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| Hepatitis B (HBV) is an infection of the liver
caused by the hepatitis B virus. The virus is spread by
direct exposure to the blood or body fluids, such as semen, of those infected
with HBV. Persons who inject drugs, who have a job that brings them into
contact with blood or who have multiple sexual partners are at risk of exposure
to HBV. As well, infected mothers can transmit the disease to their infants.
Symptoms include loss of appetite, nausea and vomiting, stomach pain, fatigue
and a yellowing of the skin and eyes (jaundice). Some people carry the virus
for the rest of their lives after infection; these people may develop cirrhosis
(scarring) of the liver, liver failure or liver cancer. HBV is preventable
through immunization. |
HEPATITIS B
AGENT OF DISEASE
Hepatitis B is caused by the hepatitis B virus (HBV), a hepadnavirus.
WORLDWIDE DISTRIBUTION
Hepatitis B occurs worldwide. In North America, infection occurs mainly
in young adults. In Africa and Asia, HBV infection commonly occurs in infants
and young children.
SYMPTOMS
Symptoms appear within 45 to 160 days (usually about 120 days) after exposure
to HBV. The severity of the illness ranges from cases with no or mild symptoms
to, uncommonly, severe cases that lead to liver failure. The number of cases
with no or mild symptoms is high: only 10% of children and 30% to 50% of adults
infected with HBV will have jaundice (yellowing of the skin and eyes). Other
symptoms may include loss of appetite, stomach pain, nausea and vomiting,
and occasionally joint pain and rash. Some people, especially infants and
children, infected with HBV never completely recover and carry the virus in
their blood for the rest of their lives. In some of these people there will
be persistent inflammation of the liver and possibly cirrhosis (scarring and
hardening) of the liver, liver failure and liver cancer.
PERIOD OF COMMUNICABILITY
The virus is in the blood several weeks before the onset of symptoms and
remains there throughout the course of the infection. People who permanently
carry the virus remain infectious to others.
HOW IT IS TRANSMITTED
Hepatitis B is spread through exposure to the blood or body fluids of those
infected with the virus. A person can become infected with HBV from sexual
contact with an infected person, sharing of injection equipment to inject
drugs, transmission from an infected mother to her infant, or exposure to
blood in the workplace. The risk of infection with HBV from a blood transfusion
is very low in Canada because blood is screened for HBV.
PREVENTION/CONTROL
- HBV vaccine is now given routinely in most provinces and territories to
young adolescents or to both infants and young adolescents.
- Hepatitis B vaccine is recommended for certain groups at higher risk of
infection with HBV.
- Street drugs should not be injected. If they are, injection equipment
must not be shared with others.
- Except in the case of an ongoing monogamous (one partner only) relationship,
safer sex must be practised, e.g., reducing the number of sex partners, using
a latex condom.
- Articles that might be contaminated with blood, e.g., toothbrushes, razors,
must not be shared.
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