Rabies is a dangerous zoonoticdisease that affects the central nervous system, causes encephalomyelitis and paralyses and Is almost invariably fatal. The disease causes significant economic losses associated with the death of animals, outbreak consequences, strict restrictions on domestic and international trade in livestock products, preventive and quarantine measures, laboratory tests. The World Organization for Animal Health recommends vaccination to control rabies. Taking into account that there is a lack of affordable high-quality vaccines to globally prevent and control the disease, stable, attenuated production strains of rabies virus with broad cross-activity against various variants of the pathogen shall be considered as ideal candidates to produce high-quality, safe and effective vaccines. Currently, someapproachesareappliedtoreducethevirusvirulenceandimprovesafetyof rabies vaccines. Reverse genetics is very popular now. It provides new approaches to study functions of a specific gene by analyzing phenotypic effects after direct manipulations with nucleotide sequences. The methods of reverse genetics have revolutionized molecular biology and have become apowerful tool to study genetics of RNA viruses. These methods are widely used to study rabies virus. The use of reverse genetics has made it possible to modify rabies virus production strains for manufacture of modern genetically modified rabies vaccines that induce a persistent and long-term immunity. The review briefly covers general approaches to development of viral vectors with the purpose to create genetically modified rabies vaccines.

The main advantage of transformed cell lines as compared to primary ones is that they allow generation of the stable material suitable for long-term research and practical use. Therefore, development of new continuous cell cultures from various animal tissues is of great practical importance. Results of examination of transformed cell lines derived from organs of domestic pigs (Sus scrofa L.) for their biological, cytomorphological and karyological features are described in the paper. The said cell cultures are confirmed to be susceptible to various animal viruses. Also, a procedure for preparation of new diploid cell culture from porcine spleen (SSs – Splеen Sus scrofa) is described. Based on the obtained data analysis it was concluded that the epithelial cells derived from trypsinized porcine spleens could be successfully immortalized. All transformed cell lines of porcine origin have similar morphology with predominated epithelium-like forms. Some of them – SPEV, А4 С2 , RSK – tend to adopt a spherical shape in suspension. Such cell lines as PSGK-30 and PPES cell lines form partial multilayer or they are characterized by significant monolayer compaction with pseudosyncytium formation. Only pseudodiploid cell culture (SPEV cell culture) tends to grow in suspension, it also grows in rotating culture flasks. Karyological transformations in different cell cultures stabilized at certain level. Spontaneous increase in chromosome numbers in the main population of transformed cell lines towards triploidy resulted in stabilization of culture properties and increase in proliferation. PSGK-30 cell culture has the highest modal class – 64 chromosomes. Near-diploid cultures (А4 С2 , RSK) demonstrate stable growth properties and are similar to SPEV cell culture in adopting spherical cell forms in medium, monolayer character and cell morphology. PK-15 cell culture having a distinct karyotype under different cultivation conditions while retaining other culture properties is found to be the most adaptive. A new transformed diploid SSs cell culture is developed by long-term incubation, subcultivation (more than 80 passages) and selection at the FGBI “ARRIAH” laboratory; it can remain diploid or may spontaneously become heteroploid-immortalized during further passaging. The cell hyperploidy is very likely to enhance telomerase activity, which in turn stabilizes immortalization and results in proliferative activity increase The cell viability has been maintained so far by regular reseedings (split ratio – 1:2–1:3) performed 1–2 times a week.

The etiology of the diseases affecting gastrointestinal tractofdogs is variable. The second most important enteric viral pathogen in the world after parvovirus is coronavirus (CCoV). Vast studies by scientists from different countries evidence the ubiquitous spread of coronavirus infection in dog populations. In this regard, the prevention of this disease is still an acute problem; firstly this means the development of effective vaccines, which can provide are liable protection from the infection. The aim of this work was to study the CCoV isolate cultural properties, the selection of cell cultures most suitable for its reproduction and optimization of virus cultivation parameters in sensitive cell lines. TheCCoV isolate recovered from the pathological material of a dead puppy with enteritis symptoms was used in the study. Seven continuousandtwoprimarytrypsinizedcellculturesweretestedduringthestudyanditwasestablishedthat the most sensitive cell culture for the reproduction of this isolate was continuous Crandell-Rees Feline Kidney Cells (CRFK) in which atypical cytopathic effect was notedon Day 2 of the cultivation. Virus infectivity titer in this culture was 3.58 ± 0.14 lgTCID50/cm3 . It was established that such cell linesas fel in espleen cells (FS) and primary trypsinized kitten spleen cells (KS) are also sensitive to the CCoV isolate but less than CRFK cells. Effect of such parameters as multiplicity of infection, cultivation time, inoculation technique, adsorption period and cell lineag eon coronavirus growth rate was studiedfor some selected cell cultures. It was concluded that CRFK and FS cells can be used for the propagation of viral material to develop diagnostic tools and vaccines against canineenteric coronavirus.

Leukemia is alarge group of diseases different in etiopathogenetic mechanisms and common in almost all mammalian species. There view focuses on feline leukemia, a common disease of domestic and wild felids (Carnivora, Felidae), being one of the main causes of their deaths. Feline leukemia pathogenesis and etiology are described; possible methods for the infection treatment and prevention, as well as possibility of using cats as a model for feline leukemia study areassessed. Feline leukemia etiological agent is a feline leukemia virus (FeLV), having single-stranded RNA genomesurrounded with icosahedral capsidformedbyp27 capsid protein monomers. Leukemia clinical man ifestations in felids depend on high virulence of the virus and the disease is characterized with pronounced clinical picture and multipleorgan dysfunction. Treatment of leukemia in cats is ineffective and is mainly aimedat maintaining the functions of the body organs and systems. Immunomodulators and chemotherapy are alsoused. Vaccination isusedas apreventive measure, but commercially available adjuvanted and non-adjuvanted vaccinesdo not confer effective protection from the infection. The leukemia virus is reportedin wildfelids includingrare and endangeredfeline species that is undoubtedly affects their population sizes. Despite veryfew data on leukemia, the reported cases show that leukemia in large cats is also severe and fatal. Feline leukemia, despite the accumulated of data, remainsan on going serious and unresolved problem not only for veterinarians, but also for ecologists, zoologists and virologists involvedin the research related to the feline family, study of retroviruses and biodiversity conservation on the planet. Furthe rapplied and fund a mental research and verification there of in the field of feline leukemia virus study, leukemia treatment and prevention are required.

To date, the reisreason to believe that, unlike classical a cuterespiratory virusinfections caused by adenoviruses, rhinoviruses, orthomyxoviruses, COVID-19 behaves completely differently. Firstly, the pathological process esare likely to be immune-mediated and the immun esystem quites lowly ensurest heelimination of the virus from the organism. Secondly, the dynamics of the diseases ymptom development and the duration of intestinal virusshedding after recovery give reason to believe that theSARS-CoV-2 infection is mainly localizedin the intestine. A possible reason isthat in the presence of proteolyticenzymes, viral particlesmature, hydrophilic aminoacids are removed from the surface of the virion, making it more hydrophobic and able to ad here to cells due to hydrophobic interactions. The presence of the ACE2 recept or mainly in the enterocytes of the ileumdoes not exclude the accumulation of coronavirusin lymphocytes, given that there are more lymphocytes in the gastrointestinal tract than anywhere else, this fact can beconsidered as another justification for the predominant accumulation of coronaviruses, including SARS-CoV-2 in the intestine. A distinctive feature of feline coronavirus infection and, in particular, infectious feline peritonitis, from human COVID-19 infection was considered to be the presence of effusion peritonitis as the main complication leading to death, while respiratory and card iovascular in sufficiency is more characteristic for humans. Never the less, cases of serous peritonitis in humans infected with COVID-19 have already been described. In the context of the analyzed model, theclinical case describedin the study allows principal possibility of exacerbation of chronic coronavirus infection in caseof re-infection (superinfection) and development of apredominantlylocal infection. 

Today, global attention is drawn to the samecommon problem – spread of the novelCOVID-19 infection. From the end of December 2019 novelSARS-CoV-2 virus spreadover the majority of the countriesandon 11 March 2020 the World Health Organization announced pandemic. GlobalspreadofCOVID-19 was not limited to the human population and the rewasa need to test pet sand farm animals, whowere in contactwith the humans. The reare more and morere portson SARS-CoV-2 detected in minks, ferrets, dogs, cats, tigers, lions and other animals. Today the key methodofCOVID-19 diagnosis is polymerase chain reaction, butall currently availabletest-kits are intended for the virus detection in humans. The paper demonstrates data on the development of thereal-timePCR-basedmethodforSARS-CoV-2 RNA detection in the biological samples collected from animals. During the research, an optimal system of primers and aprobe were selected, reaction conditions were tested, basic validation specifications (sensitivity, specificity, reproducibility) wereset. The validation results demonstrated that the method met all the criteria of the high-quality measurement/test method sand it can be used for diagnostic tests. Thetest-kitwas based of the method in tended for SARS-CoV-2 RNA detection in animal biological samples and it was put into the veterinary practice. Animal populations in different regions of the Russian Federation were subjected to the screening tests in order to detect the novel coronavirus genome. NoSARS-CoV-2 was reported in her bivorous animals in the Russian Federation. TheFGBI “ARRIAH” experts detected only one positive pet animal. 

The implementation of animal health improvement and disease prevention activities with respect to bovine leukosis involves a need for timely detection of cattle infected with bovine leukaemia virus (BLV) on livestock farms. That is why early diagnosis using more sensitive and highly accurate methods is of particular importance. The paper presents the results of cattle serum tests for bovine leukosis with enzyme-linked immunosorbent assay (ELISA) and immunodiffusion (ID), as well as the comparative assessment of their effectiveness. A total of 440 cattle blood samples were subjected to serological testing with immunodiffusion; 37 (8.4%) of them tested positive for bovine leukaemia virus. The cattle blood samples were submitted from the Kumtorkalinsky (127), Karabudakhkentsky (122), Buynaksky (89) Raions, from Makhachkala (56) and Kaspiysk (46). Seropositivity was 17 (13.4%), 8 (6.6%), 5 (5.6%), 4 (7.1%) and 3 (6.5%), respectively. For the comparative assessment of the diagnostic tests, 100 (5 ID-positive and 95 ID-negative) serum samples were taken and tested with ELISA. As a result, specific antibodies against BLV gp51 antigen were detected in 4 ID-negative serum samples. All ID-positive serum samples also tested positive with ELISA. All in all 9 virus carriers were detected with ELISA, that is 44.4% more than with immunodiffusion. Thus, enzyme-linked immunosorbent assay is characterized by a higher sensitivity, as compared with immunodiffusion, and allows for improved detection of infected animals. However, alongside the advantages, this technique has certain disadvantages, one of which is the high price of the diagnostic test kit for anti-BLV antibody detection and the equipment required. 

African swine fever is a transboundary disease of all members of Suidae family andit causes economic damage to the pigindustry and ecology of wild boar as a species. The ASF epidemiology is complex andit is specifiedby the mechanismsof the agent’s transmission in susceptible animal populations. Choiceof measure saimed to control and prevent the disease spreadin the wild boar population depends mainly on the routes of the disease introduction and stage or phase of the epizootic process. Prevention of the ASFV introduction from an infected region to a free one is the back bone in the infection prevention. Therefore, there search was aimed at the spatiotemporal analysis of African swine feveroutbreaks in the wild boar population in the Russian Federation in 2007–2022 and identification of geographical are as that poser is kof new disease epidemics. The analysis was performed using retrospective space-timescan statistics, which does not require data on the wild boar population and which can beused for the assessment of the possibility of new ASFoutbreak occurrence upon availability of just data on the reported disease case sand out breaks. As are sult of spatiotem poral cluster analysis, 24 clusters of ASF out breaks were identified based on the laboratory-confirmed data on the infection in boars found dead, and 22 clusters in hunted wildboars. The analysis results demonstrated spatial heterogeneity of the outbreak cluster distribution in population of wildboarsdied of the disease and a significant expansion of the passive surveillance geography. Importance and necessity of the enhanced passive surve illance of African swinefever in susceptible animals is demonstrated. The proposed methodcan beused for regular scanning of age ographic region for the presence of developing zone sand areasat risk of re-emerging ASFoutbreaks in the wildboar population at different spatial scales. 

Due to the increased role of opportunistic infections, mycobacterioses, parasitocenoses, etc. the detectability of nonspecific reactions to PPD-tuberculin has sharply increased, which makes it difficult to make a diagnosis and brings laboratory test methods to the fore. The aim of the study was to determine practical significance of blood-drop agglutination test in comparison with allergy test, and frequency of avian tuberculosis lesions on internal organs. For comparative assessment of these techniques 4,086 chickens were tested, including 2,000 young chicks aged 6–9 months and 2,086 adult poultry. In order to compare the results of allergy and serological tests, necropsy was performed for reacting chickens, identified using blood-drop agglutination test and demonstrating positive results using both methods. Low effectiveness of the allergy test in comparison with the serological test was established. The blood-drop agglutination test made it possible to additionally identify 311 adult chickens seropositive for tuberculosis in poultry farms. The effectiveness of this serological method in young birds and poor matching of results in comparison with an allergy test have been shown. The necropsy findings confirmed the practical significance of the serological test; generalized tuberculosis process was noted in all birds positively reacting in blood-drop agglutination test. The dependence of internal organ lesions on poultry-keeping conditions was determined in tuberculosis-affected farms in the autumn and spring periods. Internal organ lesions were found in 835 birds out of 1,072 tested poultry. In the autumn period the intestines were affected in most cases (57.2%), lung lesions were found in the least cases (8.2%), and in the spring period tuberculosis lesions were more often detected in the lungs (43.8%), less often in the intestines (35.5%). In the winter period, the morbidity predominantly occurs due to dust infection, and in summer, birds become infected via alimentary route, which explains the results obtained. The identification of a significantly larger number of diseased chickens, both in advanced form and at an early stage, makes it possible to recommend a blood-drop agglutination test for the diagnosis of tuberculosis. The involvement of internal organs directly depends on the poultry keeping system and should be taken into account when veterinary and sanitary measures are performed. 

Exposure to abnormally high temperatures in the Middle Urals has ledtochronic heat stress in cattle. Despitethe measures taken toprotect thedairy herdfrom overheating (fans, irrigationwith coolwater, livestocksunshades), the heatstressunderminedtheimmunityofanimals, thus, leadingtoan excessiverisein Salmonella population in the gastrointestinal tract, increasedin test in alpermeability, and could also bethecause of increasedvirulence of such serotypes as – Salmonella choleraesuis, that are not typical for cattle. The simultaneous presenceof twopathogensof Salmonella entericasubsp. entericaspecies: i.e. Salmonella enteritidis and Salmonella choleraesuis – causeda number of clinical and morphological changesin adultcows. In cows, the infection manifested itself by persistent diarrhea with mucus, reduced milkproduction and intoxication. In calves, the disease was accompanied by septic signs, severein toxication, hyperthermia (40.5–41.0 °C), severed ehydration (morethan 7%) and death. Histopathological examination of bovineparenchymal organs revealed changes typical for salmonellos is pathological process: specific salmonella granulomas were foundin parenchymalorgans (liver, spleen). Some pathological processestypical for sepsiswere foundin other parenchymalorgans (kidneys, heart). The nature of pathological changes in dicates that there is as epticprocess that spreads both hematogenically and lymphogenically, and the structure of granulomas most likely indicates that such apathogen as Salmonelacholeraesuis circulates in cattle. 

The paper covers the issues of organization of live animal transportation process in the Russian Federation as one of the factors of epidemiological risk associated with the spread of infectious animal disease pathogens. The legal framework, regulating the organization of live animal transportation using different vehicles, as well as quantitative data on live animal movements, taken from state veterinary information system “VetIS” (“Mercury” and “Cerberus” components) were analyzed. The analysis showed that live farmed animals are moved using all transportation means available, motor vehicles, planes, trains, ships as well as by driving. It was established that the major means of transport used to move live animals in the territory of the Russian Federation are motor vehicles. According to the analysis results 4.49 billion animals, including 4.41 billion poultry, 79.8 million large and small ruminants, pigs, horses, fur animals and bees were moved within the country in 2021. At the same time the number of issued veterinary accompanying documents for movements of cattle, poultry and pigs (i.e. in fact the transportations themselves) is much higher than the number of movements of other species. It was revealed that today only the movement of animals by railway is regulated in one way or another. The paper presents the suggestions to introduce the procedures aimed at improvement of biological safety and animal welfare during transportation. The results of the analysis performed can be used to optimize the control of animal transportation in the territory of the Russian Federation by competent authorities. 

The livestock industry is increasingly taking its place in the economy of the Russian Federation. Its export potential is actively growing. Already, up to 10% of agricultural products are exported to foreign markets. The demand for food steadily increases during crises, which in turn increases the role of the veterinary service, whose tasks include protecting the country’s territory from the introduction of infectious diseases of animals from foreign countries; implementation of measures to prevent and eliminate infectious and other diseases in agricultural, domestic, zoo and other animals, fur-bearing animals, birds, fish and bees, as well as the implementation of plans of the regional veterinary service in the field of animal husbandry. The article assesses the validity of the possibilities and use of modern methods of analyzing and predicting the spread of animal morbidity, identifying cause-and-effect relationships and the extent of the spread of particularly dangerous animal diseases. The authors propose to consider the possibility of using the mathematical method of hierarchy analysis as a scientifically sound decisionmaking support tool when assessing the risk of introducing trans-border infectious animal diseases into previously prosperous territories of the Russian Federation. This approach can be used in the process of choosing the most appropriate alternative from several risk assessment options. The Hierarchy Analysis Method (MAI) is a mathematical tool for a qualitative systematic approach to solving decision-making problems. This method was developed by the American scientist Thomas Lewis Saati in 1970, since then it has been actively developing and widely used in practice. The hierarchy analysis method can be used not only to compare objects, but also to solve more complex management and forecasting tasks.