Recent variants of porcine circovirus type 2 (PCV2) were obtained from tissues of domestic pigs with porcine circovirus associated disease and from randomly selected wild boar samples from Serbia and Slovenia. A 450-base-pair nucleotide sequence was obtained by PCR from the ORF2. The derived nucleotide and amino acid sequences were aligned and compared to the corresponding region of closely related PCV2 sequences determined in previous years and retrieved from the GenBank. The 30 Serbian and 17 Slovenian PCV2 sequences clustered into three previously determined genotypes (PCV2a: 7), (PCV2b: 38) and (PCV2d: 2). Three major variable regions, concerning 29 amino acid position substitutions within the ORF2, were observed, which further supports the segregation of the detected strains into three separate genotypes. This study indicates that PCV2b is the predominant genotype in Serbia and Slovenia and the detected PCV2 strains are closely related to those previously described in Europe and in other parts of the world.

Abstract:Respiratory diseases are one of the most important problem in modern, intensive swine production, in the world but also in our country. Intensifying pig production increases frequency and economic importance of this disease, regardless to the measures for its control. Great economic losses are expressed through direct losses due to death and compulsory slaughter, reduced daily gain, a larger feed intake for averige daily gain, prolonged time of fattening, enlarged costs of treatment and a high percentage of light pigs in abattoirs.As a material for research we used the parts of respiratory organs (the lungs and mediastinal lymphonodes) deriving from 125 pigs in total. The evaluation included animals from: 11 industrial swine farms, four mediumsized swine farms, and swine deriving from 17 individual (private) backyards. Bacterial isolation was carried out by aerobic, anaerobic and microaerophyl microorganism cultivation. The identification included determination of their phisiological properties by biochemical characteristics. From the examined samples of respiratory organs, the most frequently were isolated Pasteurella sp. (26.57%), E. coli (26.57%), Streptococcus sp. (16.7%), Staphylococcus sp. (5.59%) and Klebsiella pneumoniae (4.90%). The solitary infective agens from total 72 examined samples was isolated (57.60%), while in 53 examined samples (42.4%) the presence of mixed infection was detected.

Classical swine fever (CSF) is a highly contagious viral disease of domestic swine and wild boars. The aim of the study was to examine samples of lymphoid tissues and brain for the presence of Classical Swine Fever Virus (CSFV) antigen in piglets that originate from vaccinated and unvaccinated sows, in order to compare the intensity of pathological lesions in conditions of different immunological status. A total of 20 crossbreed piglets of both sexes, aged 45 days were divided in three groups (G1, G2 and G3). Piglets of G1 originated from sows vaccinated with a live vaccine containing attenuated C strain CSFV. Piglets of G2 originated from unvaccinated sows. Two piglets of G3 originated from vaccinated and two piglets from unvaccinated sows and they served as the control group. All the piglets from G1 and G2 were intramuscularly inoculated with 2×10 5 TCDI/ 50 of CSFV, Baker strain and they died by the 22 nd day post inoculation. Immunohistochemistry was applied for immunolabeling E2 (gp55) glycoprotein of CSFV in the tonsils, mandibular lymph nodes, ileocecal valve and brain of all tested piglets. Differences were observed in the severity of lesions in the lymphoid tissue and the brain between G1 and G2 piglets. The present level of colostral antibodies was not able to protect piglets in G1 from the fatal outcome of the disease. Among others, this fi nding may also have an impact on vaccination policy in the future. Having in mind that vaccination of all domestic pigs with attenuated C-strain vaccine is still a mandatory control measure for CSF in Serbia, soon a non-vaccination policy should be harmonized with EU directives.

Aujeszky′s disease (MA) is an infectious viral disease, caused by suid alpha herpes virus 1, which displays a very broad host range, except humans and primates. Pigs are the only animal species that can survive the infection with the MA virus, which accounts for its ability to be latently infected. Although pigs are considered a natural host and the main reservoar of the virus, the spreading and transmission mechanism cannot be always detected. The aim of the paper was to evaluate the routes of transmission and spread of MA virus in the swine population with different immunological stutus i.e. depending on the vaccinal status. The material for this research consisted of the samples from four swine farms, with health disorders i.e. clinical signs suggesting MA disease. The applied research methods included: epidemiological and clinical evaluation, pathomorphological examination, virology testing of tissues originating from the dead animals and serological testing in order to evaluate the specific antibodies against MA. The obtained results indicate that purchasing breeding animals with different or unknown health status regarding MA, represents the main route of transmission and spreading of the infection. Besides vaccination, which represents one of the measure in MA eradication, it is necessary to apply strict trade control and checking the health status of herds from where breeding animals are purchased.

The aim of the paper was to evaluate the possible interaction between the presence of swine infectious diseases and low levels of mycotoxins in swine feed. The material for this research included the samples from three swine farms, where health disorders in different swine categories were detected. The applied research methods included: epidemiological and clinical evaluation, pathological examination, bacteriological and virological laboratory testing and microbiological feed testing, in order to examine the presence of fungi and mycotoxins by the method of thin layer chromatography. Beside this, the molecular diagnostic method, reverse transcripton-polymerase chain reaction (RT-PCR) and viral isolation was included. The obtained results support the existance of positive interaction between the mycotoxins and causative agents of bacterial and viral swine infective diseases. [Projekat Ministarstva nauke Republike Srbije, br. TR 31071]