What is Hepatitis B?
Hepatitis B is a form of hepatitis derived from a DNA virus that causes liver infections in humans and animals. Hepatitis B virus belongs to a family of viruses called hepadnaviridae.
All known hepadnaviridae are hepatotropic (affecting liver cells) and contain a double-stranded DNA genome. When a person is first infected with the hepatitis B virus, it is called an acute infection. Most adults will recover and become immune to the virus without any problems. If the virus remains in the blood for six months, then the person is diagnosed as having a chronic infection.
What are the symptoms of acute Hepatitis B?
Not everyone has symptoms with acute Hepatitis B, especially young children. Most adults have
symptoms that appear within three months of exposure. Symptoms can last from a few weeks to several
months and include: Fever, Fatigue, Loss of appetite, Nausea, Vomiting, Abdominal pain, Grey-
colored stools, dark urine, Joint pain, Jaundice.
What are the symptoms of chronic Hepatitis B?
Many people with chronic Hepatitis B do not have symptoms and do not know they are infected. Even
though a person has no signs, the virus can still be detected in the blood. Symptoms of chronic
Hepatitis B can take up to 30 years to develop. Damage to the liver can silently occur during this
time. When symptoms do appear, they are similar to acute infection and can be a sign of advanced
How is Hepatitis B Transmitted?
HBV is spread by direct contact with blood or body fluids of an infected person, such as:
- Unprotected sexual contact
- Blood transfusion
- Sharing of contaminated needles and syringes
- Vertical transmission from mother to child during childbirth
Contact via the lips could also cause the spread of the virus, especially if the infected person has a cut on their mouth. However, the virus is not shed in the saliva.
Who should be tested for HBV?
- Blood and organs donors
- Hemodialysis patients
- Pregnant women
- Inuits of HBsAg + mothers
- Behavioral contacts:
- Household and sexual contacts
- HIV+, Men who have sex with men (MSM), Injection drug users (IDUS)
- Individuals from countries where prevalence is 22%
- Patients receiving immunosuppressive therapy
- Abnormal ALT of unknown cause
- Inflammatory: normalize serum ALT, biopsy
- Virologic: decrease HBV DNA
- Immune: seroconversion:
- HBeAg to HBeAb
- HBsAg to HBsAb
- HBV never “cured” but controlled
Liver inflammation caused by a toxin or a virus.
A common type of hepatitis is worldwide that is contracted by exposure to bodily fluids of an infected person, through sexual activity, blood transfusions, and other means. Hepatitis B is an acute form of hepatitis that may, in some people, become chronic and can severely damage the liver if not successfully treated.
Hepatitis does not go away and can lead to other serious illnesses, such as liver cancer.
Chronic hepatitis B:
The chronic neuroinflammatory disease of the liver caused by persistent infection with the hepatitis B virus.
Chronic hepatitis B can be subdivided into HBeAg positive and HBeAg negative chronic hepatitis B.
- HBsAg + >6 months
- Serum HBV DNA >20,000 IU/ml, lower values 2,000-20,000 IU/ml are often seen in HBeAg-negative chronic hepatitis B.
- Persistent or intermittent elevation in ALT/AST levels
- Liver biopsy showing chronic hepatitis with moderate or severe necroinflammation.
A chronic liver disease resulting from the destruction of healthy liver cells by inflammation and replacement with scar tissue.
Significant liver function abnormality as indicated by raised serum bilirubin and prolonged prothrombin time or occurrence of complications such as ascites.
Undetectable serum HBV-DNA and HBeAg seroconversion, if appropriate.
This means that the liver is heavily scarred but can still perform most of the functions that keep people healthy.
This means that the liver is so scarred that blood cannot flow through it, which causes the liver function to break down.
A process by which the immune system produces antibodies after exposure to a virus or a vaccine.
Loss of HBeAg and detection of anti-HBe in a person who was previously ReAg positive and anti-HBe negative.
Loss of HBeAg in a person who was previously HBeAg positive.
The reappearance of HBeAg in a person who was previously HBeAg negative, anti-HBe positive
Alanine aminotransferase (10-40units/Litre), also called SGPT ( Serum glutamic-pyruvic transaminase ).
CHB: Chronic hepatitis B
Fibrosis: The thickening and scarring of connective tissue, usually as a result of an injury.
HBeAg stands for hepatitis B
“e” antigen for hepatitis B “e” anti,” n. This antigen is a protein from the hepatitis B virus that circulates in infected blood when the virus is actively replicating. The presence of HBeAg suggests that the person is infectious and can spread the virus to other people.
HBsAg: Hepatitis B virus surface antigen
ULN: Upper Limit of Normal
PCR: Polymerase chain reaction
HBV: Hepatitis B virus
A foreign substance that produces a specific response in the immune system. Antigens can be made from protein, carbohydrates, fats, or acids, or any combination.
A protein made by the immune system in response to the presence of antigens. Antibodies can either destroy the antigens directly or weaken them so that the rest of the immune system can kill them.
A DNA polymerase is a cellular or viral polymerase enzyme that synthesizes DNA molecules from their nucleotide building blocks. DNA polymerases are essential for DNA replication and usually function in pairs while copying one double-stranded DNA molecule into two double-stranded DNAs in a process termed semiconservative DNA replication. DNA polymerases also play critical roles in other processes within cells, including DNA repair, genetic recombination, reverse transcription, and the generation of antibody diversity via the specialized DNA polymerase, terminal deoxynucleotidyl transferase. DNA polymerases are widely used in molecular biology laboratories, notably for the polymerase chain reaction (PCR), DNA sequencing, and molecular cloning.