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Introduction

Hepatitis B Virus (HBV), original name Serum Hepatitis, is an inflammation of liver. Recently, there are about 350 millions of constant carriers (HBV) and more than 2 billion people are infected. The HBV is caused by the infectious disease commonly found in Africa and China. HBV could damage patient’s liver. If HBV is cured earlier, 90-95% of victims are able to fight off this virus and this virus will never be chronic. About 5-10% of victims will develop chronic infection.

There are 2 groups of Hepatitis B Virus:
1) Acute Hepatitis B, named fulminant hepatitis. There will be noticeable symptoms once someone is infected in a short time. Then, it will damage the infected person’s liver. Very soon, it may result in liver cancer and death.

2) Chronic Hepatitis B - The infected people may not know they are carrying the disease because the symptoms may not be appeared or noticed for years and their livers will work normally. It could pass from human to human. If this virus is not cured, severely it may result in liver cancer. If the infection is chronic, it can be never go away completely.


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Causes

When the virus is infected to the body, it will stay in the liver and start to damage the cells by replicating into more virus and messing up the function of the liver.

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Transmission

There are different ways to transmit HBV:
1) Infants infected at birth
* If the mother is a HBV carrier, the newborn baby may infected by his/her mother.
2) Bodily fluid
* If a HBV carrier’s bodily fluid (including blood) has contacted the wound or broken skin of a non-infected person, the non-infected person may be infected.

The below conditions will increase the risk:
- having sex with others
- injecting drugs with sharing needles
- transfusion of blood
- sharing razors or toothbrush



Symptoms

There will be many symptoms if you are getting HBV:
- loss of appetite
- Body aches
- Vomiting
- Fever
- Dark urine
- Itchy Skin
- Nausea
- Pain over liver
- Feeling tired
- Jaundice (the skin and the white part of the eye turning into yellowing)

If the patient is not being cured with this virus, it may result in:
- Metal disturbances (confusion, lethargy, extreme sleepiness, hallucinations
- Sudden collapse
- Jaundice
- Stomached

The acute HBV may last for 6 few weeks to 6 months; the chronic HBV may last for a very long time. The patients who have not been cured may result in liver disease fulminant hepatic failure: First, inflammation, next chronic cirrhosis (liver disease) for years, then liver cancer, finally death. Sometimes the symptoms (asymptomatic ones) may not be recognized.



Prevention

There are vaccines for the HBV prevention, as known as vaccine Antigenaemia, which is developed by Maurice Hilleman. It is developed for infants and adults and provides 85-90% of protection, predicted to last for 25 years.

The hepatitis B vaccine can prevent infection with HBV for at least 20 years and this is recommended for:
- Newborn babies
- Below and at 18 years old people who has not receive the vaccine before
- People inject drugs illegally
- People who have more than 1 sexual partner in 6 months or had sexually transmitted disease before.
- People having blood-clotting disorders

Besides vaccines, we can prevent HBV by:
- Not sharing needles, toothbrushes and razors
- Using plastic gloves when contacting blood.
- Not having too many sex partners
- Use condom when having sex


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Treatment

Most adults will clear the acute HBV infection spontaneously and fewer than 1% of patients cannot be treated. However, the treatment of chronic infection is necessary to decrease the chance of liver cancer.

Vaccines can stop the virus from spreading continuously, replicating the cells although no drugs are able to fight off the disease yet. There are 7 medications which is licensed in the United States for HBV:
- Antiviral drugs Iamivudine (Epivir)
- Adefovir (Hepsera)
- Tenofovir (Viread)
- Telbivudine (Tyzeka)
- Entecavir (Baraclude)
- Interferon alpha-2a
- PEGylated interferon alpha-2a (Pegasys)



Bibliography
Websites:
http://hk.knowledge.yahoo.com/question/question?qid=7008070801642
http://www.emedicinehealth.com/hepatitis_b/page2_em.htm
http://en.wikipedia.org/wiki/Duck_hepatitis_B_virus
http://en.wikipedia.org/wiki/Hepatitis_B#Pathogenesis
http://www.emedicinehealth.com/hepatitis_b/article_em.htm
http://www.emedicinehealth.com/hepatitis_b/page3_em.htm
http://www.webmd.com/hepatitis/hepb-guide/hepatitis-b-prevention

Rachel Cheung 9.2