Hepatitis is an inflammatory disease of the liver, and viral infection is the most common cause. There are five main types of hepatitis viruses, types A, B, C, D and E. These five types of hepatitis are of greatest concern due to the disease burden and deaths caused by the disease, as well as their potential to form outbreaks and epidemic transmission. Hepatitis B and C, in particular, cause chronic disease in hundreds of millions of people and are the most common causes of cirrhosis and cancer. The typical cause of hepatitis A and E is the consumption of contaminated food or water. Hepatitis B, C and D infections are usually the result of non-intestinal contact with contaminated body fluids. Common routes of transmission of these viruses include ingestion of contaminated blood or blood products, and use of contaminated equipment for invasive medical procedures. Hepatitis B is also transmitted from mother to infant during delivery, from family members to children, and it can also be transmitted through sexual contact. Acute infection may occur with limited or no symptoms, or with symptoms such as jaundice (yellowing of the skin and eyes), yellow urine, extreme fatigue, nausea, vomiting and abdominal pain.