The most common causes of acute viral hepatitis are, collectively, the five identified viral hepatitides: A (HAV), B (HBV), C (HCV), D (HDV or delta-virus), and E (HEV).
HAV and HBV have been well characterized, and vaccines have been developed to prevent their transmission.
A vaccine is not available for HCV, but the number of reported new cases is decreasing most likely due to better screening of transfused blood products and the adoption of universal precautions.
The diagnosis of acute hepatitis is made on the basis of classic signs (jaundice, fever, arthralgia) and symptoms (may be nonspecific such as fatigue or poor appetite) together with laboratory studies. Many infections are subclinical.
Incubation periods can be several weeks to even months, and patients may undergo surgery without awareness of illness. For this reason, viral hepatitis should be part of the differential diagnosis when there is any evidence of postoperative liver injury.