Hepatitis B virus (HBV) is a small, enveloped DNA virus.
HBV infects the liver and can lead to both acute and chronic liver diseases.
HBV belongs to a group of hepatotropic DNA viruses (hepadnaviruses).
3. What is Hepatitis B virus?
Hepatitis B virus (HBV) is a small, enveloped
DNA virus.
HBV infects the liver and can lead to both
acute and chronic liver diseases.
HBV belongs to a group of hepatotropic
DNA viruses (hepadnaviruses).
5. Roughly spherical, diameter: 42nm
Icosahedron capsid
HBV virion Non – infectious particles
Abundant smaller spherical and
filamentous forms lack nucleocapsid and
are not infectious.
8. CAPSID
The capsid has holes and short spikes protrude
from its surface. It is constructed from dimers of
the C (core) protein, which is largely α-helical,
unlike other viruses.
9. THE GENOME
•Four ORFs, from which seven proteins are translated.
•DR1 and DR2 involved in reverse transcription.
•The genome is made up of two
strands of DNA, one of which is
incomplete.
•Because of small genome, that
all the regulatory sequences,
such as promoters, are within
protein coding sequences.
10. Surface proteins (HBsAg): involved in envelope and non-infectious particles formation.
Core protein (HBcAg): major component of the nucleocapsid.
The E protein (HBeAg): may suppress the host immune system and prevent it from eliminating cells
that contain hepatitis B virus.
Polymerase protein: plays a critical role in hepadnavirus genome replication and pregenome RNA
encapsidation.
Protein X: stimulates viral gene transcription.
HEPATITIS B VIRUS PROTEIN
24. CLININAL FEATURES
Incubation period 60 to 90 days.
Clinical signs and symptoms more common in adults.
PHASE 1
Prodromal phase
• lasts 3 to 10 days.
• abrupt onset of fever,
malaise, anorexia,
nausea, abdominal
discomfort, and dark
urine before jaundice.
PHASE 2
Icteric phase
• lasts 1 to 3 weeks.
• jaundice, light or gray
stools, hepatic
tenderness,
hepatomegaly.
PHASE 3
Convalescent phase
• lasts weeks to months.
• malaise and fatigue
persist while jaundice,
anorexia, and other
symptoms disappear.
Most adults recover while most infants progress to chronic infection.
25. CHRONIC HBV INFECTION
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Infant Childrent 1-5 years Adulthood Hemodialysis patient Patients with immune
deficiencies
Proportion of people with acute HBV that progress to chronic HBV
● Often asymptomatic
● Responsible for most
HBV-related morbidity
and mortality.
27. TRANSMISSION
Horizonal transmission
Transmission from mother
to child during childbirth
Vertical transmission
infectious blood or body
fluids containing blood
sexual contact and
blood transfusions
contaminated needles
and syringes
transmitted between family
members within households
30. TREATMENT
There is no specific treatment for acute hepatitis B.
Chronic hepatitis B can be treated with medicines.
Chronic hepatitis B infection can be treated with:
Oral medicines, including tenofovir or entecavir.
Liver transplant.
The two immune system modulators:
Interferon α – 2a
31. QUESTIONS
What type of proteins made up the envelope?
Name 4 size classes of RNA that are translated from cccDNA?
Can you tell some ways to prevent HBV?
Can you name the antibody in HBV?
32. TAKE NOTE!
Unusual partly single-stranded, partly double-stranded circular genome results
from incomplete genome replication in cell.
Pregenome RNA is both an mRNA and a template for synthesis of genome DNA
Reverse transcriptase (polymerase protein) generates genome DNA from
pregenome RNA within capsid during virus assembly.
Makes large amounts of non-infectious spherical and filamentous particles.
(giải thích cơ chế tạo vòng của DNA: (đặt câu hỏi cho nhóm) The covalently bound P protein is removed from the 5 end of the minus strand, which is shortened to remove the third strand of the triple-stranded region. The RNA is removed from the 5 end of the plus strand, while DNA synthesis at the 3 end makes the entire molecule double-stranded. The ends of each strand are then ligated to form covalently closed circular DNA (cccDNA))
