Phylogenetic analysis and pathological characterization of fowl adenovirus isolated during inclusion body hepatitis outbreak in Tubas, Palestine

Fowl adenoviruses (FAdVs) associated with inclusion body hepatitis (IBH) was identified in commercial broiler chickens in Palestine. Investigated birds showed primary clinical signs and lesions of IBH including growth retardation, congested and enlarged liver with necrosis, petechial hemorrhage and basophilic intra-nuclear inclusion bodies. The mortality rate was from 15.00%. The FAdV was detected and sequenced in the liver samples of infected chicken by polymerase chain reaction using hexon gene-specific primers. Phylogenetic analysis revealed that FAdVs belong to FAdV-D serotype 10, clustered within the European highly pathogenic isolates. The highest nucleotide sequence similarity was 99.48% with highly pathogenic FAdV-D serotype 10 detected from infected chicken in Poland (GenBank: LN907532.1) and FAdV-D from infected chicken in Sweden (GenBank: HE961828.1). The lowest similarity was 93.46% with Canadian FAdV-D (GenBank: EF685576.1). In conclusion, this is the first report describing the presence of IBH revealing that the causative virus is closely similar to the highly pathogenic FAdV-D serotype 10 of IBH in broiler chickens in Palestine. (c) 2021 Urmia University. All rights reserved.