An unusual case of hemorrhagic bursa in a pullet flock associated with a genogroup 2 infectious bursal disease virus

Avian Pathol. 2021 Apr 7:1-20. doi: 10.1080/03079457.2021.1912287. Online ahead of print.ABSTRACTSUMMARYAn unusual case of Infectious Bursal Disease (IBD) was observed in eight-week-old commercial caged pullets. This flock (House 1) exhibited a one-day spike in mortality. On gross necropsy examination, enlarged, diffusely hemorrhagic bursas were observed. This lesion has been frequently described in cases of very virulent Infectious Bursal Disease Virus (vvIBDV). A five-week-old caged pullet flock (House 2) in an adjacent building did not display hemorrhagic bursa lesions. Microscopic examination of bursas from the eight-week-old pullets in House 1 showed marked diffuse hemorrhages and extensive lymphoid necrosis. Histopathology of bursas from the 5-week-old pullets in House 2 showed severe, diffuse lymphoid depletion without hemorrhages. IBD ELISA results from birds in House 1 at nine weeks had a GMT of 6395 and birds in House 2 had a GMT of 82 in the same timeframe. Diagnostic testing for avian influenza, Mycoplasma gallisepticum, Mycoplasma synoviae, virulent Newcastle disease virus, infectious bronchitis virus, infectious laryngotracheitis, chicken anemia virus (CAV) and fowl pox were negative. The predicted amino acid sequence of the hypervariable region of VP2 indicated the IBDV observed in both flocks (1/chicken/USA/1300OH/19 from house 1 and 1/chicken/USA/1301OH/19 from house 2) was identical and was not a vvIBDV. Their sequences were similar to a Genogroup 2 IBDV fro...
Source: Avian Pathology - Category: Pathology Authors: Source Type: research