The most common presentation is an explosive mortality event with death due to peracute systemic haemorrhagic disease. In these cases, usually there are no external lesions. Skin vesicles have been reported with ATV infection in tiger salamanders( Ambystoma tigrinum ). A chronic ranavirus disease, characterised by skin ulceration and necrosis of the distal limbs, has been reported from the United Kingdom.
In haematoxylin and eosin stained sections of skin, epithelial hyperplasia with disruption of the normal stratified architecture of the epidermis and often with necrosis of the deeper epithelial layers has been reported. Multiple foci of necrosis can be found in tissues, but these are rare in cases of the skin ulcerative form of disease. These necrotic foci are most obvious in the renal and splenic haematopoietic tissue and in the liver. Intracytoplasmic virus inclusions have been reported in a variety of tissues, most obviously in hepatocytes.
Infection has been demonstrated in all major tissues except for striated (skeletal) muscle, smooth muscle and cardiac muscle. However, virus can be isolated from skeletal muscle, probably from blood in tissues.