What is hepatitis B?
Hepatitis B is a viral infection of the liver, which follows a very 
variable course. The hepatitis B virus (HBV) can cause an acute illness 
that resolves itself quickly without causing long-term liver damage. 
However, in about 20% of cases it causes a chronic illness that lasts 
more than six months, sometimes for life, with symptoms that come and 
go. In 15-40% of those with chronic infection cirrhosis, liver cancer or
 liver failure develop, and so the infection may eventually be fatal. 
Hepatitis
 B is not very common in the UK, with new infections occurring in about 7
 out of every 100,000 of the population every year, usually in adults. 
Worldwide, however, it is a major health problem. In Asia and most of 
Africa, most people pick up the infection around the time of birth or 
during childhood. As a result, two billion people worldwide are infected
 with hepatitis B, with 350 million suffering from chronic HBV 
infection. It is the 10th leading cause of death worldwide.   
The
 virus is usually transmitted through contact with infected blood or 
body fluids. Only a tiny amount of blood is needed to transmit the virus
 because it's so infectious. The hepatitis B virus may also be present 
in saliva, vaginal secretions, breast milk and other bodily fluids.
In
 the UK, infection commonly occurs through unprotected sexual 
intercourse, the sharing of contaminated needles by drugs users, 
accidental injury with a contaminated needle (if needles used for 
tattooing, body piercing or acupuncture are contaminated) and sharing 
razors.
In countries where screening of blood products isn't 
routine, or where medical equipment isn't adequately sterilised, 
hepatitis B may be transmitted during medical treatment. 
Many 
people contract hepatitis B while on holiday, especially in countries 
where it is very prevalent, when unprotected sex, experimenting with 
drugs and accidents needing medical treatment are far more likely. 
 
 Hepatitis B symptoms
The incubation period of the hepatitis B virus before symptoms develop is between six weeks and six months. 
In
 the acute phase symptoms vary. Roughly one-third of cases have no 
symptoms - this is called a silent or subclinical infection, or 
sometimes anicteric infection, meaning there is no jaundice or yellow 
appearance of the skin and membranes. In another third of cases, the 
infection causes mild symptoms similar to those of a flu-like illness, 
with weakness, aches, headache, fever, loss of appetite, diarrhoea, 
jaundice, nausea and vomiting.
In the final third of cases, the 
acute phase of infection can cause severe illness that last many months.
 In addition to the flu-like symptoms, there's abdominal pain, diarrhoea
 and jaundice.
Jaundice occurs in hepatitis infections because the
 liver becomes unable to remove a substance called bilirubin from the 
blood. This is a pigment that builds up in the body, causing the skin 
and whites of the eyes to turn yellow.
Rarely, rapid liver failure develops, which may need a life-saving liver transplant. 
In
 as many as one in five cases, the infection then goes into a chronic 
phase, where people may be apparently healthy with no symptoms but 
carrying and shedding the virus (known as healthy carriers). 
Alternatively, they may develop a chronic active hepatitis, with similar
 symptoms to the acute phase of the infection and also fatigue, poor 
appetite, nausea and abdominal discomfort. 
 
 Hepatitis B causes
In the UK, the people most at risk of contracting hepatitis B are 
injecting drug users, people who have unprotected sex with different 
partners, close family members of someone with the infection, babies 
born to infected mothers and travellers to high-risk countries who come 
into contact with infected blood and other bodily fluids. 
Hepatitis B is considered an occupational hazard for healthcare workers, the police and the emergency services.
 
 Preventing hepatitis B
Practising safe sex by using condoms and not sharing needles when 
using drugs can reduce the risk of infection. The same advice applies 
when travelling.
When having any body piercing, tattoo or 
acupuncture, make sure the business is registered with the local 
authority, that the needles used are disposable and that an autoclave is
 used for any equipment that's sterilised. If the proprietor cannot 
confirm these, go elsewhere.
Normal social contact carries no risk
 of infection. You can't catch hepatitis B from toilet seats or by 
touching an infected person. Clothing with the virus is thought to be 
killed by a normal hot wash in a washing machine, and by washing-up 
liquid and hot water for plates and cutlery.
 
 Hepatitis B vaccine
There's an effective vaccination to protect people from hepatitis B 
infection. It's available from your GP or high street travel centres, 
who will advise you whether you need it.
Family and other 
household members of an infected person should be vaccinated against 
hepatitis B. Healthcare workers, the police, the emergency services and 
anyone who is likely to come in contact with infected blood through 
their job should also be vaccinated.
 
 Hepatitis B treatments
The majority of people with hepatitis B don't need specific 
treatment other than rest, and they eventually make a full recovery. 
However, it is important that the infection is monitored to check 
whether chronic disease develops, and the person is given advice about 
the risk of passing the infection on.
If the infection lasts more 
than six months (chronic hepatitis infection, where the virus continues 
to actively reproduce in the body) you may need more specific drug 
treatment to reduce the risk of permanent liver damage (cirrhosis) and 
liver cancer. Your GP should refer you to a specialist in either liver 
disease (a hepatologist) or general digestive diseases (a 
gastroenterologist). They may recommend treatment either with treatment 
called interferon, or with antiviral drugs. 
Interferon (either 
alpha interferon or longer lasting pegylated interferon) is given as 
regular injections and helps boost the immune system to fight the 
infection. The response to interferon is variable, and some people who 
initially get better get worse again when the treatment is stopped. 
Others find that the side effects of interferon mean that they cannot 
continue with treatment.
Several different antiviral drugs, known 
as nucleoside analogues, are also now used to treat chronic hepatitis. 
They aren't a cure, but they do suppress the virus. These drugs may also
 have side effects - although not usually so severe as with interferon -
 and the virus may become resistant to them. 
Occasionally, when there is severe damage to the liver, a liver transplant is recommended.
READMORE:
http://www.bbc.co.uk/health/physical_health