title: Differentiation of infectious bursal disease viruses isolated in Croatia.
abstract: Infectious bursal disease viruses (IBDVs) in 26 IBDV-positive bursa samples collected in Croatia during the period 1996-2000 and in two commercially available vaccines were differentiated by the presence or absence of the CfoI, SacI, SspI, StuI, and TaqI restriction sites in the 422-bp fragment of segment A of the VP2 gene (nt 732-1153). The fragments from 14 (54%) field isolates were TaqI+ StuI+ SspI+ and SacI- CfoI-, indicating their very virulent (vv) character. The presence of CfoI restriction site in 10 (38%) field isolates is uncommon for vvIBDV strains. It was detected in only the 88180 vvIBDV strain. Nevertheless, these isolates can be classified as vv strains according to TaqI+ StuI+ SspI+ SacI- restrictions. Two SacI+ StuI+ CfoI+ TaqI- SspI- field isolates (8%) could be classified as non-vvIBDVs. The StuI+ restriction is common to vvIBDV strains. However, the StuI recognition sequence is present in the F52/70 classic European and 002-73 attenuated strains as well. The SacI+ CfoI+ StuI- SspI- restrictions and the lack of the TaqI restriction at nt position 832 show that the IBDV in GUMBOKAL IM-SPF vaccine corresponds to the attenuated and/or vaccine strains. The TaqI restriction at nt position 875 suggests that the IBDV in GUMBOKAL SPF vaccine could belong to the mild strains.
authors.affiliation: Department of Poultry Pathology, Faculty of Veterinary Medicine, University of Zagreb, Zagreb, Croatia.
authors.forename: I
authors.initials: I
authors.lastname: Lojkić
authors.forename: Z
authors.initials: Z
authors.lastname: Bidin
authors.forename: B
authors.initials: B
authors.lastname: Pokrić
mesh_terms: D000818:Animals; D018175:Birnaviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology*; D002060:Bursa of Fabricius / Q000821:virology; D002645:Chickens / Q000821:virology*; D017523:Croatia / Q000453:epidemiology; D005814:Genes, Viral; D007243:Infectious bursal disease virus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D011201:Poultry Diseases / Q000453:epidemiology / Q000821:virology*; D015183:Restriction Mapping; D014765:Viral Vaccines / Q000235:genetics; D014774:Virulence
chemical_list: D014765:Viral Vaccines