Genotyping of Fowl Adenoviruses Detected from Inclusion Body Hepatitis in Iran, 2020

Inclusion body hepatitis (IBH) is one of the most critical diseases in many countries with intensive poultry industries. In Iran, the etiological agent of IBH (fowl adenovirus) has been confirmed. This study aimed to determine the molecular detection and identification of fowl adenovirus involving IBH in chicken flocks during the year of 2020 in Iran.

For this purpose 150 liver tissue samples from 15 broilers flocks suspected in IBH infection were collected from Mazandaran province and were subjected to PCR analysis and histopathological examination. Polymerase chain reaction (PCR) and sequence analysis of the L1 hexon gene were utilized to detect and determine Fowl adenovirus (FAdV) genotypes in broiler farms. Histopathological sections were prepared and examined.

FAdV infection was confirmed by PCR in 14 out of 15 broiler flocks. Based on sequencing analysis of the hexon gene, they were genetically related to FAdV-11, a member of the fowl adenovirus D species. Homology among the isolates, Iranian isolates, and other counties was 94.44% - 97.11%. Histological examination revealed necrotizing hepatitis with basophilic and eosinophilic intranuclear inclusion bodies in the hepatocytes.

The results confirm previous reports about high prevalence of FAdV infection in broiler flocks and show continuos circulation of genotype 11 in Iranian broiler flocks.