Viral Hepatitis.

Since 2012, 2 viral causes of hepatitis have been identified in horses. Much remains to be discovered about their transmission, risk factors for clinical disease, diagnosis, and treatment approaches. Equine parvovirus-hepatitis has been identified as the cause of acute hepatic necrosis, previously known as Theiler's disease. Equine hepacivirus is recognized as a cause of chronic fibrosing hepatitis. Diagnosis relies on ruling out other causes of hepatitis and documenting infection by serum or liver polymerase chain reaction. There is no direct antiviral for either condition and treatments are symptomatic or aimed at ameliorating effects of liver failure and encephalopathy if present.