Characterization of fowl adenoviruses associated with hydropericardium syndrome and inclusion body hepatitis in broiler chickens.

The present study was carried out for detection and molecular characterization of fowl adenoviruses (FAdVs) associated with hydropericardium syndrome or inclusion body hepatitis in commercial broiler chickens. The FAdVs were detected in liver samples from 33 commercial broiler chicken flocks by polymerase chain reaction (PCR) using hexon gene specific primers. The restriction enzyme analysis using StyI, BsiWI, MluI, AspI, BglI and ScaI enzymes of all the 33 FAdV-positive samples revealed FAdV-4 in 10 samples, FAdV-8 in five samples, FAdV-2 and FAdV-12 in two samples each, and FAdV-5 and FAdV-6 in one sample each. Twelve samples revealed the digestion pattern for more than one serotypes with FAdV-8 and FAdV-5, FAdV-8 and FAdV-7, FAdV-8 and FAdV-6, FAdV-8 and FAdV-12 being the predominant combinations indicating mixed infection. The serotypes FAdV-2 and FAdV-5 have not been detected previously in the country. The purified PCR products of FAdVs of four samples (HR 1, HR 2, HR 3 and HR 4) were cloned and sequenced. Phylogenetic analysis revealed that FAdVs of all four samples clustered in separate groups consistent with the REA pattern. In conclusion, this study reveals the presence of FAdV-2, FAdV-4, FAdV-5, FAdV-6, FAdV-7, FAdV-8 and FAdV-12 in broiler chickens affected with hydropericardium syndrome or inclusion body hepatitis in India.