Introduction. Epizootic hemorrhagic disease (EHD) is a vector-borne, infectious, non-contagious disease affecting wild and domestic ruminants, characterized by congestive and hemorrhagic manifestations. The causative agent is a virus of the genus Orbivirus family Sedoreoviridae, which is transmitted between susceptible animals through the bites of Culicoides midges. Over the past 20 years, epizootic hemorrhagic disease virus (EHDV) has spread to new regions. Since 2022, large scale outbreaks among cattle have been reported in Southern Europe, posing a serious threat to the livestock industry.

Objective. To summarize and analyze current published data on the global situation regarding EHD.

Materials and methods. Analytical research methods were employed using the following databases: PubMed, Willey Online Library, MDPI, Google Scholar, eLibrary, and CyberLeninka.

Results. A brief description of the disease’s causative agent is provided. To date, seven serotypes of EHDV have been identified worldwide, with a novel serotype 10 recently reported. A global geographical spread of EHDV across all continents is observed, with regional variations in serotype distribution. Serotypes 1, 2, 6, 7, 8, and 10 exhibit increased pathogenicity, causing EHD outbreaks in deer and cattle. This review briefly discusses the factors contributing to the spread of EHDV to new territories. It also describes clinical signs of EHD in susceptible animals, outlines key prevention and control measures to reduce the risk of new outbreaks, and identifies current research gaps.

Conclusion. The ability of EHDV to undergo recombination, the emergence of highly virulent strains, and the progressive expansion of vector ranges may lead to large-scale outbreaks with significant economic losses in the livestock sector, including European and Asian countries. In current conditions, it is necessary to enhance entomological and virological surveillance for the early detection and control of EHDV spread among ruminants.

Introduction. Innate immunity is controlled by a complex network of activating and regulatory mechanisms. One of the most important factors in this regulation is the acute phase response in the liver. Following infection or tissue damage, protein synthesis patterns in the liver change dramatically within a few hours: expression of the so-called positive and negative acute phase proteins (APPs) increases. The most common application of acute phase proteins is diagnostics and assessment of tissue damage in humans, inter alia in inflammatory processes. APPs are important for diagnosing inflammation because their concentrations rapidly increase and fluctuate significantly during various pathological processes. However, most APPs lack specificity with respect to the primary cause of inflammation. In veterinary medicine, this factor accounts for their rare use as a primary diagnostic test for a specific disease.

Objective. The aim of this review was to summarize data on the APPs most widely used in clinical practice and to examine the results of existing veterinary studies investigating APPs in the diagnosis of inflammatory diseases in the mammary gland of cows.

Materials and methods. The data were summarized for this literature review using the elements of the PRISMA statement. The AMSTAR method was used to assess the methodological quality of systematic reviews and meta-analyses. The search and selection of original publications was conducted using Scopus, Web of Science, PubMed, MedLine, ScienceDirect, and eLibrary databases.

Results. This article examines the most studied inflammatory APPs and describes their main effects. It has been established that approximately 40 different plasma proteins classified as APPs have been studied to date. In veterinary medicine, the most important APPs used to diagnose various diseases associated with inflammation include C-reactive protein, serum amyloid A, haptoglobin, alpha-1-acid glycoprotein, and lipopolysaccharide-binding protein. Data on APP studies in cows with mammary gland inflammation are presented.

Conclusion. The meta-analysis identified the most significant APPs that can serve as diagnostic markers for mastitis in cows. These include serum amyloid A, haptoglobin, alpha-1-acid glycoprotein, and lipopolysaccharide-binding protein.

Pythiosis is a chronic granulomatous disease affecting various animal species, most commonly equines. It occurs in tropical, subtropical, or temperate climates and is associated with waterlogged areas, such as swamps and ponds. The causative microorganism parasitizes aquatic plants and produces motile zoospores capable of infecting hosts through cutaneous lesions. Pathogenesis is associated with a predominant Th2-type immune response, characterized by the production of interleukins such as IL-4, IL-5, and IL-13, as well as intense eosinophilia and granulomatous inflammation, which contributes to the agent’s persistence in tissues. Clinically, the disease is characterized by the formation of eosinophilic granulomas containing “kunkers”, necrotic masses composed of hyphae, collagen, and inflammatory cells. Various therapeutic approaches have been employed, including the use of antifungals, surgery, and immunotherapy. Surgical removal combined with immunotherapy is considered the most effective strategy, although treatment poses challenges due to the agent’s unique characteristics; unlike true fungi, its cell wall contains cellulose and β-glucans. This study aims to analyze the biological and infectious aspects of Pythium insidiosum and to characterize the immunopathogenesis of equine pythiosis, focusing on the interaction between the etiological agent and the host immune response.

Introduction. Leptospirosis is an infectious disease hazardous to both humans and animals. Dogs serve as a key link in transmitting the infection to humans. Within the Russian Federation, the Canicola and Icterohaemorrhagiae serogroups are of primary relevance for dogs as the most virulent ones, although infection with other Leptospira spp. serogroups remains possible. The severity of the disease is determined by the pathogenicity factors of leptospires. Due to the zoonotic nature of leptospirosis, canine vaccination is a vital element of sanitary and epidemiological freedom. Regular immunization reduces the risk of human infection and prevents outbreaks. When selecting vaccines, the limited cross-protection between serogroups should be considered, with polyvalent products being preferred. However, existing vaccines do not provide reliable protection due to outdated serogroup compositions. The persistence of the causative agent within the animal host and its shedding into the environment diminish the effectiveness of prevention. A comprehensive approach is required to prevent canine infection and subsequent causative agent transmission to humans.

Objective. To update and systemize data on canine leptospirosis caused by Leptospira interrogans.

Materials and methods. Scientific publications by foreign and domestic authors available in bibliographic databases such as eLibrary, CyberLeninka, PubMed, Science Direct, Google Scholar, and others served as the material for this analytical study.

Results. This analytical review presents up-to-date data on the epizootic and epidemiological situation regarding leptospirosis in the Russian Federation. It examines the properties of the causative agent, presents the classification of leptospires, and describes the clinical and post-mortem lesions of the disease. Furthermore, the review characterizes modern methods of laboratory diagnosis, treatment, and prevention of canine leptospirosis currently applied in veterinary practice, and outlines existing challenges.

Conclusion. Leptospirosis is widespread in dogs. Leptospires are capable of adapting and persisting in the host organism, causing a chronic course of the disease, which poses a threat to human and animal health. The complexity of pathogenesis, the diversity of serotypes and intracellular persistence complicate the eradication of the causative agent. Current diagnostic and treatment methods require improvement. Research is needed to develop effective prevention and therapy protocols, including new approaches to specific prevention in dogs. Thus, leptospirosis remains a pressing issue in veterinary medicine requiring a comprehensive approach.

Introduction. The Novosibirsk Oblast is classified as a rabies-endemic region within the Siberian Federal District of the Russian Federation, ranking first in the number of reported cases among all constituent territories of the district. However, there is a notable lack of research on the genetic properties of the rabies virus field isolates.

Objective. This study seeks to assess how rabies outbreaks in the rabies endemic Novosibirsk Oblast are connected with those in the neighbouring regions, by analyzing genetic diversity of rabies virus variants and their spatial distribution.

Materials and methods. Two overlapping genome fragments containing full-size nucleoprotein (N) gene of rabies virus were Sanger-sequenced following purification, using a previously established procedure. Phylogenetic analysis was performed using a Bayesian approach as implemented in the Bayesian Evolutionary Analysis Sampling Trees (BEAST Х) software package.

Results. The number of registered animal rabies cases after 2012 declined markedly and has not exceeded 60 cases per year. All the studied isolates belong to genetic group C. The isolates are classified into two genetic clusters – C2c (35 isolates) and C2b (18 isolates). One of the rabies virus isolates was recovered in mouse neuroblastoma cell culture. All group C clusters found in the Novosibirsk Oblast have previously been reported in Kazakhstan as well. The most stable connections are observed within the East Kazakhstan (Сlusters C2c, C1b) and North Kazakhstan (Сlusters C2c, C2b) Oblasts. Results of the phylogenetic analysis are consistent with earlier descriptions of “fox” rabies and with the findings of epizootiological monitoring in adjacent territories of Western Siberia and Kazakhstan.

Conclusion. At present, two independently derived virus clusters – C2b and C2c – are circulating in the Novosibirsk Oblast.

Introduction. Although rabies incidence in Russia has decreased over the past ten years, it still remains a highly relevant disease. Polymerase chain reaction (PCR) in its various modifications is one of the tools for detecting and characterizing rabies virus in pathological samples. To ensure reliable diagnosis, the current data on genetic properties of the isolates circulating in particular area should be considered when developing PCR.

Objective. Providing a theoretical foundation and optimizing the test system based on combined reverse transcription polymerase chain reaction (C-RT-PCR) for the detection of a rabies virus genome fragment using endogenous internal control.

Materials and methods. Rabies virus vaccine strain “RV-97” and laboratory fixed rabies virus strain “CVS”, brain samples from animals of various species, both rabies virus positive and negative, were used in the work. Oligonucleotide design and in silico specificity testing were performed using Primer Blast online tool. Syntol reagents (Russia) were used for C-RT-PCR.

Results. As a result of the analysis of 193 N-gene sequences of rabies virus isolates circulating in Russia and neighboring countries, six primers and two TaqMan probes were designed. Two primers and a probe, optimal for the development of the test system, were experimentally identified. During a series of experiments, C-RT-PCR parameters such as oligonucleotide and magnesium ion concentrations, as well as annealing temperature were optimized. To control the reaction conditions in each tube, an oligonucleotide system was developed for the amplification and detection of the mammalian beta-actin gene region. The possibility of simultaneous application of two PCR systems in one test tube has been experimentally demonstrated. Analysis of 193 N-gene sequences of various rabies virus isolates showed that the developed oligonucleotides can theoretically ensure detection of the vast majority of the viruses circulating in the Russian Federation and neighboring countries.

Conclusion. The main components and reaction conditions of the test system for detecting the rabies virus genome by C-RT-PCR using mammalian beta-actin gene-based endogenous internal control have been developed and optimized.

Introduction. Canine dirofilariasis is a widespread vector-borne helminthiasis in which the immune response to the parasite and its endosymbiont Wolbachia plays a key role in pathogenesis; however, the mechanisms underlying the development of autoimmune complications remain insufficiently studied.

Objective. To investigate the cytokine profile, Th1/Th2 balance, and their relationship with eosinophilia, hyperproduction of IgE, and the formation of circulating immune complexes (CICs) in dogs with varying severity of dirofilariasis.

Materials and methods. The study included 113 dogs: 26 clinically healthy animals (control group) and 87 dogs diagnosed with dirofilariasis, divided into four groups (I–IV) according to disease severity. Concentrations of TNF-α, IL-1α, IL-4, IL-6, IL-8, IFN-γ, and total IgE were determined by enzyme-linked immunosorbent assay (ELISA). Eosinophil counts were performed as part of the complete blood count. Statistical analysis was carried out using the Kruskal – Wallis and Mann – Whitney U tests.

Results. In diseased dogs, a pronounced cytokine storm was observed: IL-4 levels in group IV exceeded the control by 4.7-fold (p < 0.001), IL-6 by 4.3-fold, IL-8 by 7.5-fold, and TNF-α by 3.3-fold. The IL-4/IFN-γ ratio increased from 3.01 in the control group to 3.17–3.58 in groups III–IV, indicating a predominant Th2-type immune response. The relative eosinophil count increased in groups I–II [up to (5.54–6.04)%, p < 0.01] and decreased in groups IV [up to (2.44 ± 0.54)%, p < 0.05]. Total IgE levels progressively rose from (15.20 ± 1.80) U/mL in the control group to (92.50 ± 10.60) U/mL in group IV. Total CICs in group IV reached (57.31 ± 2.05) U/mL [control: (28.60 ± 0.87) U/mL, p < 0.001].  Correlation analysis revealed a positive association between IL-4 and IgE (r = 0.78, p < 0.01) as well as between IL-4 and total CICs (r = 0.71, p < 0.01).

Conclusion. The predominance of the Th2-type immune response, combined with a cytokine storm, triggers a cascade of reactions, including IgE hyperproduction and eosinophilia, and promotes massive formation of immune complexes. This creates a pathogenetic basis for the development of autoimmune pathology in canine dirofilariasis.

Introduction. The rising prevalence of antibiotic resistance among pathogenic clostridia in the agro-industrial sector of the Ural Federal District highlights the need for this study. Emerging resistant strains compromise therapeutic outcomes, exacerbate economic losses attributable to infectious diseases, and pose a tangible threat of interspecies antimicrobial resistance gene transfer. These factors collectively necessitate the development of state-of-the-art molecular surveillance tools as a part of national antimicrobial resistance mitigation strategies.

Objective. The study was aimed at the development and testing of the PCR test systems for detection of antibiotic resistance genes (tetM/B, ermB/Q, bcrA/B/D/R) in Clostridium perfringens and Clostridium difficile.

Materials and methods. During the study 472 biological samples (animal feces, wound discharge, feed, environmental objects) collected on 32 dairy holdings located in the region in 2023–2024 were tested. The recovered isolates’ species identity was confirmed by MALDI-ToF mass spectrometry, and the phenotypic antibiotic resistance was determined by disc diffusion method in accordance with EUCAST standards. Bank of DNAs extracted with PCR from submitted biological samples and Clostridium isolates, strains of various species of spore-forming anaerobes kept at the Microorganism Strain Collection was created.

Results. Effective PCR test-kit for the detection of antibiotic resistance genes in Clostridia spp. was successfully developed and validated. Screening of 123 samples containing DNA of the target pathogens revealed a high prevalence of resistance genes: ermB gene (95.1%) was most common in Clostridium difficile, ermB (90.0%) and ermQ (67.1%) genes were predominant in Clostridium perfringens. The tetМ gene was detected in 52.4 and 60.0% of samples, respectively, while the bcrA/B/D/R genes were detected in 27.1–39.8% of isolates. Phenotypic studies confirmed the emergence of multidrug resistance in Clostridia spp.

Conclusion. The developed test kit has proven to be a reliable and robust tool for molecular antimicrobial resistance surveillance. The data obtained indicate a widespread circulation of Clostridium spp. harboring genetic determinants for resistance to clinically significant antibiotics.

Introduction. Ulcerative diseases of the bovine hoof and adjacent soft tissues – including digital dermatitis – are widespread globally. Mechanical trauma predisposes these tissues to microbial invasion, triggering purulent-ulcerative lesions that frequently progress to tissue necrosis. These conditions are typically polymicrobial in nature. However, the associated microorganisms can be classified into three pathogenetic groups: primary, complicating and secondary pathogens. Anaerobic bacteria, particularly Fusobacterium spp. and Clostridium spp., play a significant role in the development of infectious hoof diseases in cattle.

Objective. Determination of the etiological cause of ulcerative hoof diseases in cattle.

Materials and methods. Microbiological methods were used for the study. Animals with ulcerative hoof lesions were divided into two groups: animals receiving treatment and animals without treatment (newly diagnosed cases).

Results. Detected contaminants associated with ulcerative hoof lesions in cattle included: Fusobacterium spp., Clostridium spp., Klebsiella pneumonia and Enterococcus faecalis. Fusobacterium spp. played a major role in the disease progression. Clostridium spp. were isolated from deep lesions, creating anaerobic environment required for their development.

Conclusion. The predominant microorganisms isolated from ulcerative hoof lesions in cattle were Fusobacterium spp., detected in 100% of samples, followed by Klebsiella pneumoniae (90%) and Clostridium spp. (80%).

Introduction. In modern microbiology, the collection and maintenance of microorganism collections in working order is one of the most important areas of practical activity in a microbiological laboratory.

Objective. To carry out reactivation of non-viable mycobacterial cultures isolated from animal biomaterial and environmental samples in liquid and solid nutrient media with a growth supplement, followed by bacteriological, molecular biological and molecular genetic typing of the recovered pathogens.

Materials and methods. The reactivation process involved inoculating the cultures in Middlebrook 7H9 liquid medium and Löwenstein – Jensen solid medium using OADC growth supplement. Subsequent mycobacteria identification was performed using time-of-flight mass spectrometry and microarray hybridization with the MYCO-BIOCHIP (Russia) test system.

Results. For the in vitro experiment, 75 mycobacterial culture samples in a non-culturable state, obtained from processed animal biomaterial and environmental specimens, were selected. A total of 46 (61.3%) cultures were reactivated, among which Mycobacterium tuberculosis (4.3%) and non-tuberculous mycobacteria of the following species were identified: slow-growing pathogenic Mycobacterium avium (65.2%) and Mycobacterium intracellulare (2.2%); slow-growing non pathogenic Mycobacterium nonchromogenicum (15.2%) and Mycobacterium monacense (2.2%); fast-growing pathogenic Mycobacterium fortuitum (4.3%) and Mycobacterium abscessus (2.2%), fast-growing opportunistic Mycobacterium neoaurum (2.2%) and Mycobacterium kyogaense (2.2%). Among the reactivated cultures, the leading role belonged to group III non-tuberculous mycobacteria according to Runyon’s classification: Mycobacterium avium, Mycobacterium nonchromogenicum, Mycobacterium intracellulare.

Conclusion. Under microbiological laboratory conditions, 46 out of 75 field isolates of mycobacteria were successfully reactivated, yielding viable cultures and demonstrating the effectiveness of the reactivation method used. The key characteristics of the obtained cultures and the species diversity of the mycobacterial collection were preserved. The results of this study can be used to optimize laboratory microbiological diagnostics of tuberculosis.

Introduction. Bats are recognized as natural reservoirs for a wide range of viruses and are therefore traditionally viewed as a potential biological hazard. This perception, however, conflicts with the growing operation of bat rehabilitation centers, where the concentration of animals – if not accompanied by rigorous virological monitoring – may inadvertently facilitate pathogen transmission. A viable resolution lies in integrating preliminary virological screening into standard intake protocols. Early identification of viral carriers and their timely quarantine would not only protect both animal cohorts and center personnel but also generate valuable surveillance data to support early warning systems for emerging viral genetic variants.

Objective. To validate a combined methodological approach for reconstructing full-genome sequences of bat-derived RNA viruses under conditions of low viral load and fragmented RNA templates. The proposed strategy involves the sequential application and adaptation of amplicon-based sequencing and random priming (SMART-9N) techniques.

Materials and methods. Fecal samples were collected from bats housed at a rehabilitation center in Rostov-on-Don between 2022 and 2023. The manuscript details the complete workflow, from nucleic acid extraction through to bioinformatic data processing and analysis. Three RNA template enrichment strategies based on reverse transcription and PCR are also described and compared.

Results. A primer panel was developed specifically for the detection of bat alphacoronaviruses. Metagenomic analysis further revealed the presence of viral RNA corresponding to Bat bastrovirus (family Astroviridae), for which confirmatory diagnostic primers were subsequently designed. Notably, the complete genomic sequence of Loanvirus brunaense (family Hantaviridae) was obtained, along with 95% of the nucleotide sequence of an Alphacoronavirus (family Coronaviridae).

Conclusion. Viral genetic sequence data are indispensable across diverse fields, including fundamental science, clinical medicine, veterinary practice, and public health. The findings of this study provide a practical foundation for the development of rapid diagnostic test kits aimed at detecting bat-associated viruses.