Hepatitis A, B and nAnB: The Viruses and their Prevention.

THREE VIRUSES COMMONLY INFECT THE LIVER: hepatitis A virus (HAV), hepatitis B virus (HBV) and the virus(es) responsible for non A non B hepatitis (nAnB). HAV infection occurs predominantly by the fecal-oral route and thus is more common in areas where living conditions are poor and personal hygiene suboptimal. Immune serum globulin (ISG) prevents this form of hepatitis. HBV infection can be spread by either parenteral (e.g. drug abuse) or non-parenteral (e.g. intimate contact) routes. High risk, susceptible individuals should be vaccinated with the HBV vaccine for longterm protection. Hepatitis B immune globulin (HBIG) remains the treatment of choice after exposure, but its protective effect does not exceed three to four months. The nAnB agent is spread by the same routes as HBV infection. At present there is no convincing evidence that any form of active or passive prophylaxis is beneficial for this form of hepatitis.