African swine fever specific prevention means have not been developed yet. However, it is necessary to study the function of definite viral proteins, their role in immune response morphogenesis and induction to determine the components to be included into ASF protection drugs. It was established that p54 and p30 proteins participate in virus penetration and internalization and are able to induce protective antibodies in immunized pigs. The inoculation of these proteins into ASFV-infected cell culture has an impact on virus reproduction to different extents. The results of the study of purified recombinant protein p30 effect, derived from E. coli clone, containing pET32b(+)/р30 plasmid, on ASFV in vitro reproduction are presented. The greatest decrease, including complete inhibition of virus reproduction, was observed when 300 ng of p30 were inoculated into porcine spleen and marrow primary cell cultures, infected with the ASFV Krasnodar 07/17 isolate at the dose of 100 HAU per plate (~ 0.01 HAU per cell). It was noted that if the mixture of p30 and p54 was inoculated into a sample, the virus reproduction was greater compared to the use of only p30.

Spread of porcine epidemic diarrhea and its increased threat for the pig industry necessitate development of advanced techniques for the disease diagnosis. Use of recombinant antigens of the disease agent seems prospective. The recombinant antigen-based indirect enzyme-linked immunosorbent assay has been developed for the detection of antibodies against porcine epidemic diarrhea virus. The research performed allowed for determination of all necessary test conditions. Basic features of the developed method were determined during its validation. The test precision was above 90% pursuant to its repeatability and reproducibility, diagnostic specificity of the test amounted to 99.47%, and its sensitivity as compared to commercial ID Screen PEDV Indirect (IDvet, France) was 92% with very good compatibility of the two tests (k-criterion – 0.88) – 92%. The test-system demonstrates high stability upon the change of the key test component.

An indirect variant of ELISA used for detection of antibodies to nonstructural proteins of the FMD virus in porcine blood sera was developed. The results of the validation showed that the developed method is characterized by high sensitivity, specificity and reproducibility. When testing the blood serum panel obtained from experimentally infected animals, the method allowed to detect antibodies to FMD virus in 7 of 18 sera collected on day 6 post inoculation, in 13 of 19 sera – on day 7 post inoculation, in 16 of 19 sera – on day 8 post inoculation and in all 76 sera obtained on days 9–12 post inoculation. The diagnostic specificity of 3AB-ELISA was 100% when testing 100 knowingly negative blood sera from pigs imported to Russia from Norway. High specificity and sensitivity of the method, established during the development of the method, are confirmed in the course of routine diagnostic tests.

The paper describes the results of testing of biomaterial from domestic pigs and wild boars by real-time PCR used for African swine fever virus genome detection, carried out in the FGBI “Federal Centre for Animal Health” (Vladimir). In 2017 8,500 samples from 44 subjects of the Russian Federation were tested within the framework of the state laboratory monitoring. African swine fever virus genome was detected in 504 samples. In 2017 ASF outbreaks were registered in the Urals and Siberian Federal Districts of the RF for the first time. The conducted research and persistent ASF infection in the territory of the RF have demonstrated the need for further surveillance in the populations of susceptible animals. Development, organization and implementation of the program for ASF spread surveillance in wild fauna remains a high priority. It is necessary to create and implement sampling schedules with uniform sampling of biomaterial and submission of the collected samples to the research laboratories for timely ASF outbreak containment at the regional level.

Porcine pleuropneumonia is an infectious contagious disease caused by bacteria Actinobacillus pleuropneumoniae. Currently, the disease is widespread in many countries with well-developed pig production. The disease causes significant economic damage to farms due to the large mortality and expenses for treatment of diseased pigs and implementation of veterinary and sanitary measures. Due to increased number of Actinobacillus pleuropneumoniae cases in pigs, and the emergence of actinobacillus-resistant forms, it is necessary to perform a more thorough study and discussion of this problem. The disease epidemic surveillance is based on continuous monitoring aimed at porcine Actinobacillus pleuropneumoniae identification, confirmation and registration, determination of its characteristics and trends in development of sensitivity to antimicrobial preparations. The article addresses the topic of antibiotic use and the antibiotic resistance of microorganisms, which is actual not only for veterinary medicine but also for medicine. The model of swine Actinobacillus pleuropneumoniae was used to study the reasons of antibiotic resistance. Possible approaches to overcoming the resistance of actinobacilli to antibiotics have been discussed. The prospects for the use of antibiotics were discussed in detail to cope with this problem. Targeted surveillance, aimed at monitoring and collecting information on the prescription of antibiotics is of great importance for the solution of the problem of antibiotic resistance. The information obtained from the monitoring can be used for development of the plan and strategy for the use of antibacterial preparations (preparation selection, dose, route of administration, frequency, number of courses), development and implementation of more effective approaches to the treatment of Actinobacillus pleuropneumoniae in pigs, control of the antibiotic-resistant bacteria occurrence and spread.

Avian infectious bronchitis virus is a cause of major economic losses in poultry industry. However, control of the virus is very complicated due to its high variability. The mutation frequency in the hypervariable region of the S1 gene of the virus isolated from the vaccinated birds annually amounts to 1.5%. Long-term observations of the circulation of IBV isolates detected in a number of poultry farms demonstrated that the virus genetic lineages circulating on the poultry farms could eventually change. This stipulates the need for the continuous monitoring of the virus isolates for the prevention schedule optimization. The paper demonstrates test results of 840 biological samples collected from chickens on the poultry farms in Russia and some CIS countries in 2015–2017. From 311 positive samples 147 IBV isolates were recovered, the majority of which belonged to eight genetic lines of GI genotype: GI-1, GI-12, GI-13, GI-14, GI-16, GI-19, GI-22, GI-23. Moreover, recombinant isolates were detected as well as variant isolates that belonged to none of the known genotypes.

The histological study results of the thymus structure of Pekin ducks during administration of DAFS-25k feed additive are presented. It has been established that the thymus is  a  morphologically mature and actively functioning organ in  one-day-old Pekin ducklings. With age an  increase in the size of thymus lobules was observed in ducklings in the control and experimental groups but under the influence of selenium the cortical area increased more intensively. 45-day-old ducklings in the experimental group demonstrated a reliable increase in the ventricular-brain ratio mainly due to the expansion of the cortical area. The surface of the cortical substance did not change in intact ducklings, the tendency of extension in the surface of the brain substance was observed, which at that age is a sign of an accidental involution associated with the onset of a plumage change from juvenile down to primary feathers. Under the influence of selenium in the thymus of the ducklings of the experimental group the processes of accidental involution are leveled, the processes of synthesis of thymopoietins and proliferation of thymocytes are more active. Up to age of 75 days there is active proliferation of thymocytes in the thymus of ducklings of both groups; however reliably higher parameters of ventricularbrain ratio under the influence of selenium were observed in the experimental group, there was a clear boundary between them, as well as significantly higher quantity and size parameters of Hassal’s corpuscles were noted. From the age of 90 days signs of age involution in the organ were observed, and in the experimental group these processes were going more physiologically in accordance with the age of the birds. Introduction of the organic and selenium additive DAFS-25k in the diet of ducklings at a dose of 1.3 mg/kg of feed promoted the increase of the functional activity of the thymus that leveled the development of accidental involution and optimization of age involution.

The data on experimental infection of 6-week-old Big-6 cross turkeys with an epidemic A/duck/Altai/469/14 H5N1 clade 2.3.2.1c strain of avian influenza virus are presented. The characteristics of the infection process in birds inoculated intranasally at a dose of 5.0 lg EID50/0.5 cm3 are described with an indication of the incubation period and the mean time of death. The pathomorphological changes at the tissue and cellular level are shown based on histological and immunohistochemical studies of fragments of respiratory, digestive, cardiovascular, nervous, excretory, lymphoid and muscular systems of experimental birds. The testing was carried out using paired preparations of paraffin-embedded tissue sections from experimentally infected and healthy turkeys. One sample was subjected to histological staining using hematoxylin and eosin dyes, and its duplicate was subjected to immunohistochemical assay using a preparation of polyclonal antibodies as primary antibodies against the ribonucleoprotein of avian influenza virus. The results of histological and immunohistochemical studies are photodocumented and presented in the paper. Inflammatory and necrotic lesions of varying severity are detected in the preparations of the trachea, lung, muscular stomach, glandular stomach, small intestine, large intestine, pancreas, brain, cerebellum, heart, kidneys, liver and spleen of turkeys. Immunohistochemical analysis showed the greatest distribution of the influenza virus antigen in the cerebral endothelium, cerebellar Purkinje neurons, acinar cells of the pancreas and in myocardiocytes of the heart. In the course of the experiment it was established that A/duck/Altai/469/14 H5N1 caused a generalized form of infection in turkeys with clinical and pathologic lesions characteristic of highly pathogenic avian influenza.

Lumpy skin disease is an economically significant disease as it results in decrease in weight gain and milk yield, abortions, mastitis, reproduction disorders, animal emaciation, lesions of respiratory organs and in some cases – death. Today the disease is included in the OIE list and is subject to obligatory notification. The emergence and spread of the disease in the Russian Federation necessitated performance of tests in the framework of laboratory diagnosis method improvement. The test-system based on the indirect “Sandwich” ELISA for diagnosis of lumpy skin disease allowing performance of biomaterial tests within 24 hours was for the first time developed in Russia. The test-system development included antibody preparation in laboratory animals (rabbits and guinea pigs), selection of optimal dilution of capture and detection antibodies, composition of a buffer solution and conditions of the reaction procedure. 50 samples of initial culture antigens of the lumpy skin disease virus as well virus-containing suspensions collected on different stages of purification and concentration were tested using this technique. To confirm the ELISA results all analyzed samples were tested using RT-PCR. Besides, the virus infectivity titer was determined by titration in YaDK-04 (Goat gonad cells). The test specificity was 100%, and analytical sensitivity – 3.5 lg TCD50. The developed “Sandwich” ELISA allows performing tests of 24 antigen samples at 1:2–1:16 dilution simultaneously using 96-well plate and it can be used for lumpy skin disease diagnosis.

Pneumonia-associated mortality of different monkey species in captivity in 2017 has been analyzed. The animal death frequency and seasonality was demonstrated. Pneumonia-associated mortality in baby monkeys and old monkeys exceeds the mortality of infants and mature animals. The maximum pneumonia-mortality rate in monkeys was observed in February, April and May. The spectrum of microorganisms recovered from lungs of dead animals was identified. The prevailing bacterial flora detected in case of pneumonia was Staphylococcus aureus (43.1%) and Escherichia coli (34.9%), which were detected both in monoculture and communities. One of the peculiarities of pneumonia in monkeys is high occurrence of polymicrobial communities. Most frequently S. aureus is observed in combinations with E. coli (52.5%). All recovered S. aureus cultures were methicillin-sensitive and did not have gene mecA in their genome. During performance of bacteriological tests of autopsy material the lung tissue samples can get contaminated with the foreign flora that’s why it’s quite difficult to speak about the role of these and those microorganisms as major disease agents.

Listeria monocytogenes is one of the major food contaminants causing the illness, called Listeriosis. Listeriosis incidence is much less, than the number salmonellosis and campylobacteriosis cases, but the clinical disease is significantly more severe and has a higher mortality. That’s why the development of species-specific PCR techniques to detect L. monocytogenes genome is a topical task. L. monocytogenes bacteria genome detection technique using real-time polymerase chain reaction (qRT-PCR) was improved. The amplification target was a highly specific and suitable for qualification of all strains iap gen, coding L. monocytogenes р60 surface protein. Optimum magnesium concentration (6 mM) and primer annealing temperature (57 °С) were selected. The sensitivity and specificity of the technique were identified. Detection threshold was 120 target molecules. The results obtained demonstrate that optimized qRT-PCR version, based on iap gen amplification, enables to detect L. monocytogenes in animal product and food samples. Optimized qRT-PCR-based screening tests ensure rapid and reliable results.

The results of comparative studies of feline viral rhinotracheitis virus for its culture properties in primary and continuous cell cultures of feline origin (FK, FK (subculture), CrFK, FS, CC-81, FC/Tg) are presented. It was found that viral rhinotracheitis virus replication, irrespective of the route of infection and the culture technique, was consistent and practically equal in susceptible cell cultures. The most pronounced cytopathic effect (more than 75% monolayer degeneration) was observed in all types of cell cultures in 48–72 hours of cultivation. However, the accumulation of feline viral rhinotracheitis virus Grand strain was highest when preliminary adsorption occurred within the specified period of time, monolayer cell cultures were infected with the virus at a dose of 5.5 lg TCID50/ml and roller bottle cultivated, and the рН of the medium was maintained at 7.0–7.4. Single freezing of the virus at a temperature of minus 60 degrees Celsius upon the completion of the cultivation cycle (during 60–72 hours) and its thawing were found to significantly increase the virus titre by 0.5 lg TCID50/ml.