An inflammation of the liver caused by a variety of agents including viral infection (hepatitis A virus, hepatitis B virus, hepatitis C virus and delta agents), bacterial invasion and physical and chemical agents. Symptoms are fever, nausea, vomiting, fatigue, malaise, muscle and joint pain, headache, photophobia, cough followed by jaundice and an enlarged liver. Hepatitis A and delta agent hepatitis are spread primarily from person to person via the fecal-oral route, but may occur by contact with water or food contaminated by the virus. Hepatitis B and C are spread by blood and serum-derived fluids and by direct contact with body fluids.