Systematic Veterinary Virology

LESIONS

• DHV I infection
• The liver is enlarged and covered with hemorrhagic foci up to 1 cm in diameter.
• The spleen may be enlarged and mottled.
• Kidneys may be swollen with congested blood vessels.
• Microscopic changes in the liver are characterised by extensive hepatocyte necrosis and bile duct hyperplasia, together with varying degrees of inflammatory cell response and haemorrhage.
• DHV II infection
• Lesions include multiple haemorrhages, both punctate and confluent bands in the liver, swollen pale kidneys with congested blood vessels, and enlarged spleens.
• The alimentary tract is often empty although the small intestine may contain mucus, and haemorrhagic areas are occasionally seen.
• Petechial haemorrhages are also occasionally seen on the heart.
• Histologically, changes in the liver are similar to those seen in DHV type I infections.
• DHV III infection
• The gross pathology is also similar to type I infection. The liver surface is pale and mottled with many red bands and some petechial haemorrhages.
• The spleen is paler, but not noticeably enlarged, and the kidneys may show patchy congestion.