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Hepatitis B

Publié par happy-diet dimanche 23 mai 2010


Hepatitis B




Key points

* The Hepatitis B is a viral infection that attacks the liver. It is the source of acute and chronic disease.
* The virus is spread by contact with blood or other body fluids of an infected person, not through casual contact in daily life.
* Approximately two billion people are infected worldwide and nearly 350 million live with chronic liver disease. Approximately 600,000 people die each year.
* The risk of death from cirrhosis or liver cancer caused by hepatitis B. About 25% of adults who become chronically if the infection occurred in childhood.
* The virus of hepatitis B is 50-100 times more infectious than HIV.
* The hepatitis B is a major occupational hazard for health workers.
* The vaccine is safe and effective prevention of hepatitis B.

Hepatitis B is a potentially fatal liver infection caused by hepatitis B. It is a major health problem worldwide and the most severe form of viral hepatitis. It can cause chronic liver disease and puts people at high risk of death from cirrhosis or liver cancer.

An estimated two billion people infected with hepatitis B virus (HBV) and more than 350 million have chronic infection (long time).

We have a vaccine since 1982. The vaccine is effective in 95% to prevent HBV infection and its chronic consequences, and it was the first vaccine against one of the major human cancers.

Symptoms

The hepatitis B can cause an acute illness with symptoms that last for several weeks including yellowing of the skin and eyes (jaundice), dark urine, extreme fatigue, nausea, vomiting and abdominal pain . It can take several months to a year to recover. The hepatitis B can also cause chronic liver infection that is changing at a later stage to cirrhosis or cancer.
Who is most at risk of chronic disease?

The probability that infection with hepatitis B becomes chronic depends on the age at which infection occurs, infected young children with the greatest probability of becoming chronic carriers. About 90% of infants infected during the first year of life develop chronic infection, and between one and four years, this proportion falls between 30 and 50%. The risk of death from cancer or cirrhosis due to hepatitis B is approximately 25% if infection occurred in childhood.

Approximately 90% of healthy adults infected with hepatitis B will recover and be completely rid of the virus in six months.

Where hepatitis B is it most common?

It is endemic in China and in other parts of Asia where chronic carriers represent 8-10% of the adult population. Most of those infected were in childhood. There are also high rates of chronic infection in the Amazon and southern central and eastern Europe. In the Middle East and the Indian subcontinent, chronic carriers represent 2-5% of the population according to estimates. In Western Europe and North America, this proportion fell to less than 1%.

Transmission

Hepatitis B is transmitted through contact with blood or body fluids of an infected person (semen or vaginal secretions). The mode of transmission is the same as the human immunodeficiency virus (HIV), but hepatitis B is 50-100 times more infectious. Unlike HIV, it can survive for at least seven days outside the body. Throughout this period, it can cause infection if it enters the body of a person free.

The modes of transmission in developing countries are the following:

* Perinatal (from mother to child during birth)
* Infections in early childhood (asymptomatic infection due to close contact with infected relatives)

* Unsafe injections;
* Blood transfusions;
* Sex.

In many developed countries (Western Europe and North America for example), the modalities of transmission are different from those just mentioned. Today and in these countries, transmission occurs mainly in early adulthood, during sex or drug injection. The Hepatitis B is a major risk of infection of health workers.

The virus can be spread by water or contaminated food or by casual contact in the workplace.

The incubation period is 90 days on average, but ranges from 30-180 days. It can detect the virus 30-60 days after infection and persists in the body for periods that vary considerably.
Treatment

There is no specific treatment. Treatments aimed at maintaining patient comfort and nutritional balance, including replacement of fluids lost from vomiting and diarrhea.

It can treat chronic hepatitis B using drugs, including interferon and antiviral drugs are useful in some cases. Treatment can cost thousands of dollars per year and is not available for most patients in developing countries.

Liver cancer is almost always fatal, and often when patients are at their most productive stage of their lives and family responsibilities. In developing countries, most die within months after diagnosis. In high income countries, surgery and chemotherapy can prolong life for some years in some cases.

Patients with cirrhosis are sometimes given liver transplants, with varying success.
Prevention

He would administer the vaccine against hepatitis B to all infants: the basis for prevention.

It can be administered in three or four doses, as part of routine immunization schedules in force. In areas where there are frequently transmitted from mother to child, the first dose should be administered as soon as possible after birth (ie within 24 hours).

The complete vaccine induces protective antibody levels in more than 95% of infants, children and young adults. After the age of 40 years, the protection induced by primary vaccination drops below 90%. At 60 years, only 65-75% of those vaccinated a sufficient concentration of antibodies. Protection lasts at least 20 years and should continue throughout life.

It should vaccinate all children and adolescents under 18 who have not yet been. It should also be vaccinated persons belonging to groups at high risk as:

* People with risky sexual behavior;
* Partners and people living under the same roof as people infected with hepatitis B;
* Injecting drug users;
* People who need frequent transfusions or blood products;
* Recipients of organ transplants;
* Persons exposed to occupational hazards, including health personnel;
* Travelers visiting countries where there is a high rate of infection with hepatitis B.

The vaccine is extremely safe and effective. Since 1982, over one billion doses have been administered worldwide. In many countries where 8-15% of children become chronic carriers, vaccination has reduced this figure to less than 1%.

In December 2006, 164 countries vaccinate infants against hepatitis B as part of their national immunization programs, a substantial increase in coverage compared with 31 countries in 1992, when the World Health Assembly has adopted a resolution calling for vaccination against hepatitis B in the world.
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