This document summarizes information about Hepatitis B virus (HBV) including its structure, antigens, modes of transmission, clinical features, diagnosis, and prevention. HBV is a 42nm enveloped virus containing Hepatitis B surface antigen (HBsAg) and Hepatitis B core antigen (HBcAg) which encloses the viral DNA. It is transmitted parenterally, perinatally, or sexually. Clinical features include a pre-icteric, icteric, and convalescent phase. Diagnosis involves detecting antigens and antibodies. Prevention includes immunization with plasma-derived or recombinant yeast vaccines.

1. MAN BAHADUR RANA
BPH,ACAS,NEPAL

5. - HBV is a complex 42 nm double shelled
particle.
- The outer surface or envelope of virus
contains Hepatitis B surface antigen ( HBsAg).
- It encloses an inner icosahedral 27nm
nucleocapsid (core), which contain hepatitis B
core antigen (HBcAg).
- Inside the core is the genome, a circular
double stranded DNA and a DNA polymerase.

6. 1. HBsAg:
- Surface antigens (envelope protein).
- It is made up of lipid, protein and
carbohydrate.
2. HBcAg :
- It is the core(nucleocapsid) antigen of the
virus
- It is not detectable in patients blood.

7. 3. HBeAg:
- It appears in serum along with HBsAg but
disappears within a few weeks.
- HBcAg and HBeAg though
immunologically distinct are coded by the
same gene.

8. There are three important modes of transmission
of HBV infection.
1. Parenteral
2. Perinatal
3. Sexual
Parenteral:
- Transmission of infection may result from
accidental inoculation of minute amounts of
blood, blood products or fluid containing HBV
during medical, surgical or dental procedure.

9. - Needlestick injuries, use of contaminated
needles and syringes, intravenous and
percutaneous drug abuse, ear and nose
piercing, tattooing, acupuncture, sharing of
shaving razor and kissing can transmit HBV
infection.
Perinatal:
- Transmission probably occurs when
carrier mothers blood contaminates the
mucous membranes of the new born during
birth.

10. Sexual Transmission:
- HBV is present in body fluids such as
semen and vaginal secretions, hence it can be
transmitted by sexual contact.
- Male homosexual are at higher risk of
acquiring infection.

11. Clinical features:
- The incubation period varies from 6 weeks
to 6 months.
- The course of acute HBV infection can be
divided into three phase.
. Pre-ecteric
. Icteric
. Convalescent

12. Pre-icteric phase:
In this phase patient develops malaise,
anorexia, weakness, nausea and vomiting
Icteric phase:
Patient develops jaundice, pale stools,
and dark urine.(bilirubinuria).
Convalescent phase:
This phase is long and drawn out with
malaise and fatigue.

13. 1. Laboratory diagnosis of HBV infection can
be carried out by detection of hepatitis B
antigen and antibodies.
These can be detected by sensitive and
specific tests like ELISA and RIA.
2. Viral DNA Polymerase:
It appears transiently in serum during pre-
icteric phase.

14. 3. Polymerase chain infection:
HBV DNA level can be detected in serum
by PCR . It is a highly sensitive test.
Biochemical test:
- SGPT and SGOT level increases
- Serum bilirubin level indicates the degree
of jaundice and may rise up to 25 fold.

15. - General Preventive Measure
- Immunisation
General Preventive Measure:
 These include health education ,
improvement of personal hygiene.
 Use of unsterile needle, syringes and other
material must be avoided to prevent hepatitis
B infection.

16. i) Passive immunization:
- Passive immunization may be employed
following any accidental exposure to hepatitis B
infection.
- It can be given in doses of 300-500 IU
intramuscularly.
- Vaccine should be administered as early as
possible after exposure, preferably with in 48
hours.
- A second dose is given at an interval of 4
weeks, after the first dose.

17. - It may not prevent infection but protect
against illness and the development of carrier
state.
ii) Active immunization:
Following vaccines are available
a) Plasma derived vaccine
b) Recombinant yeast hepatitis B Vaccine.

18. a) Plasma derived vaccine:
- It consist of purified 22nm particles of
HBsAg, prepared from the plasma of
symptomless carriers.
- The particles are seperated by
ultracentrifugation and treated with
proteinase, 8M urea and formaldehyde.
- This vaccine is still being produced and
used particularly in developing countries
where the need is greatest.

19. b) Recombinant yeast hepatitis B Vaccine:
 It is produced by cloning the HBsAg gene in
yeast Saccharomyces cerevisae and the HBsAg
particles produced are extracted and purified
for use as vaccine.
 This vaccine is safe, antigenic, free from
side effects and as immunogenic as plasma
derived vaccine.