Viral hepatitisEdit
The most common causes of viral hepatitis are the five unrelated hepatotropic viruses hepatitis A, hepatitis B, hepatitis C,hepatitis D (which requires hepatitis B to cause disease), and hepatitis E.
Hepatitis B is the most common viral hepatitis worldwide, affecting as much as 10% of the adult population in endemic areas and causing approximately 780,000 deaths per year worldwide. It is most often transmitted vertically in areas of high incidence (perinatally) from mother to baby during birth) or horizontally by being exposed to infected blood or blood products. While less common, Hepatitis B can also be spread though exposure to mucous membranes. A vaccine is routinely given in the developed world.