Abstract
Local viral isolates of hydropericardium hepatitis syndrome were isolated and identified by viral propagation in yolk sac of chicken embryo eggs. All isolates were diagnosed as adenovirus serotype 4 by serum neutralization test using specific refererence antisera against serotype 4 adenovirus, and confirmation of diagnosis was done by Electron–microscopic observation, Icosahedral adenovirus –like particles 85-90 nm in diameter were observed in negative staining of all virus isolates.