This document summarizes information about Hepatitis B virus (HBV). It defines hepatitis and the different types. HBV is described as a serious virus that infects the liver and can cause lifelong infection. Humans are the reservoir for HBV. The virus is spherical and has an outer envelope and inner nucleocapsid core. HBV is transmitted through bodily fluids and from mother to child. Symptoms can include jaundice and fatigue. Hundreds of millions of people worldwide are chronically infected. Prevention includes vaccination and immunoglobulin treatment for exposed newborns.

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Amjad Khan Afridi
Hepatitis B Virus
Contents
Generalconcept
Definitionsof hepatitis
HepatitisB virus
Whatis hepatitis
Reservoir
Causativeagentand its structure
Decoypartial
Symptoms,mode of transmission and RF
Replication
Epidemiology
Preventionsstatistics
Epidemiology Notes
Madam Saira

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General Concepts
Hepatitis = 'inflammation of the liver'.
six medically important viruses are commonly described as “hepatitis viruses”:
HAV,HBV,HCV,HDV,HEV,HGV.
Definitions for Hepatitis
 Acute: Short term and/or severe.
 Chronic: Lingering or lasting - may or may not be severe
 Fulminant: Developing quickly and lasting a short time, high mortality rate.
 Cirrhosis: Hardening: may be the result of infection or toxins (e.g. alcohol)
 Jaundice: Yellowing of the skin, eyes,etc due to raised levels of bilirubin in the blood due to
liver damage.
 Hepatocellular carcinoma： is closely associated with hepatitis B, and at least in some regions
of the world with hepatitis C virus.

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Hepatits B
What is Hepatits B?
Hepatitis B is serious disease caused by a virus that infect the liver.
Can cause lifelong infection, cirrhosis (liver scarring), liver cancer,liver failure and death Hepatitis B.
Reservoir ofhepatitis B virus
 Humansare the reservoir.
Causative agent and its structure
 Causative agent is Hep B virus
 Family: Hepadnaviridae
 Hepa: for liver
 Dna: for Deoxyribonucleic acid
 Virion (aka Dane particle):
 Outer lipid envelope
 Icosahedralnucleocapsid core composed of protein
 Outer envelope proteins:
 Binding & entry into susceptible cells
 Size: small, 42 nm in diameterStructure
HBV Structure

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Decoy particles
 HBsAg-containing particles are released into the serum of infected people and outnumber the
actual virions.
 Spherical or filamentous
 They are immunogenic and were processed into the first commercial vaccine against HBV.
GENOME

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HBV Replication
 Reverse transcription: one of the mRNAs is replicated with a reverse transcriptase making the
DNA that will eventually be the core of the progeny virion
 RNA intermediate: HBV replicates through an RNA intermediate and produces and release
antigenic decoy particles.
 Integration: Some DNA integrates into host genome causing carrier state .
Global Patterns of Chronic HBV Infection
 High (>8%): 45% of global population
 lifetime risk of infection >60%
 early childhood infections common
 Intermediate (2%-7%):43% of global population
 lifetime risk of infection 20%-60%
 infections occur in all age groups
 Low (<2%): 12% of global population
 lifetime risk of infection <20%
 most infections occur in adult risk groups

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Symptoms
 Nausea
 Loss of appetite
 Vomiting
 Fatigue
 Fever
 Dark urine
 Pale stool
 Jaundice
 Stomach pain
 Side pain
 A person may have all, some or none of these
HBV Modes of Transmission
 Parenteral- IV drug abusers, health workers are at increased risk.
 Sexual - sex workers and homosexuals are particular at risk.
 Perinatal(Vertical) - mother(HBeAg+) →infant.
High-risk groups for HBV infection
 Injection drug users
 Sex partners of those with Hep B
 Sex with more than one partner
 Men who have sex with men
 Living with someone with chronic Hep B
 Contact with blood
 Transfusions, travel, dialysis

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Pathogenesis & Immunity
 Virus enters hepatocytes via blood
 Immune response (cytotoxic T cell) to viral antigens expressed on hepatocyte cell surface
responsible for clinical syndrome
 5 % become chronic carriers (HBsAg> 6 months)
 Higher rate of hepatocellular ca in chronic carriers, especially those who are “e” antigen positive
 Hepatitis B surface antibody likely confers lifelong immunity (IgG anti-HBs)
 Hepatitis B e Ab indicates low transmissibility
Clinical Features

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Statistics on HBV:
 Most healthy adults (90%) who are infected will recover and develop protective antibodies
against future hepatitis B infections
 90% of infants and up to 50% of young children infected with hepatitis B will develop chronic
infections.
Hepatitis B In the World
 2 billion people have been infected (1 out of 3 people).
 400 million people are chronically infected.
 10-30 million will become infected each year.
 An estimated 1 million people die each year from hepatitis B and its complications.
 Approximately 2 people die each minute from hepatitis B.
Hepatitis B In the United States
 12 million Americans have been infected (1 out of 20 people).
 More than one million people are chronically infected .
 Up to 100,000 new people will become infected each year.
 5,000 people will die each year from hepatitis B and its complications.
 Approximately 1 health care worker dies each day from hepatitis B.
Hepatitis B in China
 1.3 billion people
 the world's largest population of hepatitis B patients, with nearly half a million people dieing of
the liver disease every year
 120 million Chinese have tested positive for hepatitis B, which has become a severe public health
problem in the country
Epidemiology
 350,000,000 carriers worldwide
 120,000,000 carriers in China
- the carrier rate can exceed 10%
- 15 to 25% of chronically infected patients will die from chronic liver disease
 500,000 deaths/year in China
 982,297 liver disease in China 2005
 50% of children born to mothers with chronic HBV in the US are Asian American

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Current Treatment Options
 Interferon alfa (Intron A) Response rate is 30 to 40%.
 Lamivudine (Epivir HBV) (relapse ,drug resistance)
 Adefovir dipivoxil (Hepsera)
Prevention
 Vaccination
- highlyeffectiverecombinantvaccines
 HepatitisBImmunoglobulin(HBIG)
- exposedwithin48hours of the incident/neonateswhose mothersare HBsAgand
HBeAgpositive.
 Othermeasures
- screeningof blooddonors,bloodandbodyfluidprecautions.
PreparedBy Amjad Khan Afridi
Date : 22 May, 2016