FULMINANT HEPATITIS INDUCED BY HERPESVIRUS IN A COMMON WOMBAT (VOMBATUS URSINUS)

A male 2-year-old Common wombat (Vombatus ursinus) suddenly began showing symptoms of inappetence, weight loss, polyuria and polydipsia. Blood collection revealed elevated liver enzymes, glucose, fructosamine and CK values, low WBC count and elevated serum molybdenum and copper values. Abdominal ultrasound showed hyperechoic and dissociated hepatic tissue, as well as dilated intestinal loops. Despite supportive therapy, the animal died three days after the onset of clinical signs. On necropsy, edematous lungs, cardiac muscle pale and friable, dilated and gas-filled intestinal loops, pale kidneys, splenomegaly and hepatomegaly, with extremely fragile hepatic tissue, were found. Histopathology revealed necrotizing, non-suppurative myocarditis with areas of myocardial fibrosis, type II crescentic glomerulonephritis and focal hepatic necrosis with mononuclear infiltration and complete structural dissociation. Liver sections showed scattered intranuclear viral inclusions within the necrotic areas, and anti-herpesvirus immunoperoxidase stain evidenced strong nuclear staining. Within these zones, residual hepatocytes had enlarged "ground glass" nuclei with margination of chromatin. These findings could be consistent with fulminant hepatic necrosis due to herpesvirus. Transmission electron microscopy revealed hexagonal 100-110 nm in diameter capsids within distorted nuclei of hepatocytes, in a central zone immediately surrounded by a thick band of dense chromatin or in a mixture of electron-dense material, marginated against the nuclear membrane, but not in the extracellular space. A nested Pan-herpesvirus PCR showed a positive fragment that will be sequenced to confirm the result. To the best of our knowledge, this is the first report of a herpesvirus induced hepatitis in the Common wombat outside his native area.