Читать книгу Basic Virology - Martinez J. Hewlett - Страница 81

Hepatitis B virus is related to but clearly distinct from retroviruses. Unlike the situation with HAV, the B virus is spread mainly through blood, either during sexual activity or during other blood contamination events (sharing of needles, for instance), and primary infection is sometimes followed by persistent viremia and liver damage. Hepatitis B infection is a special risk to medical personnel owing to the possibility of transmission by needle stick from contaminated blood, and the virus is endemic among intravenous drug users, commercial sex workers, and their customers. The disease is also endemic in Southeast Asia, where the virus can be spread from mother to infant by birth trauma.

Hepatitis B virus infection can lead to acute disease with attendant liver failure or can be asymptomatic. In many cases, virus is completely cleared, leading to full or partial recovery of liver function. Unfortunately, 5–10% of infected individuals go on to become asymptomatic chronic carriers of the virus. Indeed, chronic hepatitis B infections are a leading factor in human liver cancer. A third form of the hepatitis B virus infection (fulminant infection) is marked by rapid onset of extensive liver damage and often death. An effective vaccine against hepatitis B virus is now widely used to prevent infection.