outbreak of inclusion body hepatitis associated with high mortality in broiler chickens: clinical and histopathological studies

Nowadays, adenovirus infections such as inclusion body hepatitis (ibh), pose significant challenges for commercial and backyard chicken farming in iran. in this study, the disease outbreak of ibh in a broiler chicken farm has been investigated through clinical and histopathological examinations. a 42-day-old broiler flock with 30,000 birds recently faced a severe outbreak of a devastating disease with high mortality in the fars province of iran. the farmer had not used the ibd vaccine for over 15 years. the mortality rate was 53% (16,000 birds) during the two-weeks. several affected and dead chickens were necropsied and samples of liver and kidneys were fixed in 10% neutral buffered formalin for microscopic examination. clinically, the affected broiler chickens showed depression, loss of appetite, emaciation, and greenish diarrhea. necropsy showed some degrees of jaundice, and enlargement associated with paleness of kidneys, and the livers were enlarged associated with foci of hemorrhages and whitish areas of degeneration and necrosis. histopathologic examination of livers revealed hemorrhage, necrosis, vacuolar degeneration (fatty change), and presence of basophilic intranuclear inclusion bodies in the hepatocytes that filled the entire nuclei. in the kidneys, degeneration and necrosis of proximal tubules as acute tubular necrosis was diagnosed. due to the histopathological results, the disease was diagnosed as ibh. to prevent or mitigate such risks, strict biosecurity measures, a healthy feed ration, and a good vaccination program are essential for broiler chickens.