This document discusses hepatitis B virus (HBV) and hepatitis B. It defines hepatitis and the six main hepatitis viruses. It describes the structure and life cycle of HBV, including its virion structure and replication process. The document discusses the symptoms, modes of transmission, and outcomes of HBV infection. It provides global and national epidemiological data on HBV infection and details preventative measures like vaccination and immunoglobulin treatment.

2.  General concept
 Definitions of hepatitis
 Hepatitis B virus
 What is hepatitis
 Reservoir
 Causative agent and its structure
 Decoy partial
 Symptoms ,mode of transmission and RF
 Replication
 Epidemiology
 Preventions statistics

3.  Hepatitis = 'inflammation of the liver'.
 six medically important viruses are commonly
described as “hepatitis viruses”:
HAV,HBV,HCV,HDV,HEV,HGV.

5.  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.

6. Hepatitis B VirusHepatitis B Virus

7.  What is it?
 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

8.  Humans are the reservoir.

9.  Causative agent is Hep B virus
 Family: Hepadnaviridae
 Hepa: for liver
 Dna: for Deoxyribonucleic acid
 Virion (aka Dane particle):
 Outer lipid envelope
 Icosahedral nucleocapsid core composed of protein
 Outer envelope proteins:
 Binding & entry into susceptible cells
 Size: small, 42 nm in diameterStructure

10. HBVHBV : Structure: Structure

11. Dane particleDane particle
HBsAg = surface (coat) protein
HBcAg = inner core protein (a single serotype)
HBeAg = secreted protein; function unknown

12.  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.

14.  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

15. Replication of HBV

17.  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
Global Patterns of Chronic HBV Infection

18.  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

19.  Parenteral - IV drug abusers, health workers are
at increased risk.
 Sexual - sex workers and homosexuals are
particular at risk.
 Perinatal(Vertical) - mother(HBeAg+) →infant.
HBV:HBV: Modes of TransmissionModes of Transmission

20.  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

21. High Moderate
Low/Not
Detectable
blood semen urine
serum vaginal fluid feces
wound exudates saliva sweat
tears
breastmilk
Concentration of Hepatitis B Virus
in Various Body Fluids

22.  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

23. Incubation period: Average 60-90 days
Range 45-180 days
Insidious onset of symptoms.
Tends to cause a more severe disease than Hepatitis A.
Clinical illness (jaundice): <5 yrs, <10%
≥ 5 yrs, 30%-50%
1/3 adults-no symptoms
Clinical Illness at presentation 10 - 15%
Acute case-fatality rate: 0.5%-1%
Chronic infection: < 5 yrs, 30%-90%
≥ 5 yrs, 2%-10%
More likely in ansymptomatic infections
Premature mortality from
chronic liver disease: 15%-25%

24. Possible Outcomes of HBV InfectionPossible Outcomes of HBV Infection
Acute hepatitis B infection
Chronic HBV infection
3-5% of adult-
acquired infections
95% of infant-
acquired infections
Cirrhosis
Chronic hepatitis
12-25% in 5 years
Liver failureHepatocellular
carcinoma
Liver transplant
6-15% in 5 years 20-23% in 5 years
DeathDeath

25.  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.

26.  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.

27.  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.

28.  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

29.  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

30.  Interferon alfa (Intron A) Response rate
is 30 to 40%.
 Lamivudine (Epivir HBV) (relapse
,drug resistance)
 Adefovir dipivoxil (Hepsera)

31.  Vaccination
- highly effective recombinant vaccines
 Hepatitis B Immunoglobulin (HBIG)
-exposed within 48 hours of the incident/ neonates
whose mothers are HBsAg and HBeAg positive.
 Other measures
-screening of blood donors, blood and body fluid
precautions.