Hepatitis B

 

Today, let’s discuss about Hepatitis B and its effects on the human body!

 

 

Firstly, what is Hepatitis B?

Hepatitis B refers to irritation and inflammation of the liver due to infection with the hepatitis B virus (HBV).

 

Hepatitis B Virus (HBV)

 

 

 

A little insight into the Hepatitis B virus:

 

· The Hepatitis B virus (HBV) is a member of the Hepadnavirus family.
Hepadnaviruses have very small genomes of partially double-stranded, partially single stranded circular DNA.

 

· It is classified as a Group VII virus.

· The genome consists of two uneven strands of DNA.
One has a negative-sense orientation, and the shorter strand has a positive-sense orientation.

 

 

 

How does the Hepatitis B virus cause irritation and inflammation of the liver?

1) Once the virus enters the body of a host, it infects liver cells.

 

2) Viral surface proteins fuses with the host cell membrane. Core particle enters the liver cell.

 

3) Viral DNA is brought into the nucleus and is repaired to form a covalently closed-circular form (cccDNA).

 

However, Viral DNA is not integrated into the host DNA like some viruses. Instead..

 

 

4) Once the DNA is recircularized, transcription of viral DNA and proteins begins.

 

5) DNA polymerase then begins copying the DNA. The polymerase protein uses its unique shape to initiate reverse transcription and copy the DNA. 

 

6)  Polymerase proteins bind in a stem-loop formation, which are packaged by in the golgi apparatus and secreted into the blood stream, where it can contact other liver cells and continue replication.

 

 

However, most of the damage from the hepatitis B virus occurs because of the way the body responds to the infection. When the body's immune system detects the infection, it sends out special cells to fight it off. However, these disease-fighting cells can lead to liver inflammation

 

How do people contract Hepatitis B?

Infection can be spread through:

• Blood transfusions
• Direct contact with blood in health care settings
• Sexual contact with an infected person
• Tattoo or acupuncture with unclean needles or instruments
• Shared needles during drug use
• Shared personal items (e.g toothbrushes and nail clippers) with an infected person
• From mother to child during childbirth.

 

How does it affect people living with this disease?

 There are two types of Hepatitis B, namely acute hepatitis and chronic hepatitis.

A hepatitis infection is considered to be acute during the first 6 months after being exposed.
If a person tests positive for the virus after 6 months, it is considered chronic hepatitis, which may last a lifetime.

 

The probability of developing chronic hepatitis depends on your age.

Adults- 90% will recover & 10% will develop chronic hepatitis.
Young children- 40% will recover & 60% will develop chronic hepatitis.
Infants- 10% will recover & 90% will develop chronic hepatitis.

 

Those living with chronic hepatitis usually do not exhibit any symptoms. However, some may develop cirrhosis or even liver cancer.

However, even if they do not exhibit any symptoms, they have some guidelines to follow to prevent the spread of the virus and to ensure that they live long and healthy lives.

• Keep all cuts covered and avoid sharing personal items.
• Those living in close contact with HBV infected persons should obtain the HBV vaccine.
• Avoid alcohol and smoking as it can be extremely harmful to the liver.
• Avoid eating raw shellfish, as it may contain harmful bacteria to your liver.
• Although most do not need to be on constant medication, they should visit a doctor familiar with Hepatitis B every 6 months.

 

 

What are the current cures for Hepatitis B?

Chronic hepatitis: No current cure. However, there are treatments available that slow down the virus. Those who develop cirrhosis or liver failure may need a liver transplant.
Acute hepatitis: No current cure. Treatments usually tackle the symptoms. However, most people can recover on their own.

 

What can we do to prevent being infected?

 

Hepatitis B vaccine is a vaccine developed for the prevention of hepatitis B virus infection.
It is believed to provide indefinite protection.

 

In conclusion, Hepatitis B is a fairly serious disease as it may cause cirrhosis or even liver failure. Thus, everyone should get the vaccine and limit the spread of HBV!

 

Signing off,

Illaisha!



Credits to the following websites!

• Retrieved from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001324/

1. Dienstag JL. Hepatitis B virus infection. N Engl J Med. 2008;359:1486-1500.
2. Perrillo R. Hepatitis B and D. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier;2010:chap 78.
3. Sorrell MF, Belongia EA, Costa J, Gareen IF, Grem JL, Inadomi JM, et al. National Institutes of Health Consensus Development Conference Statement: Management of hepatitis B. Ann Intern Med. 2009;150:104-10

Review Date: 11/23/2010.
Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

• Retrieved from http://www.bio.davidson.edu/people/sosarafova/Assets/Bio307/chbrough/page01.html

Bruss, V. & Ganem, D. 1991. The role of envelope proteins in hepatitis B virus assembly. Proceedings of the National Academy of Science USA 88:1059-1063.

Ocama, P., Opio, C., & Lee, W. 2005. Hepatitis B virus infection: Current status. The American Journal of Medicine. 118(12):1413-1420.

Rehermann, B. and Nascimbeni, M. 2005. “Immunology of hepatitis B virus and hepatitis C virus infection.” Immunology 5: 215-229

Christie Brough. Biology 307: Immunology. Dr. S. Sarafova. Davidson College. May 4, 2007

• Retrieved from http://www.ibibiobase.com/projects/hepatitis/hepatitis-aB.htm