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| You are in>Health Channels>Diseases>Hepatitis B |
| Hepatitis B |
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| Introduction: |
| Hepatitis B is a viral infection of the liver caused
by the Hepatitis B Virus (HBV), transmitted mainly through blood and body secretions. Man
is the only reservoir of the infection, which is spread either by carries or cases. A
carrier is a person who harbours the virus but shows no symptoms of the disease.
Contaminated blood is the main source of infection, however the virus has also been
demonstrated in saliva, vaginal secretions and semen. Its main modes of transmission are
parental (i.e. through infected blood and blood products, dialysis, contaminated syringes
and instruments, traditional tattooing, ear and nose piercing, shared razors and blades
etc), mother to baby at the time of birth and sexual contact. Usually hepatitis B is an
acute self-limiting illness, at times sub-clinical or asymptotic. However in few persons
the HBV infection fails to resolve and the affected individual then becomes a persistent
carrier of the virus. The probability of an infant becoming a carrier if infected is
65-90%. The probability reduces to 50% at three years and 6-10% at 6 years. Persistent HBV
infection may cause progressive liver disease including chronic active hepatitis,
cirrhosis and liver malignancy in approximately 30% carriers.
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| Epidemiology: |
| Hepatitis B is a major public health problem in
India. During 1992, a total of 98,047 cases and 1268 deaths of viral hepatitis were
reported, of which 30-40% are likely to be Hepatitis B. However since many cases go
unreported or unrecognised, the actual number of Hepatitis B cases may be anybody’ s
guess. Although acute Hepatitis B is important, most of the mortality and morbidity occurs
in chronic cases and HBV infection is directly linked to 1-2 million deaths per year. Of
the 350 million carries of HBV, India alone has more than 35 million, i.e. 10% of the
world’s carriers. Almost 30% of these carriers who survive more than 30 years are
likely to develop chronic liver disease or liver cancer. back to top |
| Symptoms: |
| Along incubation period, a protracted illness and
variable outcomes characterise the infection. Symptoms include jaundice, yellowness of
skin and sclera, dark urine, anorexia, vomiting and fever. Diagnosis is done by testing
blood for the hepatitis B surface antigen, also called Australia antigen.
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| Who are
at a greater risk: |
- Infants born to mother who has the infection
- Healthcare workers including laboratory staff
- Recipients of blood or blood products
- Patients on haemodialysis
- Mentally retarded persons living in institutions
- Sex workers
- Drug addicts.
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| Treatment of chronic hepatitis B
infection: |
| Interferon was the main stay in the management of
chronic HBV infection. However it has a limited response, high cost and
dose limiting side effects. Moreover it has low effectivity in childhood acquired
infections, and in India considerable proportions of infections are acquired in childhood.
It is only recently that an effective oral drug has become available for the treatment
chronic HBV infection. Lamivudine a drug used for the treatment of AIDS has been found to
be highly effective in the treatment of chronic HBV infection. It is also effective in
childhood acquired infections and infections which procure mutant strains (a variant of
HBV) which is prevalent in Asia. Almost 40% of the infections in Asia are thought to be
due this prevalent strain. This mutant strain does not respond to interferon. Moreover
Lamivudine is taken orally as a single dose and is very safe. The availability of this
drug in India is expected to revolutionise the treatment of HBV in our country.
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| Prevention
of HBV infection: |
| Using simple measures can effectively
prevent HBV infection. These include screening of blood donors, use of disposable,
adequate sterilisation of reusable surgical instruments, proper disposal of contaminated
wastes etc. However vaccination is the single most effective way of preventing spread of
infection and vaccination provides more than 96% protection after a three-dose schedule
(0,1 & 6 months). Although the vaccine can be given at any stage it is most
effective when administered in infancy as the highest chances of developing chronic
infection is in early childhood. Moreover the childhood dose being half the adult dose the
cost of vaccination is also reduced. WHO recommends universal immunisation of infants.
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