Hepatitis B
More details/information for students
Definition
Symptoms
Statistics
Transmission
Testing
Treatment
Prevention
Hepatitis B is a virus which affects the liver.
Most people who are exposed to hepatitis B do not become
ill, they carry the virus for a short period of time and then become
immune ie protected against further infection. Some people do develop an
acute illness and then become immune. Signs and symptoms can include:
- a general lack of energy
- loss of appetite
- nausea and vomiting
- jaundice - yellow skin and eyes, dark urine, pale
faeces
- tender, enlarged liver on examination.
Between 5% and 10% of adults, and the majority of
infants who are infected with hepatitis B, remain carriers of the virus
and are potential sources of infection to others. Liver failure occurs in
less than 1% of cases but carriers are at increased risk of developing
chronic persistent hepatitis which can lead to cirrhosis of the liver or
liver cancer.
Carrier rates vary in different parts of the world eg
0.1 - 0.2% among Caucasians in Australia, United States and Northern
Europe; 1 - 5% in Mediterranean countries, parts of Eastern Europe,
countries of the former USSR, China, Africa, Central and Southern America
and greater than 10% in some Australian Aboriginal, Central African, and
South East Asian populations.
Higher carrier rates than those found in the general
population are also associated with injecting drug use, prostitution and
unprotected male to male anal intercourse.
See Statistics page
for more information.
Transmission of infection involves the exchange of body
fluids including semen, vaginal fluid and blood. This includes inoculation
or mucosal contact. Viral particles also occur in other body fluids such
as saliva, tears and breast milk . Transmission by inadvertent parenteral
inoculation through close personal contact in households in which a
carrier resides is a potential but low risk.
Common sources of infection are:
- Blood exposure from sharing of needles and syringes
when injecting drugs, tattooing, blood transfusions or accidental
needlestick injury. In the home environment sharing of razors and
tooth brushes with some one who is a carrier.
- Sexual intercourse - vaginal, anal or oral sex.
- Mother to baby at or around the time of birth.
A blood test is necessary to diagnose hepatitis B.
Treatment may involve hospitalisation for the more
serious cases. There is no special treatment other than rest and a bland
diet. Liver function tests should be performed weekly at first, then
monthly. It is important that people recovering from hepatitis B are
symptom-free and have normal liver function tests before they return to
work.
- Screening of blood and organ donors has virtually
eliminated the risk of transmission from blood or organ transplants.
- Vaccination of those groups in the community at
higher risk of infection including:
- infants born to carrier mothers
- infants and young children of ethnic groups with
high carrier rates
- sexual and household contacts of acute cases or
carriers of hepatitis B
- occupational groups at risk of exposure such as
health care workers
- injecting drug users
- men who have sex with men
- prostitutes.
- Condom use for vaginal, anal and oral sex.
- Use of clean needles and syringes during injecting
drug use.
Vaccination consists of a course of 3 injections over a
6 month period.
A single dose of hepatitis B immunoglobulin given within
7 days of exposure to infection is available for immediate protection of
susceptible individuals.
Reference:
National Health and Medical Research Council (1994) The
Australian Immunisation Procedures Handbook, fifth edition, AGPS. |
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