hepatic and biliary disorders
Hepatitis B, Acute
Transmission of hepatitis B
HBV is often transmitted parenterally, typically via contaminated blood or blood products. Routine screening of donor blood for hepatitis B surface antigen (HBsAg) has nearly eliminated the previously common posttransfusion transmission, but transmission through needles shared by drug users remains common. Risk of HBV is increased for patients on dialysis and in oncology units, and for hospital personnel in contact with blood. Infants born to infected mothers have a 70 to 90% risk of acquiring hepatitis B during delivery (see Neonatal Hepatitis B Virus (HBV) Infection ) unless they are treated with The virus may be spread through mucosal contact with other body fluids (eg, between sex partners, both heterosexual and homosexual; in closed institutions, such as mental health institutions and prisons), but infectivity is far lower than that of hepatitis A virus, and the means of transmission is often unknown. The role of insect bites in transmission is unclear. Many cases of acute hepatitis B occur sporadically without a known source. Chronic HBV carriers provide a worldwide reservoir of infection. Prevalence varies widely according to several factors, including geography (eg,<0.5% in North America and northern Europe,>10% in some regions of the Far East and Africa). 