Submitted to: Avian Diseases
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/10/1998
Publication Date: N/A
Citation: Interpretive Summary: Infectious bursal disease virus (IBDV) causes an economically important disease of commercial poultry that results in suppression of the chicken immune system. The virus continues to circulate among commercial poultry flocks. Consequently, three IBDV isolates recently obtained in the southeastern U.S. were analyzed for genetic differences. One of the IBDV isolates was very similar to viruses previously identified in Delaware. A second virus was very similar to IBDV isolates considered as emerging recently in the U.S., while the third isolate was most similar to IBDV reference strains. One protein component of the outer virus structure contains specific regions that may be very different from one isolate to the next. These hypervariable regions were very different in each of the recently obtained IBDV isolates. Consequently, IBDV continues to evolve and new viruses continue to emerge in commercial poultry.
Technical Abstract: Three infectious bursal disease field viruses, isolated in the late eighties from the southeastern United States, were characterized both antigenically and genotypically. The viruses were isolated the same time as variants in the Delmarva peninsula. A panel of monoclonal antibodies (MAbs) was utilized in an antigen capture enzyme-linked immunosorbent assay y(ELISA) for antigenic characterization. The ELISA data indicated that U28 and the Delaware variants are antigenically related. The 3212 and the GLS variants were more closely related to each other antigenically than to other viruses analyzed. The MISS isolate reacted with MAbs that were specific for both classic and variant strains of IBDV. Reverse- transcription-polymerase chain reaction (RT-PCR) was used to amplify nucleotide sequences from the genome coding for the variable region of VP2 from infectious bursal disease virus (IBDV) field isolates, U28, 3212, and MISS. The amplified products were sequenced and analysis of the nucleotid and deduced amino acid sequences was completed. Phylogenetic analysis of the deduced amino acid sequences revealed that U28 was most similar (98.3%) to the IBDV Delaware variants and that 3212 was most similar (97.1%) to the GLS variant. The MISS isolate was most similar (97.4%) to the reference 52/70 strain.