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Open access

Dejan Vidanović, Milanko Šekler, Tamaš Petrović, Zoran Debeljak, Nikola Vasković, Kazimir Matović and Bernd Hoffmann

Abstract

Lumpy skin disease (LSD) is an important disease of cattle which is included in the OIE list of notifiable terrestrial animal diseases because of its great economic importance. The etiological agent is the Lumpy skin disease virus (LSDV).

In the control of LSD attenuated strains of LSDV and SPPV are successfully used as vaccine strains in infected areas. In the case of vaccination policy, due to the possibility of mild or systemic post-vaccination reactions in vaccinated animals, the application of diagnostic procedures that will rapidly and specifically differentiate LSDV field strains from LSD vaccine virus strains are extremely important. Rapidity in diagnostics and disposal of infected animals is one of the key factors in the prevention of spreading the disease.

In the presented study we have described the development and validation of two real-time TaqMan-PCR assays for a rapid, sensitive and specific detection of the virulent field LSDV strain currently circulating in the Balkan Peninsula. Specificity for the field strain and exclusivity for vaccine strains was tested on 171 samples from naturally infected and vaccinated animals.

The results of this study show that both developed real-time PCR assays are more sensitive than the conventional nested PCR in detecting field LSDV strains thus enabling rapid and high-throughput detection of animals infected with field strains of LSDV.

In conclusion, both KV-2 and FLI real-time PCR assays described in this study are simple, rapid, sensitive and suitable for routine use in a diagnostic laboratory and have the potential to replace conventional nested gel-based PCR assays as the standard procedure for the detection of field strains of LSDV in clinical samples.

Open access

Dalibor Todorović, Maja Velhner, Dubravka Milanov, Dejan Vidanović, Ljiljana Suvajdžić, Igor Stojanov and Dejan Krnjaić

Abstract

Resistance to tetracycline was studied in Salmonella Infantis isolated from 28 poultry farms in the Northern part of Serbia (The Autonomous Province of Vojvodina). A total of 18 isolates were resistant to nalidixic acid (NAL) and tetracycline (TET). The minimal inhibitory concentration (MIC) to TET, ranged from 1-256 mg/L. Namely, 13 isolates exhibited MIC to TET at 256 mg/L, in four of the isolates, the MIC was 128 mg/L and one isolate had MIC 64 mg/L. Ten isolates were exhibiting a MIC of 1mg/L. It was evident that Salmonella Infantis had also spread to breeders and layers. In this work, we detected the tetA gene and the corresponding tetR gene (encoding the repressor protein) as well as the truncated transposon Tn1721, which are responsible for the resistance to TET. The presence of the non conjugative transposons from the conjugative plasmid has facilitated the spread of resistance to TET in Salmonella. It was concluded that higher biosecurity practice in poultry farming presents the best option to eliminate infections caused by Salmonella spp. from poultry flocks in Serbia. A rational use of antimicrobials is necessary to prevent any further spread of Salmonella Infantis resistant clones.

Open access

Predrag Simeunović, Jevrosima Stevanović, Dejan Vidanović, Jakov Nišavić, Dejan Radović, Ljubodrag Stanišić and Zoran Stanimirović

Abstract

In this study 55 honey bee colonies from different Serbian regions were monitored for the presence of Deformed Wing Virus (DWV) and Acute Bee Paralysis Virus (ABPV) using TaqMan-based real-time RT-PCR assay. The results revealed the presence of DWV in each sampling location, and ABPV in 10 out of 11 apiaries. High frequency of DWV (76.4%) and ABPV (61.8%) positive samples in asymptomatic colonies can be the consequence of inefficient and postponed Varroa treatment concerning the role of this mite in the transmission and activation of honey bee viruses. The real-time RTPCR technique described in this paper is proved to be the most reliable method for this kind of investigation.

Open access

Mladen Rašeta, Vlado Teodorović, Olivera Bunčić, Vera Katić, Ivana Branković Lazić, Vladimir Polaček and Dejan Vidanović

Abstract

During the year 2012 a study was conducted on the hygiene of the production of broiler carcasses at three abattoirs in the Republic of Serbia. A total of 150 samples of broiler neck skin were examined and 17 salmonella isolates were recorded. Isolates were, by using the corresponding monovalent and polyvalent sera, determined according to type as Salmonella enterica subspecies enterica serovar Infantis (S. Infantis 6, 7, r, 1, 5). In the case of the disease in humans, 5 Salmonella samples of identical serovars were isolated. After that, 22 samples were tested for antibiotic resistance by the disk diffusion test. Isolates showed resistance to ampicillin and nalidixic acid (95.5%), tetracycline (91%), cefotaxime/clavulanic acid (68.2%), but not to ciprofloxacin, gentamicin, and trimethoprim/sulfamethoxazole. The degree of genetic similarity of isolates from diseased humans and broiler carcasses was determined at a molecular level. Cluster analysis revealed the presence of 7 profiles, while all isolates have 92% genetic similarity. Although there are differences in the antimicrobial resistance of isolates originating from diseased humans and neck skin of tested broilers, can not be excluded an epidemiological link, because in the dominant genotype SINFXB0001, established in 8 isolates from diseased humans (3 isolates), and the neck skin of broilers (5 isolates), a genetic similarity of 100% was recorded. Based on these results, the presence of S. Infantis on broiler carcasses can be considered a hazard to human health.

Open access

Božić Biljana, Polaček Vladimir, Vučićević Ivana, Vidanović Dejan, Vasković Nikola, Prodanov-Radulović Jasna and Aleksić-Kovačević Sanja

Abstract

During the epizootic of highly pathogenic avian influenza subtype H5N8 in Serbia in the winter of 2016-2017, the highest percent of mortality due to this infection was recorded in mute swans (Cygnus olor). Besides mute swans, avian influenza virus subtype H5N8 was also diagnosed in a small number of hens in rural households. Pancreatic tissues from avian influenza H5N8 positive mute swans and hens that died during this outbreak were collected to determine the character of morphological lesions and the distribution of the viral antigen in this organ. Macroscopic examination of the pancreas of mute swans revealed hemorrhages as well as necrosis, while there were no macroscopic visible lesions in the pancreas of infected hens. Despite the different macroscopic finding, microscopic examination of the pancreas of both infected bird species revealed lesions in the form of acute pancreatitis and multifocal acinar necrosis. The viral antigen was abundantly expressed in the cytoplasm and nucleus of necrotic cells, as well as in macrophages in both examined bird species. Immunohistochemical expression of the viral antigen in the pancreas was strongly consistent with histological lesions. According to the above described findings, it could be concluded that highly pathogenic avian influenza virus H5N8 has a high affinity to pancreatic tissue in both mute swans and hens and the distribution and the character of the lesions in the pancreas are similar in both bird species.

Open access

Vladimir Polaček, Dejan Vidanović, Biljana Božić, Žolt Beckei, Ivana Vučićević, Jasna Prodanov-Radulović and Sanja Aleksić-Kovacević

Abstract

The most important morphological characteristic of infections caused by M. avium subsp. hominissuis (MAH) is granuloma formation. The growth of mycobacteria is in accordance with anti-bacterial effector mechanisms of the host within granuloma. The most important cytokines for „orchestrating“the host defense are interferon γ (INF-γ), tumor necrosis factor α (TNF-α) and transforming growth factor β1 (TGF-β1). Myofibroblasts that make up a peripheral layer of granuloma largely express receptors for TGF-β1. This cytokine is believed to affect the induction of myofibroblast proliferation. The aim of this paper is to point out the importance of myofibroblasts in the formation and sustainability of granuloma during natural infection of pigs with M. avium subsp. hominissuis. Examinations have been performed on the samples of Lnn. jejunales, Lnn. ileocolici and Lnn. colici of 100 pigs with a positive tuberculin skin test. The molecular method confirmed the presence of a genome M. avium subsp. hominissuis. The microscopic examination of lymph node samples stained by the routine hematoxyilin-eosin (HE) method, showed the presence of granulomatous lymphadenitis. The method of double immunohistochemical staining revealed that myofibroblasts which express TGF-β1 receptor type I (TGF-β1RI) and α smooth muscle actin (α SMA) have an important role in the morphogenesis of granulomatous lymphadenitis in pigs infected with MAH.