On October 2012, an onset of high acute mortality in a flock of 2-day old broiler chickens was reported to Veterinary Clinic, Faculty of Veterinary Medicine, Razi University, Kermanshah, Iran. During the disease outbreak, the farm was visited regularly. The farm was located in northwest of Kermanshah province. Totally, 35,000 broiler chickens were kept in 5 windowless houses (7000 birds per house). Wood shavings were used as litter. All houses were equipped with central heaters, pad cooling systems and ventilators to provide the optimum environmental conditions for the broiler chickens. The birds were fed with a commercial corn-soybean meal starter diet. Feed and water were provided ad libitum. The lighting program was 23 hr light and 1 hr dark. All chickens of the farm were vaccinated against infectious bronchitis virus at the time of arrival to the farm. 
At farm visits, clinical signs and daily mortality were recorded. Clinically, the birds showed lethargy, ruffled feathers, and inappetence. Huddling and smothering were the major observed clinical signs. Mortality of the disease started with 300 chicks per 24 hr on 2nd day of age, peaked at 410 on 5th day and then gradually declined to normal at the age of 21 days. During the course of disease, total mortality reached about 14%.
On daily visits, a complete necropsy was carried out on at least five newly dead or euthanized sick birds of each house. Tissue samples of liver, kidneys and heart were fixed in 10% buffered formalin. They were processed according to routine procedures and stained with hematoxylin and eosin (H & E) for histopathology. 
Due to some restrictions, we could not follow up the case with virus isolation or molecular methods to identify the exact etiological agent of the disease. Therefore, based on the acute high mortality, age of the broilers, and gross and microscopic lesions (especially intra-nuclear inclusion bodies), the condition was diagnosed as adenovirus-like inclusion body hepatitis. At necropsy the livers were the primary organ affected which were enlarged, pale yellow with necrotic foci and multiple petechial hemorrhages (Fig. 1).
Kidneys appeared swollen and pale (Fig. 2). On histopathological examinations, significant lesions were seen in the liver. Focal hepatitis with infiltration of mononuclear inflammatory cells was noted. Large eosinophilic intra-nuclear inclusion bodies were seen in hepatocytes (Fig. 3). Kidneys showed severe hyperemia, tubular epithelial cells degeneration, intra-tubular cellular cast formation, and mild interstitial nephritis. Mild focal myocarditis, with degenerated muscle fibers was seen in the heart sections.