The aim of the study was to clarify the boundaries of the Central Asian natural plague focus of Kazakhstan and the modern boundaries of the areal of the great gerbil (Rhombomys opimus) in order to improve epizootiological monitoring and increase the effectiveness of preventive (anti-epidemic) measures.Materials and methods. Data from the epizootiological monitoring of the great gerbil populations in 14 autonomous foci of the Central Asian desert natural plague focus in the Republic of Kazakhstan between 2010 and 2020 were used for the analysis. An epizootiologic survey of an area of 875350 km2 was carried out. When processing the data, epidemiological, epizootiological, statistical research methods, as well as GIS technologies were used.Results and discussion. An increase in the total area of the Central Asian desert natural plague focus of the Republic of Kazakhstan by 79710 km2 (9.98 %) has been established for the period of 1990–2020. It is noted that the change in the area of plague-enzootic territory was a consequence of the ever changing areal of the main carrier of plague pathogen – the great gerbil – under the influence of climatic and anthropogenic factors. The most significant changes were found in the southeastern part of the plague-enzootic territory, including those for the Betpakdala (50 %), Balkhash (34.3 %), Taukum (13.3 %) and Mojynkum (0.32 %) autonomous foci. The area of the Aryskum-Dariyalyktakyr autonomous focus decreased by 2100 km2 (4 %). In 2000–2002, new Alakol’sky and Ili intermountain autonomous foci with a total area of 26759 km2 were discovered. It is shown that due to the regression of the Aral Sea, the areal of the great girbil expanded and the area of the North Aral and Kyzylkum natural plague foci increased by 10500 km2 (29.2 %) and 560 km2 (0.4%), respectively. The areas of the Aral-Karakum and UralEmba desert autonomous foci, on the contrary, decreased by 2000 km2 (2.6 %) and 12300 km2 (17.6 %), respectively. Passportization and landscape-epizootiologic zoning of the territory of the Central Asian desert natural plague focus of the Republic of Kazakhstan has been completed.

The aim of the study was to improve epizootiological monitoring and increase the effectiveness of preventive (anti-epidemic) measures for camel plague control in Kazakhstan.Materials and methods. We used the data on epizootiological and epidemiological monitoring in natural plague foci of Kazakhstan, long-term measurements and indicators for the period of 2000–2020 of the anti-plague and veterinary services of the Republic for the analysis. To process the evidence, epidemiological, epizootiological, microbiological, and statistical research methods, as well as GIS technology were applied.Results and discussion. The number of camels has increased by 2.2 times in Kazakhstan over the past 20 years. Where there were 98.2 thousand heads in 2000, it amounted to 216.4 thousand heads in 2020. Over the past 10 years, 152 camels died of unknown causes in the focal area of the country, but laboratory tests for plague turned out negative. According to the hazard criteria, the territory of the country has been conditionally divided into three zones: five regions with a high degree of hazard with a total area of 953.15 sq. km, five regions with medium degree of hazard with a total area of 1230.72 sq. km, and with a low degree of hazard – four regions and three cities of republican significance with a total area of 541.1 sq. km. Constant epizootiological monitoring over plague in camels is a necessity for the system of preventive measures.

Background. Epidemiological and epizootological monitoring of natural plague foci requires an integrated approach to solving problems, taking into account the phenotypic and genetic variability of Y. pestis and zoning of natural plague foci. The introduction of a new molecular genetic methodology aimed at studying the genomic polymorphism of the plague pathogen provides reliable results for the differentiation of not only groups, but also individual strains.The aim. To determine the genotypes of the plague microbe from different autonomous foci of the Republic of Kazakhstan.Materials and methods. 105 strains of Y. pestis isolated from various natural plague foci of Kazakhstan in 1951–2015 were studied. The phenotypic properties of the strains were studied using standard microbiological methods. A polymerase chain reaction (PCR) was used to detect fragments of the cafl, pst and YPO2088 genes. Multilocus variable number tandem repeat (VNTR) analysis (MLVA) was performed for 25 VNTR loci.Results. The phenotypic properties of the strains were preliminarily studied and the strains of the plague microbe were tested for specificity using the Pest-Quest test system (Kazakhstan). The PCR study confirmed the species-specific affiliation of Y. pestis strains. A variety of strains with typical phenotypic characteristics was revealed. MLVA for 25 key loci (MLVA25) revealed that the studied strains of the plague microbe are phylogenetically closest to the Mediaevalis biovar representatives. A phylogenetic tree of the studied strains has been obtained. It was found that 9 genotypes circulate on the territory of Kazakhstan, and their distribution in certain natural plague foci was determined.Conclusions. The resulting clustering indicates the relationship between the strain groups obtained on the dendrogram by the MLVA25 method and the territories of certain natural plague foci.

The study of freshly isolated cultures is necessary to form an objective idea of the properties of plague microbe natural populations. The analysis of the levels of investigating the properties of strains has been carried out and the characteristics of Yersinia pestis in Kazakhstan are presented. The results of studying the phenotypic and genetic properties of plague microbe natural strains are provided. Following the epizootiological survey of natural plague foci, the museums of live cultures at plague control stations annually receive strains of plague pathogen, which are transferred to the National Collection of Microorganisms of the National Scientific Center of Particularly Dangerous Infections (NSCPDI). One of the main points of Y. pestis strains analysis is the determination of their typicality/atypicality. The study of strains begins at the moment of their isolation by anti-epidemic units. The primary identification of strains is carried out in laboratories of anti-epidemic units by morphology, sensitivity to plague and pseudotuberculosis bacteriophages, fermentation of glycerol, rhamnose and sucrose. In the laboratories of plague control stations and departments, fermentation of maltose and arabinose, denitrification, amino acid requirements, virulence, sensitivity to antibiotics are additionally investigated. Analysis of strains virulence includes determination of calcium dependence, the presence and amount of F1, pesticinogenicity and sensitivity to pesticin 1 and virulence for white mice. The assessment and preservation of the collected gene pool in the NSCPDI National Collection includes various activities, one of the main ones is an in-depth study of all features using standard microbiological methods, molecular methods for complete identification and creation of a data bank containing information about the genome of strains at different intensity of the epizootic process. The NSCPDI has a digital database on the registration and movement of strains, equipment for molecular research. The collection evaluates properties, systematizes information, and ensures the viability of plague pathogen strains for longterm storage.

This review provides a comprehensive overview of the genetic diversity and epidemiological potential of Yersinia pestis in Kazakhstan’s natural plague foci, emphasizing the link between genotypic variation and outbreak capacity. Integrating historical epidemiological records with contemporary microbiological and genomic data (including PCR, VNTR/MLVA, SNP analysis, and whole-genome sequencing), we evaluate core and accessory genome variations. The data reveal substantial regional heterogeneity. High-risk desert foci (Caspian and Aral regions) are dominated by the Medievalis biovar, including atypical genovariants lacking canonical markers. Conversely, high-mountain foci (Sarydzhaz, Talas) harbor the Antiqua and Talas biovars, primarily linked to enzootic circulation. Notably, the Ili River focus exhibits extreme genomic variability, featuring strains with plesiomorphic traits. Furthermore, the widespread distribution of mobile elements like the cryptic plasmid pCKF suggests significant horizontal transfer contributing to pathogen adaptation. Ultimately, Central Asian plague dynamics are driven by complex evolutionary and ecological interactions. Given climate change and expanding human–wildlife interfaces, continuous genomic and ecological surveillance is essential for the early detection of high-risk Y. pestis genovariants and improving public health preparedness.

It is well known that the earth's climate changes that occur as a result of global climate change are changing the biosphere of our planet as a whole. As a result, many animal species change their geographical ranges, seasonal activity, migration patterns, abundance and interaction with other species, including microorganisms, the facts of which are observed in the deserts of Kazakhstan. The main carrier of the causative agent of the plague in the desert natural focus of the Betpakdala plague of Kazakhstan is the great gerbil (Rhombonus opimus), where the plague epizootic was first discovered in 1959, the area of which was then 30.0 thousand. km² until 1990. Due to the rapid industrial development of the Betpakdala desert, the impact of global climate change on earth and other factors over the past 30 years, the area of this natural plague outbreak has increased by 50.12% (60.14 thousand km²) in the northern direction due to the biological transformation of the area of the main carrier, which led to the expansion of plague epizootics among rodents. At the same time, the plague microbe was also involved in the transformation process, increasing its natural area of the pistil (the area of distribution of the microbe), which increased the risk of infection of people with plague infection. The paper presents our results of epizootological monitoring for the period 2009–2022 (50.0 thousand km²) and laboratory studies of 522376 samples of field material for plague. The structure of the focus was shown, and the reason for the expansion of the settlement area of the rodent population was revealed. The number of sectors with different levels of epidemic danger and epizootic activity were determined, and the main phenotypic and genotypic properties of Yersinia pestis strains circulating in this natural plague focus were also given.