Hepatitis B Virus (HBV) and Its Vertical Transmission

Book

Ali, Bahy Ahmed . 2015

• Publication Work Type: Book
• Publishing City: Saarbrucken, Germany
• Publisher Name: LAP Lambert Academic Publishing, Editor: aberdos, ISBN: 978-3-659-71140-4

Publication Abstract

The Hepatitis B virus (HBV) is a mostly double-stranded DNA virus in the

Hepadnaviridae family. HBV is a common viral pathogen that causes a substantial

health burden worldwide. Significant progress has been made in the past few decades

in understanding the natural history of HBV infection (Pungpapong et al., 2007).

One of five hepatitis viruses, HBV causes acute and chronic hepatitis in humans.

Despite the current availability of an effective vaccine, almost 1.2 million people

worldwide still die each year from HBV related diseases (Center for Disease Control

CDC). An acute HBV infection usually causes only mild symptoms and the majority

of infected adults successfully clear the virus and acquires life-long immunity. In

acute hepatitis, it takes about 1 to 6 months from the time of infection for the disease

to manifest itself. Early symptoms include nausea and vomiting, loss of appetite,

fatigue, and muscle and joint aches. Jaundice, together with dark urine and light

stools, follows. Only about 1 percent of patients infected with hepatitis B die due to

liver damage in this early stage. The risk of becoming chronically infected depends

on the age at the time of infection. More than 90 percent of newborns, 50 percent of

children, 5 percent of adults infected with HBV develop chronic hepatitis. Those who

are unable to produce an effective immune response allow the virus to replicate for

long periods in their livers, causing chronic hepatitis HBV infection, cirrhosis of the

liver, and hepatocellular carcinoma (HCC) (Yen, 2002). Transmission of the hepatitis

B virus is through contact with blood and other bodily fluid. Chronic hepatitis B is

treated with a manufactured form of interferon, a protein made naturally by the body

to boost the immune system and to regulate other cell functions (CDC). A vaccine is

available to prevent HBV which originally consisted of purified HBV surface

antigens (HBsAg) prepared from the serum of carriers and wash chemically treated to

kill any contaminating viruses, but the current vaccine is genetically engineered

HBsAg produced in yeasts ((Yen, 2002).