The paper highlights the current knowledge on infection biology, epidemiology and evolution of monkeypox virus (MPXV), cowpox virus (CPXV), buffalopox virus (CPXV), camelpox virus (CMLPV), as well as addresses some factors that modulate dynamics of orthopoxvirus transmission, manifestation of orthopoxvirus infections and their preservation in nature. Despite the elimination of the historically infamous smallpox, orthopoxviruses remain a serious veterinary and health problem. Their role is currently increasing while the number of persons not immune to smallpox grows. Along with this, there is a genetic transformation of pathogens. In this regard, the risks of human infection with orthopoxviruses of zoonotic nature are increasing. The problem of monkeypox, cowpox, buffalopox and camelpox and the respective agents included in the genus of zoonotic orthopox viruses presents the greatest interest. Along with the increased number of human monkeypox cases in 2020–2022, a retrospective analysis of the last 20 years shows that the activity of monkeypox outbreaks in the XXI century intensified in Central African countries. Cowpox outbreaks in Europe and camelpox outbreaks in Southwestern and Central Asia have also become more active. In 2011, in India, the camelpox virus overcame the interspecies barrier and caused a clinical pox-like disease in humans. Scientists are alarmed by these facts as the camelpox virus genomeis 99% homologous to the genome of the small poxvirus. This requires strengthening the epizootological and epidemiological monitoring of orthopoxvirus zoonotic pathogens.

The following review considers modern scientific data on respiratory diseases in young cattle. The problem of respiratory diseases in calves does not lose its relevance, since these pathologies rank second in frequency after diseases of the digestive system. In order to compile the data, the works of domestic and foreign researchers and collectives available in the collections of scientific conferences, seminars, symposiums, as well as in peer-reviewed periodicals, materials of dissertations and abstracts were reviewed. The group of pathologies under consideration is sufficiently diverse and can be caused by high animal density in the premises, overheating, hypothermia, unbalanced feeding, micronutrient deficiency, decreased body resistance, unfavorable epidemic situation and many other factors. However, out of the major calf diseases, particular mention should be made of pneumonia, which is most often caused by viruses. In this case agents can induce bacterial infection which aggravates and complicates the course of viral diseases. Microorganisms, such as Salmonella, Pasteurella and others, contribute to secondary infection and cause mixed forms of pneumonia. Bronchopneumonia is another disease covered in the article. It is a respiratory pathology characterized by inflammation of both the bronchi and lungs. As a rule, such disease types are most common in industrial animal husbandry, they are widespread and cause significant economic damage to the dairy and beef cattle breeding industries. The article pays great attention to these pathologies, justifies the importance of comprehensive preventive measures and timely diagnosis for livestock industries. To reduce the incidence of respiratory diseases in young cattle, it is necessary to strictly follow technological and hygienic standards for animal keeping and feeding. The use of combined medicines and preparations containing microelements increases treatment effectiveness.

Reindeer invasive diseases causes ignificant damage to reindeer farms due to reduction in animal productivity and deterioration in quality of reindeer products. Helminthiases take a special place among them. Knowledge of the epizootic situation will contribute to the successful organization of a system of therapeutic and preventive measures to protect the domestic reindeer stock from helminthiases. The article presents assessment results for the invasive disease epizootic situation in reindeer farms in the Murmansk Oblast in 2018–2021. The research was carried out in two large reindeer farms – APC “Tundra” and APC HFESEN “Olenevod” during the planned slaughter of reindeer. A totalof 4,048 deer carcasses of all ages were examined and 199 samples of faeces were tested. A retrospective analysis of the veterinary service’s data showed that, among helminthiases, mainly cysticercosis is recorded in reindeer herds of the Murmansk Oblast. The prevalence of cestodes infection variesfrom 0.16 to 0.83% depending on the year, however the extensiveness of cysticercosis invasion of reindeer is decreasing. The prevalence of oedemagenosis varied in different age and sex groups from 25 to 100%. It was found that reindeer of all ages were infested with paramphistomiasis (12.50–15.15%), setariasis (5.36–6.06%), nematodiasis (3.0–6.0%), dictyocaulosis (3.03–3.57%), protostrongylosis (3,0%) and, to the least extent, echinococcosis (0.04%). Helminths of the genus Taenia, class Cestoda, that cause cysticercosis, mainly infest young animals – extensiveness of invasion (EI) is 0.50–0.81%. Thus, oedemagenosis and paramphistomiasis prevail in the structure of helminth infections; they are recorded in all reindeer herds. It was established that invasive diseases occur in the form of mixed invasions. Mixed invasions most often occur in the following associations: oedemagenosis + protostrongylosis, oedemagenosis + paramphistomiasis + setariasis, oedemagenosis + paramphistomiasis + cysticercosis (finnosis), oedemagenosis + dictyocaulosis + protostrongylosis.

Results of epizootological analysis of data on bovine leucosis (BL) incidence in the Republic of Dagestan in 2021 are reported. Bovine blood was diagnostically tested for leukosis in 32 veterinary laboratories and diagnostic offices including SBI RD Republican Veterinary Laboratory. 720,489 sera were serologically tested and 7,188 (1.0%) samples were serologically positive for bovine leukaemia virus (BLV). Among the infected animals, 527 ones were subjected to haematologic testing. Persistent leukocytosis was reported in 153 (29.03%) blood samples of haematologically tested BL diseased cattle. Statistical analysis of BLV prevalence in the republic was performed for 41 Raions and 8 municipalities. High percentage of BLV infection in the animal population was reported in fourteen Raions: Kumtorkalinsky (5.8%), Gunibsky (5.3%), Tarumovsky (3.3%), Karabudakhentsky (2.9%), Akhvakhsky (2.0%), Kizlyarsky (1.8%), Charodinsky (1.7%), Kazbekovsky (1.6%), Babayurtovsky (1.5%), Tlyaratinsky (1.1%), Dakhadayevsky (1.04%), Sergokalinsky (1.02%), Novolaksky (1.0%), Shamilsky (1.0%), and in four municipalities: Makhachkala (2.0%), Izberbash (1.14%), Khasavyurt (1,1%) and Yuzhno-Sukhokumsk (1.0%). In 21 Raions and two municipalities, BLV seropositivity was below 1.0%. No BLV infected animals were detected in the Agulsky, Akhtynsky, Dokuzparinsky, Magaramkentsky, Khivsky, Suleiman-Stalsky Raions and in Derbent and Dagestanskiye Ogni municipalities. Studies of BLV prevalence in 2015–2021 demonstrated that the highest level of the animal infection was reported in 2015 (13.9%) and the lowest – in 2021 (1.0%). However, the number of animals serologically tested in 2021 exceeded the number of animals tested over the whole study period. Therefore, the Republic of Dagestan remains BL infected region.

Lack of statistical data and inconsistences in science and practice make it impossible to give at least approximate tuberculosis prevalence rates in the Republic of Dagestan. Every year the number of tuberculin reacting animals is increasing. For example out of 2,944 tested heifers of breeding age in 2014–2019, up to 30% of animals had positive reactions in tests. During this period out of 1,166 emergency slaughtered animals, tuberculosis was confirmed in 326 animals (28%). Bacteriological tests revealed 291 mycobacterium cultures, 107 out of them were Mycobacterium bovis, the other 184 cultures were identified as atypical ones. Based on the species differentiation of 58 cultures, 22 Group II cultures (according to Runyon classification) were isolated; 18 out of them belonged to Mycobacterium gordonae, 2 to Mycobacterium flavescens, and species of two cultures could not be identified. Four cultures of Group III were species of Mycobacterium intracellulare. Out of 32 cultures of Group IV, two belonged to Mycobacterium smegmatis, seven to Mycobacterium fortuitum and one to Mycobacterium phlei, 22 cultures were not identified. To elucidate the role of milk in tuberculosis epidemiology 82 samples of milk from reactors from two farms were tested. In the farm, where reactors were awaiting their removal for a long time, mycobacteria were detected in 20% of milk samples, whereas in the recently infected farm the detection rate was 4%, which suggests that long awaiting periods present high risks. Microscopic, conventional phenotypic and targeted biochemical tests indicate that pseudo-allergic reactions, revealed by tests, result from the atypical mycobacteria of the mentioned groups and species, which present in the animal organism, and seem to be responsible for the tuberculin sensibilization. Timely and comprehensive diagnostic and animal health measures will improve the situation.

The paper presents trends in the epizootic situation on classical swine fever (CSF) in the Russian Federation, for 2007–2021. Most likely, a drop in the number of CSF outbreaks throughout the country results from two factors: a geographical shift of the disease outbreaks from the European part of Russia to the eastern regions bordering on China (into the wild boar population), as documented between 2015 and 2021, and a large-scale vaccination of domestic pigs practiced in the recent years. The introduction and spread of CSF in the Russian Federation are, most likely, associated with the internal risk factors (i.e. quality of anti-epizootic measures, mainly vaccination) and with the territories, where the virus circulates in wild boars. Expansion of vaccination coverage since 2011 is one of the factors contributing to a decrease in the number of clinical CSF cases registered in domestic pigs of the Russian Federation. The infection spread in domestic pigs is still on a downward trend. For purposes of analysis, current trends of CSF spread in domestic pigs and wild boars in the Russian Federation, as well as the volume of the vaccine used, were visualized in relative numbers (taking into account total number of pigs in the country) used to build a regression model. Currently, vaccination against classical swine fever in the Russian Federation (and its good quality) is an essential prerequisite to contain the infection spread in the country.

During the analyzed period of 2015–2018 number of pigs kept on backyards and in agricultural organizations as well as number of wild boars living in the Crimean lands declined by 25.34% and 26.09%, respectively, due to African swine fever introduction. In 2016–2018, ASF epizootic situation in domestic pigs and wild boars was the most complicated in the Sovetsky, Razdolnensky, Belogorsky Raions and in Sudak municipality, respectively. The unauthorized burials of dead domestic pigs, which could have caused the dangerous disease agent introduction into the wildlife were detected. Number of tests for ASF carried out within both passive and active monitoring increased during the said period: 527 tests were carried out in 2015 and 7,754 tests were carried out in 2018. In 2018, ASF virus was detected with polymerase chain reaction (PCR) in 8 samples of pathological materials from wild boars, that was 0.1% out of total number of the samples tested in the FGBI “ARRIAH” Branch in the Republic of Crimea and FGI RC “Regional State Veterinary Laboratory of the Republic of Crimea”. Large-scale diagnostic tests performed in domestic pigs and wild boars contributed to rapid diagnosis of outbreaks and disease eradication. It should be noted that in case of ASF occurrence in domestic pigs only, the disease could be eradicated with a complex of anti-epizootic measures in initial outbreak areas. Absence of the disease in the Crimean Peninsula during the last years proves the effectiveness of the measures taken for ASF spread prevention.

Bovine leukosis is one of the most common infectious diseases of farm animals, causing significant economic damage due to a decrease in production of livestock products, premature culling and slaughter of cows and servicing bulls. The disease needs special attention and control on behalf of the on-farm veterinarians and zootechnicians. The article briefly describes epizootic situation on bovine leukosis in the Russian Federation in 2004–2020. It also includes a report on the disease situation in “Sibirskaya Niva” LLC (the Irkutsk Oblast) for 2015–2021 and assesses effectiveness of health support and disease prevention measures taken on the farm. The paper gives a brief description of the agricultural establishment: its zoosanitary status as well as zootechnical, veterinary, therapeutic and preventive measures (disinsection, deratization, vaccination). Based on the data obtained, we found the ultimate cause of bovine leukosis on the farm: presumably, these were crossbred animals brought into the farm. In order to eradicate the disease, “Sibirskaya Niva” LLC has developed a plan on health support and disease prevention, which includes veterinary, zootechnical and economic measures. Thus, due to the actions taken from 2015 to 2019, the number of infected cows and heifers reduced by 6.42 and 2.78 times, correspondingly. At the same time, the overall number of infected animals decreased by 9.9%. Task-oriented measures taken by the state veterinary services made it possible to steadily reduce the number of infected animals by 2020. The comprehensive approach embracing the farm peculiarities has proven to be effective to quickly eliminate bovine leukosis, as the above-mentioned agricultural establishment exemplified it.

In vaccine production, it is particularly important to purify the virus-containing suspension in order to remove ballast proteins and fats, which, when present in high concentrations, are responsible for depression or allergic reactions in animals. Polyguanidine and its derivatives have long been used for such purposes. At present, the market offers polyhexamethylene guanidine hydrochloride, a cationic polyelectrolyte with aunique combination ofphysico-chemical and biocidal properties allowing for it to be used in nearly all spheres of economy. Flocculation properties of polysept (polyhexamethylene guanidine hydrochloride) vary from batch to batch, and this has necessitated the development of a test system for determination of the incoming material quality, which has a significant impacton virus antigen concentration during vaccine production. Seven batches of polyhexamethylene guanidine were tested for flocculation properties, changes in FMDV immunogenic component concentration in the virus-containing suspension, osmolality of solutions at different percentage concentrations. Indicators of incoming material suitability for FMD vaccine production were determined. The batches of polysept should be tested for flocculation properties at different concentrations of thepolymer (0.007, 0.0105 and 0.01575%) in dynamics during 24 hours. After this period, the turbidity of solutions should not exceed 30 FNU (formazin turbidity) at concentrations of 0.0105 and 0.01575%. It is also necessary to determine the osmolality of polysept solutions at different percentage concentrations (6, 8, 10, 12, 14%). Osmolality values should be within the following ranges: 260 ± 20 mOsm fora 6% solution; 330 ± 25 mOsm foran 8% solution; 400 ± 25 mOsm fora 10% solution; 460 ± 30 mOsm fora 12% solution; 520 ± 20 mOsm fora 14% solution.

Mycoplasma bovis is considered one of bovine mycoplasmosis pathogens responsible for respiratory diseases, mastitis, arthritis and keratoconjunctivitis. The paper presents results of the study on optimizing the component composition of the culture medium for Mycoplasma bovis “Kaluga 2020” isolate, as well as the study of this pathogen’s growth stages. The color-changing units assay and the culture method combined with colony-forming unit quantification were used for determination of Mycoplasma activity. It was found that when cultured in an optimized nutrient medium based on modified Hayflick broth, the microorganism enters a logarithmic growth phase after first 24 hours ofgrowth, in 72 hours the Mycoplasma culture enters astability phase, and adecline phase is recorded in 84 hours. The effect of percentage content of glucose, fresh yeast extract and horse serum in the nutrient medium on accumulation of Mycoplasma bovis “Kaluga2020” isolate was evaluated using the one-factor-at-a-time approach. It was found that the greatest effect on Mycoplasma accumulation was exerted by such growth factors as fresh yeast extract and horse serum in the nutrient medium (p < 0.05), while changes in the amount of glucose did not stimulate Mycoplasma bovis growth. Based on results of the conducted studies, the appropriate composition was determined and the optimal content of growth factors in the medium for culturing Mycoplasma bovis “Kaluga 2020” isolate was selected: 12.5%of fresh yeast extract and 25% of horse serum. The use of the optimized nutrient medium based on modified Hayflick broth allowed 5-fold increase in accumulation of Mycoplasma biomass (3.98 × 10⁹CFU/ml)compared to the standard medium (0.79 × 10⁹CFU/ml).

Melioidosis is a highly dangerous infectious disease caused by Hazard Group II bacteria Burkholderia pseudomallei, against which specific prevention and treatment tools have not been developed yet. Both humans and animals suffer from the disease. Previously the disease was prevalent in Southeast Asia regions, but currently is reported almost in all continents of the globe. Potential possibility of the agent introduction to the Russian Federation as well as the risk of malevolent use of this agent as a tool of bioterrorism dictates the need for storage of this pathogen in the microorganism collections to study its properties, develop and test diagnostic, detection and identification means. Microorganism Collection Laboratory of the FSBSI “FCTRBS-ARRVI” is responsible for storage and preservation of Burkholderia pseudomallei С-141 reference strain, submitted by Federal State Scientific Institution “Russian Research Anti-Plague Institute “Microbe” under the Rospotrebnadzor (Saratov city) for research purposes in 1983 and as a back-upstrain in case of its loss by other collections. The purpose of the work was to study the preservation of biological properties of freeze-dried Burkholderia pseudomallei С-141 strain after 11 years of storage. It was established that under optimal storage conditions (temperature of 4–8 °С, skimmed milk as a cryoprotectant) the strain remained viable and retained its biological properties during the wholeo bservation period. С-141 strain showed saccharolytic, oxidase, catalase and proteolytic activities, did not generate hydrogen sulphide, which is consistent with the melioidosis agent biochemical features. The strain was refreshed by passaging in golden hamsters and Burkholderia culture was isolated and freeze-dried. Burkholderia pseudomallei С-141 freeze-driedstrain was tested for quality parameters, records were made and the strain was deposited.

The paper presents results of our studies on isolation of bacteriophages active against Bordetella bronchiseptica. Three new bacteriophages were recovered from clinical material of animals with respiratory disease signs: vB_BbrS_2/200220.7.2, vB_BbrS_4/200220.7.1, vB_BbrM_5/200220.7.2. The lytic activity of isolated bacteriophages determined by the method of agar layers varied from (2.3 ± 1.4) × 10⁸  to (9.0 ± 0.2) × 10⁸  BOE/ml, and the lytic spectrum ranged from 61.5 to 76.9%. The bacteriophage titer stability was shown during 8-month storage of phage lysate with no preservative added. The morphology of bacteriophage negative colonies was tested in various nutrient media and analyzed based on two parameters: size and transparency. Dissociation of negative colonies into clear colonies, cloudy colonies, and clear colonies with cloudy halos was observed in the media. Plaques also varied in size from 0.6 ± 0.2 to 2.6 ± 0.1 mm. High levels of temperature stability were noted during exposure of bacteriophages to high temperatures ranging from +40 to +95 °C in 5 °C step. The study of specificity showed that the isolated bacteriophages lyse closely-related bacteria. In the course of electron microscopic testing of each bacteriophage such parameters as the average diameter of the head and the average length of the tail were determined. In accordance with the international classification of viruses by morphological characteristics the vB_BbrS_2/200220.7.2 and vB_BbrS_4/200220.7.1 phages have been assigned to the family Siphoviridae, vB_BbrM_5/200220.7.2 bacteriophage has been assigned to the family Myoviridae. The obtained results of in vitro studies have shown that the isolated bacteriophages can be prespective in veterinary use for phage therapy of Bordetella bronchiseptica-induced diseases.

Mouse embryonic stem cells are widely used as a promising material for producing of new cellular systems with desired properties in cellular and molecularbiology, pharmacology, virology, medicine, veterinary medicine and biotechnology. Each type of cells requires different electroporation conditions that are determined experimentally. Therefore, the main goal was to optimize conditions of electroporation with Neon® Transfection System, a new-generation device, by selecting and changing of various parameters (voltage, impulse width and number of impulses) to maximize efficiency of D3 embryonic stem cell line transfection and to maintain cell viability. The following parameters were found to be the most optimal for the said cells: impulse voltage– 1200 V, impulse width – 10 ms, number of impulses – 3. Under given conditions, viability of the cells after electroporation was 91%, and transient transfection efficiency (24 hours after electroporation) assessed based on bacterial β-galactosidase production was 88%. It was shown that with higher cell density any electroporation condition tested yielded higher transfection efficiency ranging between 34 and 88%. It was demonstrated that only 5 out of 12 tested protocols with different parameters could be successfully used for insertion of DNA plasmid carrying lacZ Escherichia coli gene into D3 cell line. Thus, the experiment results show the more optimal conditions can be selected experimentally taking into account available information on electroporation protocols for similar cell types recommended by the device manufacturer. Electroporation of mouse embryonic stem cells with the new-generation device can bean effective method for in vitro insertion of nucleic acids into the cells of interest to the researcher.