Hepatitis B is a contagious liver disease caused by the hepatitis B virus (HBV), one of three viral agents that cause inflammation of the liver known as hepatitis or diffuse hepatocellular inflammatory disease. Hepatitis B is characterized by fever, nausea, vomiting, and yellow discoloration of the skin, eyes and mucous membranes (jaundice). In its most serious form, if left untreated, hepatitis B can become a chronic infection leading to chronic liver disease and potentially increasing the risk of developing liver cancer. The hepatitis B virus can be passed from mother to unborn child, and is highly contagious through bodily fluids such as blood, semen and possibly saliva. It is often spread from person to person through intravenous drug use or sexual contact.