Animal: Snowy Owl (Nyctea scandiaca) 8 weeks.
Diagnoses: Liver: Hepatitis, necrotizing, multifocal, severe, acute; mild hepatomegaly Spleen: Splenitis, necrotizing, multifocal to coalescing severe, acute; moderate splenomegaly Intestine: Serositis, necrotizing, severe, acute, multifocal to coalescing
Description: The liver and spleen had multifocal white to yellow partly coalescing foci of necrosis with the spleen most severely affected. Microscopically, multiple nuclei of hepatocytes peripheral to the necrotic foci contained intranuclear, eosinophilic inclusion bodies. Necrotic foci in the intestine were often transmural extending to and affecting the serosa. The lung also had a necrotizing bronchitis and peribronchitis.
Comments: Herpesviral infections of owls are caused by the Strigid Herpesvirus 1 (SHV-1) which can affect several species of free-ranging and captive owl species. The disease is usually fatal and like in the present case can affect multiple birds in an aviary. Here, two nest siblings suddenly died after one day of poor general condition. Although the macroscopic lesions in the intestine appeared like pyogranulomas, histopathology revealed large necrotic foci without evidence of bacterial, fungal or parasitic involvement. Subsequent microbiological culturing failed to identify any pathogens from samples of the liver, blood and lung of both deceased owls.
Author: Philipp Olias, Department of Veterinary Pathology, Freie Universität Berlin, Germany