Characterisation of fowl adenovirus (FAdV-8b) strain concerning the geographic analysis and pathological lesions associated with inclusion body hepatitis in broiler flocks in Turkey

Abstract

IntroductionFowl adenovirus can cause important diseases in chickens such as inclusion body hepatitis, hepatitis hydropericardium syndrome, and gizzard erosion and ulceration. Inclusion body hepatitis has been regularly reported from many countries. This is the first case report from Turkey, describing an outbreak of inclusion body hepatitis in broiler farms due to fowl adenovirus-8b (FAdV-8b).Material and MethodsBroiler flocks with mortality about 10% were visited in Turkey, and necropsy was performed on dead birds. Samples were subjected to PCR assay to detect FAdV and other viral pathogens. After sequencing, phylogenetic analysis was performed and the nucleotide sequences of hexon genes were compared with the FAdV sequences data available in GenBank.ResultsClinical signs such as anorexia, depression, ruffled feathers, huddling, and greenish diarrhoea were observed. Mortality started at the 8th day of age and ranged from 10% to 14%. Necropsy showed severe hepatitis, jaundice, and pancreatitis. The main necropsy findings included a pale, enlarged, haemorrhagic, and friable liver along with swollen and haemorrhagic kidneys and spleen. PCR and sequence analysis revealed the presence of fowl adenovirus serotype 8b (FAdV-E).ConclusionThis is the first report on characterisation and the pathological lesions associated with FAdV in broilers in Turkey. Our findings suggest that FAdV strains could be an emerging pathogen in Turkish broilers and could actively contribute to hepatitis and immunosuppression.

Historical Investigation of Fowl Adenovirus Outbreaks in South Korea from 2007 to 2021: A Comprehensive Review

“…Since the Iranian and Indonesian FAdV-8b strains were isolated fairly recently, the possibility of them being recent derivatives or recombinants of the SD1356 strain cannot be ruled out. The rapid distribution of IBH-associated FAdV-8b strains in the past few years is becoming a worldwide phenomenon, including Asian and non-Asian countries [79,84,93,94].…”

The first complete genome sequence and pathogenicity characterization of fowl adenovirus serotype 2 with inclusion body hepatitis and hydropericardium in China

“…In recent years, FAdV-4 has been proven to have immunosuppressive potential, which caused structural and functional damage of immune organs via apoptosis along with induction of severe inflammatory responses ( 45 – 47 ). Other serotypes of FAdVs have also been reported to cause immune system damage in chickens, such as FAdV-8b, and FAdV-11 ( 48 – 50 ). In our study, not only the spleen indexes of challenge groups were significantly higher than that of the control groups, but also massive necrosis of lymphocyte was observed in spleen of infected 3-days-old chickens.…”

First Evidence of Fowl Adenovirus Induced Inclusion Body Hepatitis in Chicken in Bangladesh

“…Polymerase chain reaction (PCR) with primer sequences based on the hexon gene or the 52 K gene is useful for virus identifcation [23][24][25][26]. Besides, PCR together with DNA sequencing and/or restriction enzyme analysis has been used for FAdVs typing [27]. Real-time PCR and subsequent high-resolution melting (HRM) curve analysis of three regions of the hexon gene were also reported and assessed for their potential in diferentiating 12 FAdVs reference serotypes [28].…”