Microbiology Seminar, 3rd stage.

1. Hepatitis B Virus
Huzaifa Hamid Ahmad
Peshraw Karim Abdurrahman
Shanyar Kadir Hamakarim
Shkar Dilshad Abdulkarim
Shvan Omar Siddiq

2. Causes of Hepatitis:
drugs
toxins
alcohol
viral infections (A, B, C, D, E)
other infections (parasites, bacteria)
physical damage
What is hepatitis?

3. Functions
Stores sugar needed for energy
Absorbs good nutrients
Breaks down poisons (toxins) and drugs
Makes important proteins that help build new tissue and
repair broken tissue
Produces bile, which helps remove waste from the body
Liver

4. Acute Hepatitis: Short-term hepatitis.
Body’s immune system clears the virus from the body
within 6 months
Chronic Hepatitis: Long-term hepatitis.
Infection lasts longer than 6 months because the body’s
immune system cannot clear the virus from the body
Hepatitis Terms

5. Hepatitis B Virus
CDC website: http://www.cdc.gov/ncidod/diseases/hepatitis/slideset/hep_b/slide_1.htm

6. What is it?
Hep B is a serious disease caused by a virus that infects
the liver
Can cause lifelong infection, cirrhosis (liver
scarring), liver cancer, liver failure and death
Hepatitis B

7. 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 diameter
Structure

9. Circular DNA
Unusual, partially double stranded
Long strand: 3020–3320 nucleotides
Short strand: 1700–2800 nucleotides
One end of the long strand is linked to the viral DNA
polymerase
Genome

11. Nomenclature for Hepatitis B Virus
components

12. Hepatitis B Virion, Dane particle and HBsAG

13. 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
HBV: Replication

14. Clinical outcomes of Hepatitis B
infections
From Murray et. al., Medical Microbiology 5th edition, 2005, Chapter 62, published by Mosby Philadelphia,,

15. Determinants or acute and chronic HBV
infection
From Murray et. al., Medical
Microbiology 5th
edition, 2005, Chapter
66, published by Mosby
Philadelphia,,

16. Child-to-child
Contaminated needles
Sexual contacts
Healthcare worker
Blood transfusion
• 6% of
people
infected over
the age of 5
become
chronically
infected
Perinatal
• 90% of
infected
infants
become
chronically
infected
Perinatal transmission Horizontal transmission
Transmission of HBV
CDC. Available at: http://www.cdc.gov/hepatitis. Accessed December 2006.
Lee WM. N Engl J Med. 1997;337:1733-1745.
Lavanchy D. J Viral Hepat. 2004;11:97-107.
HostMother
Infant
Recipient

17. Hepatitis B is NOT transmitted through food/water.
Hepatitis B is NOT transmitted through casual contact
such as hugging or shaking hands.
Hepatitis B is NOT transmitted through kissing, sneezing
or coughing.
Hepatitis B is NOT transmitted through breastfeeding.
What are some common myths and
misconceptions about Hepatitis B?

18. Diagnostic tests
HBsAg
HBeAg
HBV-DNA
HBcAb
IgM
HBcAb
IgG
HbsA
b IgG
Acute
infection + + - -
Prior
infection - - + +
Chronic
infection-
carrier
+ + + -
Immunizat
ion - - - +
Windo
w
period
only
HBc Ab
is +

19. Hepatitis B acute infection
CDC website: http://www.cdc.gov/ncidod/diseases/hepatitis/slideset/hep_b/slide_3.htm
Note:
Pattern of
serological
markers
varies
depending
on
whether
the
infection if
acute or
chronic

20. Chronic Hepatitis B infection
http://www.cdc.gov/ncidod/diseases/hepatitis/slideset/hep_b/slide_4.htm
Notes:
In patients with chronic
HBV infection, both HBsAg
and IgG anti-HBc remain
persistently
detectable, generally for
life. HBeAg is variably
present in these patients.
The presence of HBsAg for
6 months or more is
generally indicative of
chronic infection. In
addition, a negative test for
IgM anti-HBc together with
a positive test for HBsAg in
a single serum specimen
usually indicates that an
individual has chronic HBV
infection.

21. 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
Who is at highest risk?

22. Prevent perinatal HBV transmission
Routine vaccination of all infants
Vaccination of children in high-risk groups
Vaccination of adolescents
Vaccination of adults in high-risk groups
Prevention

23. Composition Recombinant HBsAg
Efficacy 95% (Range, 80%-100%)
Duration of
Immunity 20 years or more
Schedule 3 Doses
Booster doses not routinely recommended
Hepatitis B Vaccine

24. Nausea
Loss of appetite
Vomiting
Fatigue
Fever
Dark urine
Pale stool
Jaundice
Stomach pain
Side pain
Symptoms
A person may have all, some or none of these

25. FDA approved
Interferon Alfa
Lamivudine – reverse transcriptase inhibitor
Adefovir – nucleotide analogue that inhibits viral
polymerase
Investigational
Tenofovir – adenine nucleotide analogue
Approved for HIV
Entecavir – guanosine analogue, highly selective for the
HBV polymerase
Treatment options

26. 1/3 of world’s population
has been infected
350 million with chronic
disease
15-25% of these die due to
liver related diseases
1 million deaths annually
United States
1.25 million chronic carriers
5000 deaths annually
Hepatitis B epidemiology
Figure 66-9. Worldwide prevalence of hepatitis B
carriers and primary hepatocellular carcinoma.
(Courtesy Centers for Disease Control and
Prevention, Atlanta.)

27. Notes:
HDV infection can be acquired either as a co-infection with HBV or as a superinfection of persons with chronic HBV
infection. Persons with HBV-HDV co-infection may have more severe acute disease and a higher risk of fulminant
hepatitis (2%-20%) compared with those infected with HBV alone; however, chronic HBV infection appears to occur
less frequently in persons with HBV-HDV co-infection. Chronic HBV carriers who acquire HDV superinfection usually
develop chronic HDV infection. In long-term studies of chronic HBV carriers with HDV superinfection, 70%-80%
have developed evidence of chronic liver diseases with cirrhosis compared with 15%-30% of patients with chronic
HBV infection alone.
CDC website: http://www.cdc.gov/ncidod/diseases/hepatitis/slideset/hep_d/slide_1.htm

28. Key features of Hepatitis Delta Virus
•Single stranded, self complementary RNA,
encapsidated in HbsAg
•Small, amorphous particle
•RNA encodes one protein: delta antigen
•Replicates via RNA directed RNA synthesis,
catalyzed by host RNA polymerase II

29. Key features of Hepatitis Delta Virus
•Delta antigen required for replication, role unknown
•Dependent on HBV as a “helper”
•HBV provides HbsAg
•May be acquired as co-infection with HBV, or
superinfection of HBV infection
•Exacerbates HBV induced disease

30. Hepatitis Delta Virion
From Murray et. al., Medical
Microbiology 5th edition, 2005,
Chapter 66, published by Mosby
Philadelphia,,
Figure 66-14

31. Consequences of hepatitis B and delta virus infection
Figure 66-15. Consequences of deltavirus infection. Deltavirus (d) requires the presence of
hepatitis B virus (HBV) infection. Superinfection of a person already infected with HBV
(carrier) causes more rapid, severe progression than co-infection (shorter arrow).
From Murray et. al., Medical Microbiology 5th edition, 2005, Chapter 66, published by Mosby Philadelphia.

32. Thank You 