Isolation of viruses from clinical outbreaks of inclusion body hepatitis

Sixteen outbreaks of inclusion body hepatitis (IBH) in fowls were investigated. Most cases occurred in broilers, and birds 4-9 weeks old were affected. Mortality occurred over a period of 3-5 days, and reached 5% in some cases. The main pathological finding was a diffuse and generalised hepatitis, with eosinophilic intranuclear inclusions in the hepatocytes. From these outbreaks 46 adenoviruses and 6 reoviruses were isolated. The adenoviruses were classified into 5 serological types. Two outbreaks of IBH in pigeons were also examined. Herpesviruses and adenoviruses were isolated from both cases. It was possible to assign one adenovirus isolate to a known fowl adenovirus serotype.