Concurrent Infection of Infectious Bronchitis (IB) and Sub-Clinical Infectious Bursal Disease (IBD) in an Organised Poultry Farm -

Four carcasses of 4-5 days old chicks were submitted for post-mortem examination to the Department of Veterinary Pathology, College of Veterinary and Animal Sciences, Mannuthy, Thrissur. The owner reported 60% mortality in the flock. Grossly, chalky deposits could be observed on the pericardium, liver and in mesonephric tubules of the kidneys. Histopathology revealed focal pneumonia and congestion, uric acid pericarditis, fatty degeneration with capsular thickening in liver, degeneration and uric acid crystals in the renal tubules. Spleen and bursa revealed lymphoid depletion. Reverse-transcriptase polymerase chain reaction carried out with the pooled tissue samples gave positive results for both IB and IBD. The nephrogenic form of IB would have resulted in nephrosis, uric acid pericarditis and perihepatitis. Though the bursa did not reveal any striking gross pathology, the histopathological changes in the bursa and positive PCR results for IBD suggest a sub-clinical infection.