Hepatitis B is a serious disease caused by a virus that attacks the liver. The virus, which is called hepatitis B virus (HBV), can cause lifelong infection, cirrhosis (scarring) of the liver, liver cancer, liver failure, and death.
Signs & symptoms
> About 30% of persons have no signs or symptoms.
> Signs and symptoms are less common in children than adults.
Symptoms develop within 30-180 days of exposure to the virus. The symptoms are often compared to flu. Most people think they have flu and never think about having HBV infection.
> Appetite loss
> Feeling tired (fatigue)
> Nausea and vomiting
> Itching all over the body
> Pain over the liver (on the right side of the abdomen, under the lower rib cage)
> Jaundice - A condition in which the skin and the whites of the eyes turn yellow in    color
> Urine becomes dark in color (like cola or tea).
Causes
> Use of needles and syringes contaminated with infected blood.
> Through needle sharing.
> Through mother to child.
> Unprotected sex with infected partner.
> Blood transfusion.
> Re-use of contaminated needle and syringe
Diagnosis
> The tests, called assays, for detection of hepatitis B virus infection involve serum or    blood tests that detect either viral antigens (proteins produced by the virus) or    antibodies produced by the host.
> The hepatitis B surface antigen (HBsAg) is most frequently used to screen for the    presence of this infection.
> It is the first detectable viral antigen to appear during infection.
> Shortly after the appearance of the HBsAg, another antigen named as the hepatitis B    e antigen (HBeAg) will appear.
> The presence of HBeAg in a host's serum is associated with much higher rates of viral    replication and enhanced infectivity
Treatment
> Hepatitis B infection does not usually require treatment because most adults clear the    infection spontaneously.
> There are four medications currently approved by the Food and Drug Administration    (FDA) for treatment of active hepatitis B infection.

1. Alfa Interferon.
2. Lamivudine: - inhibits hepatitis B viral DNA synthesis.
3. Adefovir dipivoxil (Hepsera): inhibits DNA polymerase activity and reverse transcriptase.
4. Baraclude (Entecavir): is the latest drug approved by the FDA for treatment of chronic hepatitis B. It works by inhibiting the function of Hepatitis B virus.