National Diagnostic and Research Veterinary Medical Institute

Sofia, Bulgaria

National Diagnostic and Research Veterinary Medical Institute

Sofia, Bulgaria

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Dimitrov K.M.,National Diagnostic and Research Veterinary Medical Institute | Manvell R.J.,Veterinary Laboratories Agency Weybridge | Goujgoulova G.V.,National Diagnostic and Research Veterinary Medical Institute
Avian Diseases | Year: 2010

Newcastle disease virus (NDV) and avian influenza virus (AIV) are pathogens of major economic and social importance, and the diseases they cause are often devastating, particularly in domestic poultry. Both viruses are naturally found in a wide variety of wild birds, particularly aquatic species, where asymptomatic infection typically occurs. Wild birds are therefore considered to be a natural reservoir for both viruses. Wild birds kept in captivity are in an environment that promotes transmission of infection with both influenza and Newcastle disease viruses. This report describes a survey for the detection of antibodies against Newcastle disease and avian influenza A viruses using the hemagglutination inhibition test in samples from 88 wild birds from 38 species in four Bulgarian zoos. Samples with positive results against NDV were also tested against avian paramyxovirus type 3 (APMV-3). Real-time reverse-transcriptase PCR was also performed to detect viral RNA of NDV and AIV among 127 wild birds from 57 species from the same zoos. In 13 samples from seven avian species (ten birds from the family Phasianidae, two from the family Numidae, and one from the family Columbidae), antibodies against APMV-1 were detected. Seven birds, whose sera were APMV-1 positive, had been vaccinated. The other six birds (five Phasianidae representatives and one of the Columbidae family) had no immunization history. No antibodies against both H5 and H7 AIV and against APMV-3 were detected, and no RNA of NDV and AIV were detected. © 2010 American Association of Avian Pathologists.


Daskalov H.,National Diagnostic and Research Veterinary Medical Institute | Stoyanchev T.,Trakia University | Santo R.,Kobe University
Bulgarian Journal of Veterinary Medicine | Year: 2011

Meat and cheese samples, artificially contaminated by three bacterial species: Listeria monocytogenes, Escherichia coli and Staphylococcus aureus were investigated by both microbiology and near infrared spectroscopy (NIRS). The incubation of samples at 8 °S{cyrillic} for 14 days did not result in significant increase in the number of inoculated microorganisms. During the entire experimental period, microbial counts remained within 101-103 CFU/g product. Regardless of the low bacterial contamination, NIRS analysis has successfully distinguished the contaminated samples by the SIMCA model and exhibited specific spectral differences that could be used to differentiate the specific classes according to the bacterial species.


Orozova P.,National Diagnostic and Research Veterinary Medical Institute | Sirakov I.,National Diagnostic and Research Veterinary Medical Institute | Petkov I.,National Diagnostic and Research Veterinary Medical Institute | Crumlish M.,University of Stirling | Austin B.,University of Stirling
FEMS Microbiology Letters | Year: 2012

Captive snakes, that is, a Jamaican boa (Epicrates subflavus) a yellow anaconda (Eunectes notaeus) and a corn snake (Pantherophis guttatus guttatus), died with signs of bacteraemia including the presence of petechial haemorrhages in the mouth and gums and haemorrhages in the lung, spleen and intestines. The abdomen and anus were swollen with bloody-tinged mucus in the colon. Aeromonas hydrophila was recovered in dense virtually pure culture growth from the internal organs. Characterization of the isolates was by phenotyping and sequencing of the 16S rRNA gene (sequence homology of 99% with A. hydrophila) with outputs confirming the identity as A. hydrophila. Pathogenicity experiments confirmed virulence to frogs (Rana esculenta) and rainbow trout (Oncorhynchus mykiss). © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.


Arnaudova-Matey A.,University of Forestry | Yankovska T.,Central Laboratory of Veterinary Control and Ecology | Kirilova T.,Central Laboratory of Veterinary Control and Ecology | Todorova K.,Bulgarian Academy of Science | And 4 more authors.
Bulgarian Journal of Agricultural Science | Year: 2013

35-day tests with broiler chickens treated with Bulgarian iron methionate administered through the food compared to the iron sulphate (heptahydrate) in doses of 60 ppm and 300 ppm were conducted. The test involved 55 broiler chickens aged 10 days, divided into 5 groups of 11 chickens. The tests started on May 21st, 2012 and continued 35 days. The basic mixed feed was prepared by using a recipe for growing broiler chickens and an average content of 85.6 ± 2.4 mg Fe/kg. The appetite, health status (clinical one) and individual weight of the chickens were controlled. On the 15th day samples of the liver from three euthanized chickens of each group were taken for histological and chemical studies. On the 35th day four more chickens of each group were subjected to the same studies. The liver samples intended for chemical analysis were frozen at -18°C and after 22 days were thawed out and tested for iron content by optical emission spectrophotometer ICP-OES 715-S. Samples of the cloacal content were taken from the chickens euthanized on the 15th and 35th day. They were also frozen and then thawed out, dried and analysed for iron content by using atomic absorption spectrophotometer equipped with graphic cuvette, model Spectra AA 800. The statistical results were processed by three different methods - parametric (Anova one-way), non-parametric (Mann-Whitney U-test) method and by using the tables of Student-Fisher. During the test period no clinical symptoms and signs of disease or mortality were found in all treated chickens; there were no pathomorphological changes in the liver of the chickens. In general, the utilisation was more favourable for the iron methionate compared to the iron sulphate. It was better expressed in the low concentration (60 ppm) - a steady growth, trend for better deposition in the liver and significantly smaller amount (up to two times) of iron in the cloacal content (beneficial for the environment). The iron deposited in the liver of the treated chickens was from 40 to 60% more than that in the control ones.


Valdazo-Gonzalez B.,The Pirbright Institute | Polihronova L.,National Diagnostic and Research Veterinary Medical Institute | Alexandrov T.,Bulgarian Food Safety Agency | Normann P.,Technical University of Denmark | And 7 more authors.
PLoS ONE | Year: 2012

Improvements to sequencing protocols and the development of computational phylogenetics have opened up opportunities to study the rapid evolution of RNA viruses in real time. In practical terms, these results can be combined with field data in order to reconstruct spatiotemporal scenarios that describe the origin and transmission pathways of viruses during an epidemic. In the case of notifiable diseases, such as foot-and-mouth disease (FMD), these analyses provide important insights into the epidemiology of field outbreaks that can support disease control programmes. This study reconstructs the origin and transmission history of the FMD outbreaks which occurred during 2011 in Burgas Province, Bulgaria, a country that had been previously FMD-free-without-vaccination since 1996. Nineteen full genome sequences (FGS) of FMD virus (FMDV) were generated and analysed, including eight representative viruses from all of the virus-positive outbreaks of the disease in the country and 11 closely-related contemporary viruses from countries in the region where FMD is endemic (Turkey and Israel). All Bulgarian sequences shared a single putative common ancestor which was closely related to the index case identified in wild boar. The closest relative from outside of Bulgaria was a FMDV collected during 2010 in Bursa (Anatolia, Turkey). Within Bulgaria, two discrete genetic clusters were detected that corresponded to two episodes of outbreaks that occurred during January and March-April 2011. The number of nucleotide substitutions that were present between, and within, these separate clusters provided evidence that undetected FMDV infection had occurred. These conclusions are supported by laboratory data that subsequently identified three additional FMDV-infected livestock premises by serosurveillance, as well as a number of antibody positive wild boar on both sides of the border with Turkish Thrace. This study highlights how FGS analysis can be used as an effective on-the-spot tool to support and help direct epidemiological investigations of field outbreaks. © 2012 Valdazo-González et al.


Sirakov I.,National Diagnostic and Research Veterinary Medical Institute | Peshev R.,National Diagnostic and Research Veterinary Medical Institute | Christova L.,Bulgarian Academy of Science
Virus Genes | Year: 2011

The aim of this study is to investigate the profile of ovine PrP gene by amino acid polymorphism at codons 136, 141, 154, and 171 for determining the genetic predisposition to the Scrapie disease for the tribal sheep and rams, with different numbers and distribution in Bulgaria. Three hundred twenty four animals originating from 41 tribal herds comprising eight breeds were included in the study. DNA was isolated from blood samples specifically amplified by PCR and sequenced. The alignments of codons 136, 141, 154, and 171 were determined. Based on the sequencing, it was established that Bulgarian breeds belong to the second and third risk groups, those with low and moderate risk of Scrapie disease. Establishment of 11 genotypes in Synthetic Population Bulgarian Milk breed reveals it to have the highest risk of the Scrapie disease; moreover, the conducting of the program will be more difficult in comparison with other investigated breeds. Evidence for the internal cross breeding is the presence of the five or six genotypes in the Copper-Red Shoumen, Replian, Karakachan, and Duben Bulgarian native breeds. © 2011 Springer Science+Business Media, LLC.


Breithaupt A.,Friedrich Loeffler Institute | Depner K.,Friedrich Loeffler Institute | Haas B.,Friedrich Loeffler Institute | Alexandrov T.,Bulgarian National Veterinary Service | And 4 more authors.
Veterinary Microbiology | Year: 2012

Foot and mouth disease (FMD) was detected in a wild boar in Southeastern Bulgaria in December 2010. The occurrence and spread of the disease in wild cloven-hoofed animals may pose an unexpected and significant threat to FMD virus (FMDV)-free areas within and outside the European Union. So far, only one well documented experimental infection with FMD in wild boar has been published. In order to obtain more epidemiologically relevant data regarding the disease in wild boar we conducted an experiment with the 2010 Bulgarian FMDV type O isolate. Two young wild boar were challenged while two domestic pigs and two additional wild boar served as contact controls. While the domestic pigs developed severe clinical signs of FMD, the wild boar showed relatively mild course of the disease. Viremia started in contact wild boar 2 days post exposure (DPE) and lasted until 6 DPE. The virus shedding lasted until 9 DPE. On 27 DPE, when the animals were slaughtered, viral RNA was detected in lymphoid tissues and oropharyngeal fluid but no virus could be isolated. Commercial ELISAs and virus neutralisation tests detected antibodies against FMDV on 8 or 6 DPE, respectively.The data of the present study will help to understand FMD in wild boar populations and can be used in models to evaluate the potential role of wild boar in FMD epidemiology. © 2012 Elsevier B.V.


Sirakov I.N.,National Diagnostic and Research Veterinary Medical Institute | Peshev R.D.,National Diagnostic and Research Veterinary Medical Institute
Iranian Journal of Veterinary Research | Year: 2012

The aim of this study was to investigate the hemagglutination properties of caprine herpesvirus-1 (CpHV-1) and their application for CpHV-1 antigen detection and evaluation of the dynamics of postinfectious/ vaccine antibody production. CpHV-1 hemagglutination activity was proved only with mouse erythrocytes, PBS and saline solutions at 4°C and 22°C. In vaccinated animals, goats and bucks with respiratory and genital clinical symptoms the antibody titers obtained by microtiter virus neutralization test (MVNT) were significantly higher (P<0.05) compared to those determined by inhibition hemagglutination test (IHA), while in aborted animals the former were lower than the latter. The diagnostic specificity (Dsp) and sensitivity (Dse) of IHA was determined by comparison of the antibody titers obtained by MVNT. Between groups comparison of MVNT versus IHA test showed significantly higher (λ<2< = 8, P<0.0047) Dse of IHA for aborted animals and vaccinated animals only. No significant differences were found for the Dsp of any of the investigated groups. IHA test is a suitable method for detecting antibody production after the onset of the disease when IgM antibodies predominate and can be successfully used as an additional method for epidemiological studies and tracing of CpHV-1 antibodies formation and exhaustion.


Marinova-Petkova A.,Regional Diagnostic Laboratory on Avian Influenza and Newcastle Disease in Birds | Marinova-Petkova A.,National Diagnostic and Research Veterinary Medical Institute | Georgiev G.,National Diagnostic and Research Veterinary Medical Institute | Seiler P.,St Jude Childrens Research Hospital | And 5 more authors.
Emerging Infectious Diseases | Year: 2012

On March 15, 2010, a highly pathogenic avian influenza virus was isolated from the carcass of a common buzzard (Buteo buteo) in Bulgaria. Phylogenetic analyses of the virus showed a close genetic relationship with influenza virus A (H5N1) clade 2.3.2.1 viruses isolated from wild birds in the Tyva Republic and Mongolia during 2009-2010. Designated A/common buzzard/Bulgaria/38WB/2010, this strain was highly pathogenic in chickens but had low pathogenicity in mice and ferrets and no molecular markers of increased pathogenicity in mammals. The establishment of clade 2.3.2.1 highly pathogenic avian influenza viruses of the H5N1 subtype in wild birds in Europe would increase the likelihood of health threats to humans and poultry in the region.


PubMed | National Diagnostic and Research Veterinary Medical Institute
Type: Journal Article | Journal: Avian diseases | Year: 2010

Newcastle disease virus (NDV) and avian influenza virus (AIV) are pathogens of major economic and social importance, and the diseases they cause are often devastating, particularly in domestic poultry. Both viruses are naturally found in a wide variety of wild birds, particularly aquatic species, where asymptomatic infection typically occurs. Wild birds are therefore considered to be a natural reservoir for both viruses. Wild birds kept in captivity are in an environment that promotes transmission of infection with both influenza and Newcastle disease viruses. This report describes a survey for the detection of antibodies against Newcastle disease and avian influenza A viruses using the hemagglutination inhibition test in samples from 88 wild birds from 38 species in four Bulgarian zoos. Samples with positive results against NDV were also tested against avian paramyxovirus type 3 (APMV-3). Real-time reverse-transcriptase PCR was also performed to detect viral RNA of NDV and AIV among 127 wild birds from 57 species from the same zoos. In 13 samples from seven avian species (ten birds from the family Phasianidae, two from the family Numidae, and one from the family Columbidae), antibodies against APMV-1 were detected. Seven birds, whose sera were APMV-1 positive, had been vaccinated. The other six birds (five Phasianidae representatives and one of the Columbidae family) had no immunization history. No antibodies against both H5 and H7 AIV and against APMV-3 were detected, and no RNA of NDV and AIV were detected.

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