Application of the fluorescent antibody technique to the diagnosis of avian encephalomyelitis.

A direct fluorescent antibody test was applied to the diagnosis of avian encephalomyeltis in experimental chicks and in chicks from three natural outbreaks of the disease. Intracerebrally inoculated chicks exhibited maximum fluorescence in brain tissue during the early clinical stages of the disease and similar observations were made on natural cases. Best fluorescence was obtained with frozen sections of cerebellum and pancreas from chicks approximately three weeks of age, but after four weeks of age it was not possible to diagnose the naturally-occurring (field) disease by this method. In these cases a diagnosis of avian encephalomyelitis was confirmed by the application of the fluorescent technique to the brains of either (a) chicks which had hatched from eggs inoculated with brain homogenates from the field cases or (b) hatched chicks which had been inoculated with the homogenates by the intracerebral route.