title: Very virulent infectious bursal disease virus in southeastern Europe.
abstract: Clinical outbreaks of severe acute infectious burial disease (IBD) were recorded since the mid- and late 1990s in several countries in the southeastern part of Europe. Epidemiologic data showed that both infectious bursal disease virus (IBDV)-vaccinated and IBDV-nonvaccinated chickens were affected with acute IBD and mortality up to 50% independent of the IBDV vaccination status of the appropriate parent flocks. For investigation of the causative agent of acute IBD, the variable region of VP2 was amplified, cloned, and sequenced. Nucleotide sequence analysis of polymerase chain reaction fragments showed several silent nucleotide exchanges in comparison with the sequence of the very virulent (vv) IBDV strain UK661. Also, restriction enzyme cleavage sites proposed specific for vvIBDV were present in all investigated strains. On the basis of clinical signs in affected flocks, recorded epidemiologic data, and sequence analysis, it is very likely the IBD-causing strains were of the vv phenotype.
authors.affiliation: Veterinary Faculty, University of Ljubljana, Gerbiceva 60, 1000 Ljubljana, Slovenia.
authors.forename: Olga
authors.initials: O
authors.lastname: Zorman-Rojs
authors.forename: Darja
authors.initials: D
authors.lastname: Barlic-Maganja
authors.forename: Darko
authors.initials: D
authors.lastname: Mitevski
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lübke
authors.forename: Egbert
authors.initials: E
authors.lastname: Mundt
mesh_terms: D000375:Aging; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018175:Birnaviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology*; D002645:Chickens / Q000821:virology*; D004196:Disease Outbreaks / Q000662:veterinary; D005060:Europe / Q000453:epidemiology; D007243:Infectious bursal disease virus / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity*; D008969:Molecular Sequence Data; D010641:Phenotype; D011201:Poultry Diseases / Q000453:epidemiology / Q000821:virology*; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014765:Viral Vaccines / Q000276:immunology; D014774:Virulence
chemical_list: D014765:Viral Vaccines