Bekbolat Usserbayev

Orthopoxviruses are zoonotic DNA viruses of continuing public health importance, as highlighted by recent global mpox outbreaks. The high antigenic similarity among orthopoxviruses enables cross-reactive immune responses but complicates the development of serological diagnostic systems for serosurveillance, assessment of previous exposure, evaluation of vaccine-induced immunity, and species differentiation. This review summarizes current knowledge regarding the structure, biological functions, and diagnostic and vaccine potential of major orthopoxvirus recombinant antigens. Particular attention is given to the genomic organization of Orthopoxvirus, differences between intracellular mature virion (IMV) and extracellular enveloped virion (EV) forms, and the characteristics of key antigens, including A29, M1, H3, A35, and B6. Comparative phylogenetic analyses demonstrated a high degree of conservation among structurally important orthopoxvirus proteins while also identifying variable regions potentially relevant for differential diagnostics. Available evidence indicates that IMV-associated proteins are primarily involved in virus neutralization, whereas EV-associated antigens contribute mainly to limiting viral dissemination. Consequently, multicomponent antigen strategies combining IMV- and EV-associated proteins appear to provide the greatest potential for the development of effective serological assays and next-generation subunit vaccines. Overall, rational antigen selection should be based on integrated evaluation of structural, functional, and immunological properties to optimize orthopoxvirus diagnostic and vaccine platforms.

Background: The simultaneous circulation of highly pathogenic avian influenza (HPAI) H5N8 (clade 2.3.4.4b) and virulent Newcastle disease virus (NDV) genotype VII creates a cumulative risk for the poultry industry, rendering monovalent vaccination insufficient. This study aimed to develop and evaluate a combined inactivated vaccine against AIV H5N8 and NDV genotype VII based on local endemic strains. Methods: The vaccine was formulated as a water-in-oil emulsion (30:70) using Montanide™ ISA 78 VG. Evaluation included physicochemical characterization, safety assessment in chickens, immunogenicity evaluation via the hemagglutination inhibition (HI) test, and protective efficacy following challenge with virulent isolates. Results: The formulation demonstrated high stability and complete safety without adverse reactions. By 28 days post-immunization, the vaccine induced a robust, balanced humoral response with antibody titers reaching 9.10 ± 0.23 log₂ against NDV and 9.00 ± 0.26 log₂ against AIV, indicating no antigenic interference. Upon challenge, the vaccinated group exhibited 100% clinical protection and survival, compared to 100% mortality in controls. Furthermore, vaccination significantly reduced viral shedding, limiting horizontal spread. Conclusions: The developed combined inactivated vaccine demonstrates high safety, stability, and protective efficacy. It represents a promising candidate for comprehensive specific prophylaxis in endemic regions, effectively limiting horizontal pathogen transmission and mitigating economic losses in poultry production.

Salmonella enterica bacteriophages are increasingly studied for bacterial biocontrol and applied microbiology. However, reliable downstream characterization depends strongly on how the phage material is purified and concentrated. This study compared five preparation strategies for a Salmonella bacteriophage: sucrose density gradient centrifugation, cesium chloride gradient centrifugation, ultrafiltration followed by lyophilization, ultrafiltration followed by ammonium sulfate precipitation, and ultrafiltration followed by trichloroacetic acid precipitation. The preparations were assessed for infectious phage recovery, total protein concentration, SDS-PAGE protein profiles, an exploratory molecular weight-based comparison with a reference phage dataset, and targeted real-time PCR screening for selected virulence-associated determinants. Ultrafiltration followed by ammonium sulfate precipitation gave the highest infectious phage recovery among the infectivity-preserving workflows and produced a consistent eight-band SDS-PAGE profile. Trichloroacetic acid precipitation produced a similar banding pattern but was considered mainly a protein precipitation method because of its denaturing effect. Cesium chloride gradient centrifugation gave the most complex SDS-PAGE profile, while ultrafiltration followed by lyophilization gave the least resolved one. Several bands fell within the molecular-mass ranges reported for proteins of related Salmonella phages, but matching by molecular mass alone cannot identify the proteins, which would require LC-MS/MS. Targeted real-time PCR did not detect sopE , sspH1 , sseI , or sopE2 . Under the conditions tested, ultrafiltration followed by ammonium sulfate precipitation gave the highest infectious recovery and a consistent SDS-PAGE pattern; these results describe how the workflows behaved here rather than showing that one method is generally superior. Key points: • Five workflows were compared for Salmonella phage purification. • Ammonium sulfate precipitation gave the highest infectious recovery. • Selected virulence-associated genes were not detected by qPCR.

The Coronaviridae family represents a broad group of RNA-containing viruses that infect humans and animals. This family belongs to the order Nidovirales and is divided into four main genera: α-CoV, β-CoV, γ-CoV and δ-CoV. It is particularly noteworthy that representatives of β-CoV have caused serious epidemics in humans, such as the outbreaks of SARS-CoV, MERS-CoV, and COVID-19 caused by SARS-CoV-2. Although the clinical manifestations of CoVs can range from mild cold-like symptoms to severe respiratory diseases, they share common features in their structure, modes of transmission, and natural reservoirs. Identifying natural reservoirs, as well as establishing intermediate hosts, is crucial for understanding the mechanisms of interspecies transmission of CoVs. These processes are often mediated by molecular interactions between viral spike (S) proteins and cellular receptors of different species, which contribute to zoonotic outbreaks. Thus, the interaction of various species and the study of these processes of viral spread, cross-species transmission, and pathogen evolution play a key role in ensuring global biological safety. Therefore, we conducted this review to summarize the data from existing studies focused on the taxonomy of CoVs, their main types, natural reservoirs, intermediate hosts, pathways of interspecies transmission, and the significance of the One Health concept as an interdisciplinary approach to monitoring, prevention and control of CoV infections at the intersection of human, animal, and environmental health. We examined databases such as PubMed, Science Direct, Web of Science, and Google Scholar to identify relevant scientific articles in English available for such a review. The aim of this work is to study the taxonomy and classification of coronaviruses, as well as to identify their natural reservoirs, intermediate hosts, and applicable control measures. A review of human and animal coronaviruses has revealed their evolutionary diversity, their main natural reservoirs, their intermediate hosts, and their interactions with cellular receptors. This information allows for a better understanding of the mechanisms by which the viruses are transmitted from animals to humans. The concept of One Health demonstrated the interconnections between human, animal and environmental factors.

Background/Objectives: Salmonella enterica is a major cause of foodborne infection globally, with poultry acting as an important reservoir. However, data from Central Asia remain limited. This study provides preliminary phenotypic and genomic characterization of S. enterica isolates recovered from poultry farms in southern Kazakhstan, focusing on antimicrobial resistance (AMR), serotypes/sequence types and phylogenetic relationships. Methods: In October 2024, 335 poultry and environmental samples were collected from three regions of southern Kazakhstan using a cross-sectional, detection-focused sampling strategy. Isolation of Salmonella enterica followed enrichment and selective culturing, with confirmation by biochemical assays, slide agglutination serology and real-time PCR. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method and interpreted according to CLSI veterinary breakpoints (VET01/VET08) and CLSI M100 where veterinary criteria were unavailable. Whole-genome sequencing (Illumina) was used for in silico serotyping, MLST, AMR gene detection, plasmid replicon typing and SNP-based phylogenetic reconstruction. Results: Nine S. enterica isolates were confirmed (overall yield 2.7%; 9/335), comprising S. Enteritidis (ST11; n = 4), S. Infantis (ST32; n = 3) and ST68 (n = 2; Choleraesuis/Paratyphi C lineage). All isolates were resistant to ciprofloxacin, and most displayed resistance to ampicillin, gentamicin and trimethoprim-sulfamethoxazole. Plasmid-associated AMR determinants, including blaTEM-116, tet(A), sul1 and dfrA14, were frequently identified on IncF-type replicons. Phylogenetic analysis revealed that the isolates clustered with previously described Eurasian poultry-associated lineages. Conclusions: In this small, exploratory sample from poultry farms in southern Kazakhstan, all recovered S. enterica isolates were multidrug-resistant, with universal fluoroquinolone resistance and frequent plasmid-borne AMR genes. These preliminary findings provide baseline genomic evidence and highlight the need for broader, harmonized AMR surveillance in the regional poultry sector.

This study continues earlier work aimed at identifying potential natural reservoirs of camelpox virus (CMLV) during interepizootic periods. In 2023–2024, field expeditions in western Kazakhstan led to the collection and analysis of biological samples from camels, rodents and hematophagous insects. Despite the absence of clinical symptoms, PCR-positive results were obtained from camel blood samples. These samples underwent molecular genetic analysis, including viral DNA detection and whole-genome sequencing. Using next-generation sequencing, the complete genome of the Camelpox virus/Beineu/2023 isolate (202.273 bp) was obtained and deposited in the NCBI database (accession number PV920573.1). The isolate showed >98% genetic similarity to the previously described Kazakhstan strain M-96, indicating long-term local circulation of a genetically stable variant. Phylogenetic analysis confirmed the isolate’s evolutionary conservatism and close relationship with other CMLV strains. The findings suggest that camels serve as a natural reservoir, enabling viral persistence and potential reactivation under stress-related conditions. The observed geographic clustering underscores the need for region-specific molecular surveillance to ensure timely detection of new variants and prevent cross-border spread.

Hyalomma ticks are known for their ability to transmit a wide range of pathogens, posing a significant threat to both human and animal health. The viral communities associated with Hyalomma asiaticum ticks in Kazakhstan remain largely unexplored. Using high-throughput sequencing on the Ion Torrent platform, nine RNA viruses belonging to seven families were identified. These viruses were associated with H. asiaticum ticks collected in 2024 in southern Kazakhstan. The detected viruses—including Bole tick virus 1 (Phenuiviridae), Bole tick virus 3 (Chuviridae), Bole tick virus 4 (Flaviviridae), Hubei toti-like virus 24 (Totiviridae), Kashgar totiv tick virus 1 (Totiviridae), Lonestar tick totivirus (Totiviridae), Qingyuan parti tick virus 1 (Partitiviridae), and Taishun tick virus (Rhabdoviridae)—had previously been reported only in China. This study provides the first documented evidence of the presence of RNA viruses previously unreported in Kazakhstan within H. asiaticum tick populations. A newly isolated Kazakhstan strain of Wad Medani virus (Sedoreoviridae), identified from H. asiaticum, shares genetic similarities with Russian strains, suggesting a common epidemiological landscape across Central Eurasia. The detection of novel RNA viruses in Kazakhstan highlights the need for ongoing surveillance, as their impact on human and animal health remains insufficiently understood.

This study continues earlier work aimed at identifying potential natural reservoirs of camelpox virus (CMLV) during interepizootic periods. In 2023-2024, field expeditions in western Kazakhstan led to the collection and analysis of biological samples from camels, rodents and hematophagous insects. Despite the absence of clinical symptoms, PCR-positive results were obtained from camel blood samples. These samples underwent molecular genetic analysis, including viral DNA detection and whole-genome sequenc-ing. Using next-generation sequencing, the complete genome of the Camelpox vi-rus/Beineu/2023 isolate (202.273 bp) was obtained and deposited in the NCBI database (accession number PV920573.1). The isolate showed >98% genetic similarity to the previ-ously described Kazakhstan strain M-96, indicating long-term local circulation of a genet-ically stable variant. Phylogenetic analysis confirmed the isolate’s evolutionary conserva-tism and close relationship with other CMLV strains. The findings suggest that camels serve as a natural reservoir, enabling viral persistence and potential reactivation under stress-related conditions. The observed geographic clustering underscores the need for re-gion-specific molecular surveillance to ensure timely detection of new variants and pre-vent cross-border spread.

Background/Objectives: Despite the availability of Newcastle disease (ND) vaccines, outbreaks have continued to occur for more than six decades, with significant economic consequences for the global poultry industry. The variability of the Newcastle disease virus requires constant monitoring, detection of new cases, and studies of the origin of the pathogen. The aim of this study was to develop an inactivated ND vaccine using a topical strain with different adjuvants and to compare them for stability, harmlessness, immunogenicity, and efficacy. Methods: A phylogenetic study of the F-gene of the ND strain isolated in Kazakhstan was conducted. The strain, which was selected to create a vaccine for the prevention of the disease, was revealed to belong to genotype VII class II and uploaded to GenBank (NCBI). Two different adjuvants, Montanide ISA 70 VG and Montanide ISA 78 VG, were used to create the vaccine. Birds were vaccinated intramuscularly. Results: Evaluations of antibody titers in the vaccinated groups during the experiment showed that the vaccines induced adequate levels of antibodies to provide protection against the virulent virus. High antibody titers were observed in the hemagglutination inhibition assay (HAI) in the vaccinated groups as early as 14 days post-vaccination in 100% of birds. The average antibody titer in both vaccinated groups exceeded 7 log2, sufficient to prevent clinical signs. None of the vaccinated birds exhibited clinical signs following control infection, whereas unvaccinated birds developed clinical manifestations within three days post-infection, leading to 100% mortality. Conclusions: The vaccine developed using the epizootic topical strain is stable, harmless, immunogenic, and effective when challenged with a virulent ND virus strain at a dose of 105 EID_50/mL.

Prompt determination of the etiological agent is important in an outbreak of pathogens with pandemic potential, particularly for dangerous infectious diseases. Molecular genetic methods allow for arriving at an accurate diagnosis, employing timely preventive measures, and controlling the spread of the disease-causing agent. In this study, whole-genome sequencing of three SARS-CoV-2 strains was performed using the Sanger method, which provides high accuracy in determining nucleotide sequences and avoids errors associated with multiple DNA amplification. Complete nucleotide sequences of samples, KAZ/Britain/2021, KAZ/B1.1/2021, and KAZ/Delta020/2021 were obtained, with sizes of 29.751 bp, 29.815 bp, and 29.840 bp, respectively. According to the COVID-19 Genome Annotator, 127 mutations were detected in the studied samples compared to the reference strain. The strain KAZ/Britain/2021 contained 3 deletions, 7 synonymous mutations, and 27 non-synonymous mutations, the second strain KAZ/B1.1/2021 contained 1 deletion, 5 synonymous mutations, and 31 non-synonymous mutations, and the third strain KAZ/Delta020/2021 contained 1 deletion, 5 synonymous mutations, and 37 non-synonymous mutations, respectively. The variations C241T, F106F, P314L, and D614G found in the 5′ UTR, ORF1ab, and S regions were common to all three studied samples, respectively. According to PROVEAN data, the loss-of-function mutations identified in strains KAZ/Britain/2021, KAZ/B1.1/2021, and KAZ/Delta020/2021 include 5 mutations (P218L, T716I, W149L, R52I, and Y73C), 2 mutations (S813I and Q992H), and 8 mutations (P77L, L452R, I82T, P45L, V82A, F120L, F120L, and R203M), respectively. Phylogenetic analysis showed that the strains studied (KAZ/Britain/2021, KAZ/B1.1/2021, and KAZ/Delta020/2021) belong to different SARS-CoV-2 lineages, which are closely related to samples from Germany (OU141323.1 and OU365922.1), Mexico (OK432605.1), and again Germany (OV375251.1 and OU375174.1), respectively. The nucleotide sequences of the studied SARS-CoV-2 virus strains were registered in the Genbank database with the accession numbers: ON692539.1, OP684305, and OQ561548.1.