Hepatitis A is an acute liver infection caused by a virus. Infections occur from ingesting food or water contaminated by infected feces and it can be easily passed from person to person. Most young children do not have symptoms or have an unrecognized infection. Most adults with hepatitis A have symptoms, including fatigue, abdominal pain, nausea and jaundice. Hepatitis A is often associated with travel to places where it is more common. A vaccine is available to prevent the disease.