Viral genotyping of infectious bursal disease viruses isolated from the 2002 acute outbreak in Spain and comparison with previous isolates.
An infectious bursal disease (IBD) outbreak occurred in the east region of Spain in the spring of 2002 and rapidly spread thorough the whole country, although proper vaccination programs were applied. In this report, 33 infectious bursal disease viruses (IBDVs) isolated from this outbreak were characterized by nucleotide sequencing of the VP2 gene hypervariable region and were compared with reference IBD strains and the 1990s Spanish IBDVs in order to determine possible emergence of IBDV isolates with modified antigenic or virulent properties. Moreover, histopathologic and immunohistochemical studies of those cases where bursal tissues were available were carried out. Of the 33 isolates, 23 were identified as very virulent IBDVs (vvIBDVs), whereas the other 10 isolates were classified as attenuated or intermediate virulence classical strains and could possibly be IBDV live vaccine strains used in the immunization of these chickens. Results of this study indicate that wIBDV isolates from the 2002 Spanish outbreak are closely related with those from the 1990s outbreak. However, acute IBD cases have not been reported in Spain during these 10 yr. Genetic, management, and environmental factors likely related with IBD reemergence in Spain are discussed. Moreover, our results indicate that good correlation exists between the IBDV subtype present in the field and the degree of lesions in bursa tissue, as well as the immunohistochemistry staining.
Dolz
R
R
Centre de Recerca en Sanitat Animal, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
Majó
N
N
Ordóñez
G
G
Porta
R
R
D000595:Amino Acid Sequence; D000818:Animals; D018175:Birnaviridae Infections / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary* / Q000821:virology*; D002645:Chickens; D004196:Disease Outbreaks / Q000706:statistics & numerical data / Q000662:veterinary*; D005838:Genotype; D007150:Immunohistochemistry; D007243:Infectious bursal disease virus / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010802:Phylogeny; D011201:Poultry Diseases / Q000453:epidemiology* / Q000473:pathology / Q000821:virology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013030:Spain / Q000453:epidemiology; D015678:Viral Structural Proteins / Q000235:genetics
C082513:VP2 protein, infectious bursal disease virus; D015678:Viral Structural Proteins