Inclusion body hepatitis (IBH) outbreak associated with fowl adenovirus type 8b in broilers

The causative agent of inclusion body hepatitis (IBH) was identified as fowl adenovirus (FAdV) type 8b, a member of the Fowl adenovirus E species, based on PCR results of adenoviral polymerase and the hexon gene in an outbreak of acute mortality that affected a broiler flock of 12,000 animals. In two waves of elevated mortality rate, a total of 264 chickens were found dead. Affected birds showed ruffled feathers, depression, watery droppings and limping. The most common pathological lesions seen on necropsy were pale, swollen and friable livers. On histological examination, acute hepatitis characterized by necrosis of hepatocytes, with large basophilic intranuclear inclusion bodies, were observed. In addition, infectious bursal disease virus and infectious bronchitis virus were detected in the same flock.