First detection of FAdV serotype 8b associated with Inclusion Body Hepatitis in broiler flocks in the southern part of Iraq during, 2022-2023

Field observations reported many outbreaks of IBH infection in poultry flocks in different regions of Basra province leading to high economic losses, and the diagnosis of the disease is based on clinical signs and gross pathological lesions. Little information on FAdV recently circulating in the southern part of Iraq; thus, partial sequencing of hexon gene of four FAdV has been detected in the present study during the period between mid-2022 to the beginning of 2023 from various FAdV outbreaks in commercial broiler farms in southern parts of Iraq. The results showed the four Iraqi field strains of FAdV were closely related and shared a high identity of 100% to each other and to previous Iraqi strains from the northern part of Iraq. Phylogenetic analysis indicated that the four viruses obtained from this study and two additional viruses from Ninawa province are classified as serotype 8b of FAdV group E, as a predominant serotype related to inclusion body hepatitis, and clustered along with the same 8b serotype of FAdV circulating in Indonesia, Turkey, and Israel. The results provided useful genetic information on FAdV that recently reemerged in Iraq in 2022 and 2023 and might assist in the production of a local vaccine for FAdV serotype 8b.