Detection and phylogeny of fowl adenovirus associated with hydropericardium hepatitis syndrome in broilers

Hydropericardium hepatitis syndrome (HHS) in broilers is an emerging threat, causing huge economic loss to poultry industry every year. Fowl adenoviruses (FAdVs) associated with HHS could disturb growth, viability and immunity in commercial broilers. The main aim of the present study was to detect and characterize FAdVs. Liver tissues were collected from poultry flocks showing clinical signs of HHS and investigated using PCR assay for FAdVs. The FAdVs were detected in 8 samples collected from different flocks. Positive PCR amplicons were sequenced to genetically identify the FAdVs. Phylogenetic analysis revealed two distinct clusters among FAdVs. One cluster containing 3 strains belonged to the FAdV- C species and serotyped as FAdV-4 and showed close proximity at the nucleotide level. The other cluster containing three strains belonged to the FAdV-D species and serotyped as FAdV-11. Furthermore, the sequencing analysis of detected field strains revealed the high similarity and close clustering with FAdV-4 and FAdV-11 strains isolated from neighboring countries, suggesting geographic and temporal relationships among these strains. This evidence emphasizes the need of further detailed and more systemic approaches to evaluate FAdVs diffusion and characterization to design effective control strategies.