Rapid diagnosis of infectious bursal disease infection by immunofluorescence on clinical material.

Direct immunofluorescence on impression smears of bursa of Fabricius and direct electron microscopic examination of bursal specimens were compared with virus isolation in chick embryo fibroblasts (CEF) and embryonated eggs for the diagnosis of infectious bursal disease (IBD). In chicks experimentally infected with a virulent strain of virus, immunofluorescence was a more sensitive method of demonstrating infection than direct electron microscopy or virus isolation. In chicks experimentally infected with an avirulent strain of virus, immunofluorescence and virus isolation in CEF were equally sensitive methods of demonstrating infection and more sensitive than direct electron microscopy or virus isolation in embryonated eggs. In two field surveys immunofluorescence was, overall, more sensitive than virus isolation and direct electron microscopy and gave a good correlation with histopathological diagnosis of IBD.