GENOMIC VARIATION IN HEXON GENE OF INCLUSION BODY HEPATITIS VIRUS IN BROILER, IRAQ

Adenovirus is responsible for inclusion body hepatitis. Chicken adenovirus (FAdV), a member of the Adenoviridae family, is the virus that causes chicken inclusion body hepatitis (IBH). The first report of the disease in Iraq was in 1979, yet the virus is not characterized. During the period from September 2021 to May 2022, we tracked disease outbreaks in 110 broiler farms in the central of Southwestern, and Southern parts of Iraq. Precisely, these areas were Al-Daghara, Al-Amarah, Baghdad, and Al-Diwaniyah. Birds affected were with clinical signs including lethargy, huddling, ruffled feathers, a lack of appetite, and yellowish mucoid droppings. The carcasses showed pale skin or icteric, the liver was mottled and enlarged, and the kidney was enlarged with distended tubules in the postmortem examination.The histological examination showed large intranuclear inclusion bodies, congestion, and liver sinusoidal degeneration. There was a higher incidence of necrotizing pancreatitis. The virus was detected using reverse transcription-PCR (RT-PCR) of the hexon genes (RT-PCR). Using next-generation sequencing, the amplified fragments were confirmed to be authentic. According to the findings of the study, broiler chickens of all breeding ages were susceptible to infection and the IBH was widespread in the studied areas during that time period.