Abstract

Hydropericardium syndrome (HPS) is a viral disease of poultry, which is common in hot and humid season during summer in Pakistan. Fowl adenovirus serotype 4 (FAdV-4) classified into the species Fowl adenovirus C and the genus Aviadenovirus, which were identified as the causative agent of the disease during field outbreaks.  The virus was obtained from suspected broiler birds showing typical signs and postmortem lesions that is ascites, hydropericardium, multifocal hepatic necrosis and hepatitis. The virions were partially purified from the livers of infected birds, by sucrose density gradient ultracentrifugation. A variable part of the hexon gene (L1 and part of P1, 730 bp) was amplified by polymerase chain reaction (PCR) and its nucleotide sequence was determined. During nucleotide sequence analysis, the viruses were identified as FAdV- 4. The presence of FAdV-4 was also supported by scanning electron microscopy. Phylogenetic analysis of the partial hexon gene of the viruses determined their close relation with previously sequenced FAdV-4 isolates from India.

Key words: Fowl adenovirus serotype 4 (FAdV-4), hydro-pericardium syndrome, hexon, electron microscopy, phylogenetic analysis, taxonomy.