The most common hepatitis viruses are types A, B, and C. Reference to the hepatitis viruses often occurs in an abbreviated form (for example, HAV, HBV, HCV represent hepatitis viruses A, B, and C, respectively.) The focus of this article is on these viruses that cause the majority of human viral hepatitis. Viruses that primarily attack the liver are called hepatitis viruses. 2  There are several types of hepatitis viruses including types A, B, C, D, E, and possibly G. Types A, B, and C are the most common. 3  All hepatitis viruses can cause acute hepatitis. 4  Viral hepatitis types B and C can cause chronic hepatitis.