Foot and mouth disease has a negative impact on economy due to the high cost of eradication campaigns and stringent measures imposed on domestic and international trade in animal products. Prevention and control measures include mass vaccination of susceptible animals and control of post-vaccination immunity level. Concentration of 146S particles, which are the main component affecting the vaccine immunogenicity, is determined during commercial scale production of FMD vaccines. The paper assesses feasibility of spectrometric analysis for indirect determination of 146S component concentration while measuring amount of FMDV RNA isolated after serological binding. This method is cheap, easy-to-use and makes it possible to determine indirectly concentration of FMDV 146S particles in inactivated vaccine raw materials within 3–4 hours. Study of cultural FMDV suspensions shows that the linear model С_146S = (3.9 × N_{RNA 146S + 566,783,689})/ 280,818,944,837 makes it possible to estimate FMDV 146S component concentration in the vaccine raw materials with the help of a spectrometric analysis. The actual results obtained in real-time reverse transcription – polymerase chain reaction (rtRT-PCR) were 97.0–99.9% consistent with the expected results of the spectrometric analysis used to determine cultural FMDV 146S component concentration. When compared to a complement fixation test, the actual results were 94.5–99.5% in line with the expected ones. The actual results for positive control were 99.0–99.6% in line with the expected ones. As expected, no FMDV genome or 146S particles were detected in the negative control sample.

Compliance with the existing purity and safety requirements for immunobiologicals can be effectively achieved by the use of serum-free nutrient media and specialised supplements of non-animal origin. The paper shows the possibility of using Sheff-Vax ACF® supplements (Kerry, Inc., Ireland) for ВНК-21/SUSP/ARRIAH cell cultivation and FMDV reproduction. By passage 7, cell concentration and growth rate with Sheff-Vax Plus PF ACF were found to be 40–60% higher than with Sheff- Vax PF ACF and Sheff-Vax Plus ACF. No differences were observed as regards changes in pH. During FMDV reproduction in the cells, it was found that the number of 146+75S components in the test samples containing 1 million cells was 2.3–2.4 higher compared to the controls. Cells cultured with the use of Sheff-Vax Plus PF ACF supplement had normal morphology and multiple dynamic protrusions. In the presence of this supplement, growth rate and suspension concentration in the test and control samples became equal by passage 7. The number of immunogenic components of FMDV reproduced in the cells grown using Sheff-Vax Plus PF ACF was 20–30% higher than in the cells grown using other supplements. ВНК-21/SUSP/ARRIAH cell concentration and growth rate in the presence of specialised supplements were found to be lower than those in the control samples with serum and blood protein hydrolysate added to the nutrient medium. The virus yield from 1 million cells was higher in the culture grown using Sheff-Vax ACF supplements. Sheff-Vax Plus PF ACF was found to be the most suitable for ВНК-21/SUSP/ARRIAH cell cultivation and FMDV reproduction in the said cells out of the three tested supplements.

The purpose of these studies was to optimize RHDV type 1 and 2 (RHDV1 and RHDV2) inactivation modes to use the obtained antigens in inactivated vaccines and diagnosticums. The inactivating effect of aminoethylethylenimine and β-propiolactone was studied in different concentrations in correlation with the exposure time and temperature. The correlation between the inactivating effect of the compound used and the accepted test conditions (concentration, temperature, and exposure time) was studied on a group of rabbits, each of which was injected intramuscularly with 1 cm3 of the inactivated material sample. At the end of the maximum exposure interval, a control sample of the viral material, kept under the same conditions without any inactivant added was similarly tested. Lethality was considered to evaluate the damaging action in the test and control groups: L = m/n, where m is the number of dead animals; n is the total number of rabbits in the group for testing of the inactivated material sample. The postmortem diagnosis was confirmed by testing the rabbit liver tissue homogenate for relative antigens using ELISA. It was found that aminoethylethylenimine and β-propiolactone did not have the same effect on the studied variants of the virus. In order to preserve at maximum the antigenic structures of the virus, the following inactivation modes were considered to be optimal: for RHDV1-aminoethylethylenimine at a concentration of 0.3% at 37 °C, exposure time – 72 hours, or β-propiolactone at a concentration of 0.1–0.3% at 25–37 °С, exposure time – 24–48 hours; for RHDV2 – aminoethylethylenimine at a concentration of 1% at 37 °C, exposure time – 72 hours, or β-propiolactone at a concentration 0.3% at 25 °С, exposure time – 24 hours.

To reduce the incidence of acute respiratory viral infections in cattle, routine vaccination of mother cows is carried out. There is a direct dependence of the passive immunity level in calves on the vaccination efficacy in cows. The paper presents the results of a study of colostral immunity in calves and post-vaccination immunity in cows against the agents of acute respiratory viral infections in agricultural facilities located on the territory of the Ural and Volga Federal Districts. In the farms under study (n = 10), cattle are vaccinated with inactivated vaccines: “COMBOVAC” and “COMBOVAC-R” (OOO Vetbiokhim, Russia), “HIPRABOVIS® 4” (Laboratorios Hipra, S. A., Spain). The study of postvaccinal immunity level in cows showed that the levels of antibodies to infectious bovine rhinotracheitis virus (5.3–8.0 log2), bovine viral diarrhea virus (3.5–4.8 log2), bovine parainfluenza-3 virus (6.8–8.5 log2) and bovine respiratory syncytial virus (4.2-4.5 log2) in cattle confer protection. When evaluating the results of serological diagnostics of passive immunity in calves to acute respiratory viral infections, it was found that the level of colostral antibodies in them is lower than the level of post-vaccination antibodies in cows: to infectious bovine rhinotracheitis virus by 34.2–58.8%; to bovine diarrhea virus by 37.5–45.0%; to bovine parainfluenza-3 virus by 14.7–35.4 and to bovine respiratory syncytial virus by 23.5-42.2%. To ensure epizootic favourable situation, it is proposed to adjust the schedules of vaccination against bovine diseases in herds, infected by acute respiratory viral infections for dairy farms under study.

For the purposes of tuberculosis eradication on any tuberculosis-infected farm, it is necessary to identify tuberculin anergic animals, being a potential source of the infection. The purpose of this study was to analyze the role of complement fixing and haemagglutinating antibodies for the detection cattle infected with bovine tuberculosis (TB). 977 cattle of different sex and age groups on two tuberculosis-infected farms were tested thrice over time. After 35 days all tuberculin reactive cattle (132 animals; 13.5%) were subjected to complex testing using allergy and serology methods. After 40 days, (Stage 3) animals demonstrating apparent specific antibody activity and low cell immunity were tested. Allergy tests were proved to be non-informative to diagnose tuberculosis on infected farms. Complement fixing and haemagglutinating antibodies were found to be active in tuberculin anergic animals. A higher antigenicity of Ukrainian RIEVM TB antigen complex as compared to Siberian RVI one was revealed by complement fixation test as well as by indirect haemagglutination test using VIEV polysaccharide antigen; the detection rate was 68 (7.0%), 28 (2.9%) and 299 (30.6%) respectively. The correlation between seropositivity and immunoreactivity was not established. Animals, positive in complement fixation and indirect haemagglutination tests, did not react to tuberculin. Nineteen out of twenty tuberculin reactive animals showed post mortem lesions, consistent with their seropositivity during post-mortem inspection; moreover, the postmortem lesions of animals, positive in complement fixation test using Siberian RVI antigen, were consistent in all cases. The results obtained suggest a high performance of allergy test and serological test combination and a promising potential of their complex use for tuberculosis diagnosis in cattle.

Bovine respiratory syncytial virus (BRSV) is one of the etiological agents of respiratory diseases. The agent spreads widely in all the countries with intensive livestock farming and can cause pathologic changes in respiratory system either alone or in combination with other viruses and bacteria. It is a matter of crucial importance to study spread of the agent on large milk farms, to detect it in the internal organs of infected animals, and to quantify virus accumulation in them. The purpose of the research was to study peculiarities of RS infection spread, frequency of the virus detection in biomaterial samples (both alone and in associations with infectious bovine rhinotracheitis (IBR) and bovine viral diarrhea/mucosal disease viruses (BVDV) and with Pasteurellaceae bacteria) on large milk farms affected by respiratory animal diseases; and to determine virus concentration in the respiratory organs. BRSV alone was reported in 9.2% of the tested biomaterial samples, as associated with IBR and BVDV it was reported in 1.4% and 5.2% of samples, correspondingly. The number of samples containing simultaneously BRSV and Pasteurellaceae bacteria was 10.8%. The virus was reported in a maximum of 26.6% of the tested samples. With the help of real-time PCR the virus genome was detected in lungs (13.1%), in exudate from trachea, bronchi and nasal sinuses (6.0%), in nasal discharge (4.0%) and in bronchi (1.7%). The virus was seldom detected in trachea and bronchial mucosa (1.1%) and in pulmonary lymph nodes (0.8%). Quantification of BRSV RNA demonstrated that maximum virus accumulation was observed in lungs and nasal charges and it confirms data on its tropism to pulmonary interstitium.

In 2019, the situation regarding Newcastle disease in the Russian Federation worsened radically due to the spread of NDV subgenotype VII-L throughout the country from the Primorsky Krai to the Kursk Oblast. As a result, 17 infected settlements with backyard farms where unvaccinated poultry was kept were registered. In this study, immunogenicity of the vaccines produced by the FGBI “ARRIAH”, as well as the effectiveness of various vaccination schedules to prevent genotype VII NDVs, relevant for the Russian Federation, was studied. It is known that the currently circulating ND agent is significantly more virulent compared to the viruses isolated in previous years, and it is able to bypass the immunity provided by live vaccines. Test results demonstrated that the vaccines against genotype VII NDVs produced by the FGBI “ARRIAH” are highly immunogenic, which allows to effectively prevent the disease when using them as part of a standard vaccination schedule. A 2-dose vaccination schedule using live vaccine from the La Sota strain as well as the “complete” vaccination schedule using inactivated vaccines provides immunity in 100% of chicks. The use of live vaccines in a single- and double-dose vaccination schedules prevents mortality and clinical disease in poultry, but does not prevent virus replication, while the addition of an inactivated vaccine to the immunization schedule does prevent the replication of the virulent virus. Thus, the use of domestically produced live and inactivated vaccines, primarily the ones containing the La Sota strain, with the following control of the immunity level and booster vaccination, if required, is the main tool for the disease control.

The paper presents the results of the cestodiasis epidemic situation in domestic reindeer in the farms of the Murmansk Oblast. The studies were performed in 2018–2019 during the routine slaughter of reindeer at slaughter houses APC “Tundra” and APC HFE SEN “Olenevod” located in settlements Lovozero, Krasnoschelye, and Sosnovka. Totally 4,048 carcasses of domestic reindeer were tested, 2,812 out of them – in Lovozero, 396 – in Sosnovka, and 840 – in Krasnoschelye. During the meat inspection the parenchymal organs were examined for cestode cysts. When detected they were sampled and gross specimens were prepared using standard parasitological methods. 56 samples of internal organs of deer suspected in tapeworm infestation were collected from the inspected carcasses, in 25 of them tapeworms were detected and in the rest of the samples parasites were not detected. The tapeworm species were determined at the Department of Veterinary Biosiences, Faculty of Veterinary Medicine, University of Helsinki. The test performed revealed echinococcosis (Echinococcus canadensis) and cysticercosis (Taenia hydatigena). Most lesions were detected in liver where the agent’s larvae cysts are observed. It was established that the level of domestic reindeer infestation with the agents of cysticercosis in APC “Tundra” was 0.5%, echinococcosis – 0.04%, in APC HFE SEN “Olenevod” cysticercosis was diagnosed in 0.81% cases, echinococcosis was not detected. On the whole 0.62% of reindeer on reindeer farms were infested with cestodes. Measures taken for prevention of helminth infestation in domestic and farm animals bear good results.

The paper demonstrates morphometric and densitometric parameters of microbial biofilms recovered from lambs with digestive disorders. Changes of quantitative and species composition of the intestinal microbiocenoses in the lambs with digestive disorders were compared with the ones of the clinically healthy lambs. Light microscopy results demonstrated formation of three-dimensional biofilm structure in the form of dense grid consisting of gram-negative and gram-positive bacteria, yeast cells, hyphas and pseudohyphas surrounded with intracellular polymer matrix. Presence of blastospores aided to the increased number of cells attached to the substrate, and biofilm was formed, which consisted of rod and round cells attached to the microfungi cells. In the process of dispersion that occurred during the destruction of the intercellular matrix and bacterial and yeast cell detachment, branched structures separated from the microcolonies and colonized microorganism- free regions of the substrate. The intensity of biofilm formation by the microorganisms under study was evaluated by optic density measurement in 48 hours of cultivation. Fluorescence microscopy results demonstrated that the dynamics of changes of the viable microbial structures was specified by intermittent periods of increased or decreased biofilm formation intensity. Cells characterized by active growth and replication and forming alternating subpopulations were detected in the examined microbial cultures. When determining the viability of the microorganisms in the biofilms, the viable (green fluorescence) and non-viable (red fluorescence) cells were differentiated.

This review article summarizes current understanding of the microbiota development in neonatal mammals based on the results of modern experimental studies in animals focusing on three aspects: initial colonization, microbiota effect on the immune function of the developing newborn animal intestine and external factors influencing the microbiome shaping during the juvenile period. The presented study results confirm that the microbial landscape correction is the most important factor for animal health improvement since healthy microflora contributes to the intestinal infection frequency and intensity reduction, and this, in turn, minimizes the use of antibiotics. The microbiome is known to have an impact on the immune system development, metabolic processes and even on the ethology, so an atypical microbial population can cause immune and metabolic disorders. The active interaction between microorganisms and the host organism begins already at birth. Even different modes of delivery (caesarean or vaginal delivery) may determine the initial colonization of the newborn. The animal genetics, nutrition and environment also influence the intestinal microbiota development. In this regard, further studies of probiotics are important to understand their efficacy for diarrhea prevention and treatment, their use as an alternative to antibiotics as well as for enhancement of the animal resistance to stress factors.

African swine fever (ASF) is an infectious disease of domestic and wild pigs, which went beyond its natural range (African continent) in the XXI century and since 2007 (emergence in Georgia) has spread to many European and Asia-Pacific countries. According to the immediate notifications and follow-up reports, by early 2021 Europe accounted for about 68% of globally reported outbreaks. However, the greatest losses in the pig industry were inflicted by the outbreak recorded in Asia in 2020, when 6,733,791 animals died that accounted to 82% of the total global losses due to ASF. Just after several years of the current ASF epizootic, without any vaccine or treatment available, it became clear that major problems for the pig industry (mostly for small farmers) as well as destabilization of the global market of pig products were unavoidable. In this regard, in 2014 (Bern, September 2014) a regional standing group of experts on African swine fever (SGE ASF) was established under FAO/OIE GF-TADs umbrella. The aim of the group is to foster closer collaboration between the affected countries, increase transparency and share experience in prevention and control. The work of the permanent expert ASF missions under the GF-TADs umbrella has proven effective and become a model for other regions. A similar group was established in Asia in April 2019 to counter rapid spread of the disease in the Asia-Pacific region, where more than 60% of the world’s pig population is concentrated, and a new permanent ASF expert group for the Americas is being considered. The many-year efforts resulted in the establishment of the FAO/OIE/GF-TADs platform as a progressive mechanism to combat such transboundary disease as African swine fever.