for continuous genetic typing of FMD viruses to improve the effectiveness of preventive measures.

The aim of the work was to study specific systemic effect of sulfate-reducing bacteria of the genus Desulfovibrio on organism systems through creating an experimental model of intragastric bacterial invasion against the background of dysbiotic conditions of rodent gastrointestinal tract.
Materials and methods. The experimental study was conducted on Wistar rats. Intestinal dysbiosis was modeled with the help of antibiotics, amoxicillin and metronidazole. Typical strain Desulfovibrio desulfuricans subsp. desulfuricans VKM B-1799^T was used as an infectious agent.
Results and discussion. As a result of the experiment performed, during the period of acute infection (on day 15 of the experiment), a direct correlation between the concentration of the injected D. desulfuricans VKM B-1799^T bacteria suspension and the serum iron level was observed: the higher the infectious agent dose, the lower the serum iron concentration. During the phase of remote effects (day 38 of the experiment), the inverse correlation between the concentrations of D. desulfuricans VKM B-1799^T in the intestines of rodents was revealed: when the concentration of the infecting agent increased from 10³ CFU/g and higher, the iron level decreased from 43.5 μmol/l to 38.5 μmol/l. When comparing the level of transferrin and unsaturated iron binding capacity (UIBC), an increase in those parameters was observed in all groups of rats both during the period of acute infection and the period of long-term effects, and the percentage of transferrin iron saturation decreased, indicating the occurrence of iron deficiency against the background of exposure to the infectious agent. Intestinal dysbiosis promotes colonization by opportunistic flora, including Desulfovibrio sp. Changes in the iron metabolism markers in experimental animals against the background of D. desulfuricans VKM B-1799^T infestation above 10³ CFU/g and the ability of this microorganism to bind iron into an unavailable form suggest that the bacteria Desulfovibrio sp. are one of the key etiological factors of iron deficiency anemia.

The tactics of activities of the specialized anti-epidemic team (SAET) of the Rospotrebnadzor on the territory of the Republic of Crimea has been determined by the conditions of emergency situation of sanitary-epidemiological and natural character.
The aim of the work was to analyze the features and effectiveness of the functional response of the Rospotrebnadzor SAET to the dynamics of epidemiological risks caused by emergency of combined nature in the Republic of Crimea in 2020–2021.
Materials and methods. We used report materials of the Rospotrebnadzor SAET; information materials of the Interregional Rospotrebnadzor Administration in the Republic of Crimea and the Federal city of Sevastopol; “Coronavirus Monitor” service data.
Results and discussion. Tactical decisions on the work of the SAET on the territory of the Republic of Crimea had the stage-by-stage nature. In the event of a complication of the epidemiological situation on the new coronavirus infection, a mobile group of the SAET was involved. Together with specialists from the Plague Control Station of the Republic of Crimea, it conducted 211 148 studies of clinical material to detect SARS-CoV-2 RNA using PCR during the period of 2020–2021. In response to the emergence of additional risks caused by the consequences of a dangerous meteorological phenomenon, the group of SAET specialists was reinforced and mobile complex (MС) of the SAET was deployed. During the entire course of work, a prolonged target rotation of personnel was implemented in order to provide for adequate laboratory support for monitoring upon epidemiological indications in accordance with the nature of emerging risks. That tactics of operation made it possible to conduct 18 591 screening studies of clinical material for acute respiratory viral infections (ARVI), natural-focal and acute intestinal infections (AII), as well as the study of 280 water samples for cholera. Introduction of the sequence of operational procedures adapted for work in emergency situations resulted in isolation of 10 Vibrio cholerae O1 ctxA^{–</sup tcpA–/em>  strains from water bodies. The phased involvement of the mobile group of SAET specialists, and later the MC of the SAET, in combination with the consistent operational target rotation of personnel in order to provide adequate laboratory support for monitoring studies, determined the tactical features of the SAET functioning. Prompt investigation, substantiation of potential and response to realized (actual) epidemiological risks associated with the extraordinary situation made it possible to prevent complications of the epidemiological situation in the territory of the tourist cluster of the Russian Federation.}

Hemorrhagic fever with renal syndrome (HFRS) is registered in various geographical regions of the Russian Federation and occupies one of the leading positions among natural-focal human diseases in Russia.
The aim of the study was to assess the epidemiological situation on HFRS in the Rostov Region.
Materials and methods. Laboratory diagnostics of field material (samples from wild rodents) for the presence of antigens of HFRS pathogens and screening of blood sera from donors, residents of the region, for the presence of class G antibodies to viruses that cause HFRS were carried out by enzyme immunoassay during 2020 and 2021.
Results and discussion. Hantavirus antigens were identified in five administrative districts of the Region in 2020, infection with HFRS virus in small mouse-like rodents was 7.1 %. In 2021, spontaneous infection of carriers was detected in 2.8 % of the samples, found in four districts of the Region. The presence of the virus markers was recorded in populations of five species of mouse-like rodents: house mouse, wood mouse, common vole, small wood mouse, yellow-bellied mouse. Among healthy population, class G antibodies were registered in 6.8 % in the surveyed territories in 2020, and 4.5 % in 2021. Detection of virus markers in carriers and the presence of a natural immune layer of the population as regards HFRS agents suggest the existence of a natural HFRS focus in the Rostov Region.

Coronaviruses (family Coronaviridae, genera Alphacoronavirus and Betacoronavirus) are the causative agents of respiratory, intestinal and neurological diseases in humans and animals. Natural reservoirs of coronaviruses include bats, rodents and insectivores, however, the circulation of coronaviruses among rodents and insectivores in the Russian Federation has been unexplored.
The aim of the study was to investigate the diversity of coronaviruses among rodents and insectivores co-inhabiting natural biotopes.
Materials and methods. Rodents (68 specimens) and shrews of the genus Sorex (23 specimens) were caught in a limited forest area not exceeding 1.5 sq. km, in the vicinity of Novosibirsk. All samples were screened using reverse transcription polymerase chain reaction followed by sequencing.
Results and discussion. Four distinct coronaviruses have been detected in four species of small mammals. Rodent-borne coronaviruses were classed within subgenera Embecovirus, genus Betacoronavirus, and demonstrated host-associated phylogenetic clustering. The level of homology between the new RNA isolates from red-backed vole (Myodes rutilus), root vole (Microtus oeconomus) and field mouse (Apodemus agrarius) is 85.5–87.7 %. The nucleotide sequences of Siberian coronavirus isolates are closely related (>93 % homology) to previously published sequences in each of the carrier groups found in Europe and China, which suggests their common evolutionary origin. The coronavirus identified in the common shrew (Sorex araneus) belongs to the genus Alphacoronavirus, but is significantly different (>36 % difference) from earlier identified strains included in the genus. It has been shown that different coronaviruses co-circulate in a limited area among rodents and insectivores.

The aim of the study was to perform the epidemiological and epizootic analysis of the situation on brucellosis in the Kyrgyz Republic.
Materials and methods. When assessing the incidence of brucellosis in the Kyrgyz Republic over the period between 1983 and 2021, official data of the Republican Center of Quarantine and Particularly Dangerous Infections, the Department of Disease Prevention and State Sanitary and Epidemiological Surveillance of the Ministry of Health of the Kyrgyz Republic, the State Inspectorate for Veterinary and Phytosanitary Safety of the Kyrgyz Republic, and the National Statistical Committee of the Kyrgyz Republic were used. The obtained materials were processed applying Microsoft Excel 2010.
Results and discussion. It is shown that the adverse situation on brucellosis among the population persists in the country: during the study period, the average incidence rate was 29.3 cases per 100 000 of the population. It is associated with constantly occurring epizootics among farm animals, especially small ruminants, which are the main source of human infection. A pronounced summer seasonality of brucellosis cases is noted, due to the participation of people in lambing and calving of animals. Since 2008, there has been a gradual decrease in the incidence of brucellosis among people, after the start of systematic mass vaccination against brucellosis in small ruminants. It is necessary to carry out the entire complex of anti-brucellosis measures and social mobilization of the population to stabilize the epidemic and epizootic situation in the country. The realization of the task will be facilitated by the development of the State Program to combat brucellosis for the interdepartmental integration of all efforts to prevent this dangerous infectious disease.