Viral hepatitis--a primer: 1. Epidem.iology.

Hepatitis A is most often transmitted by the fecal-oral route under conditions of crowding, poor hygiene, and prolonged exposure to infected persons. Direct spread of hepatitis B via person-to-person contact has only recently been proved. Hepatitis B is usually transmitted indirectly by percutaneous routes, and the increase in drug abuse has brought about a change in its epidemiologic pattern.