Hepatitis A

Hepatitis A is the inflammation of the liver from the hepatitis A virus. Compared to Hepatitis B and C,
Hepatitis A is the least serious and mildest of these diseases because Hepatitis B and C may become chronic illnesses but Hepatitis A will not.                          

A brief introduction of the Hepatitis A virus (HAV)..

• Group IV Virus
• Positive-sense ssRNA virus
• Belongs to the Picornaviridae family
  - Non-enveloped
  - Contains positive single-stranded RNA packed in a icosahedral capsid  
  What are the symptoms of Hepatitis A?
  Symptoms will normally appear 2 to 6 weeks after the initial infection. These symptoms are mild and may last for a few months for adult sufferers but children sufferers may not show these symptoms at all. Symptoms usually subside after 2 months, but in severe cases, the person may be sick for as long as 6 months.
  

   Symptoms include :

  
  • Fatigue
  • Fever
  • Abdominal pain
  • Nausea
  • Loss of appetite
  • Jaundice (yellowing of the skin or whites of the eyes)
  • Dark urine (Bile is removed from bloodstream and excreted in urine)
  • Pale or clay-colored stools
    
    
    

  What causes a person to be infected with HAV?
  

  • Eating food or drinkingwater that has been contaminated by stools (faeces) containing the hepatitis A virus (fruits, vegetables, shellfish, ice, and water are common sources of HAV)
  • Ingestion of shellfish reared in polluted water
  • Coming into contact with an infected person's blood or stools
  • A person infected with HAV does not wash his or her hands properly after going to the bathroom and touches other objects or food
  • Participating in sexual practices that involve oral-anal contact

  
  Any treatment available for sufferers?
  There are currently no specific treatment for Hepatitis A. Sufferers are advised to have plenty of rest, eat a well-balanced diet, stay hydrated and avoid alcohol and fatty foods as these may be poorly tolerated by the body and may induce vomiting.
  
  However, Hepatitis A vaccine is available to protect a person against Hepatitis A but not from other kinds of hepatitis. A person should be protected against the disease within 2 - 4 weeks after getting the first dose. After receiving the first vaccination, children and adults should have a booster vaccination in 6 to 12 months. A vaccine called Twinrix protects adults against both hepatitis A and B and it is given in three doses. Hepatitis A vaccination is recommended for all children older than age 1.
  
  
  How to reduce the risk of contracting or spreading the virus?
  

  • Always wash your hands thoroughly after using the restroom and when you come in contact with an infected person's blood, stools, or other bodily fluid.
  • Avoid unclean food and water.

  
  
  To reduce the spread of HAV, let's all take a more proactive stand to practice proper hand washing and if you have yet to get the vaccination, be sure to do so as soon as possible!
  
  
  

  Jayme.

  
  
  References :
  

  • Retrieved from : http://en.wikipedia.org/wiki/Hepatitis_A
    

  • Retrieved from : http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001323/ 

  1. Advisory Committee for Immunization Practices (ACIP) Centers for Disease Control and Prevention (CDC). Recommended immunization schedules for children, adolescents, and adults -- United States, 2010 (accessed November 9, 2010).
  2. Advisory Committee for Immunization Practices (ACIP) Centers for Disease Control and Prevention (CDC) Update: Prevention of hepatitis A after exposure to hepatitis A virus and in international travelers. Updated recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep. 2007;56:1080-1084.
  3. Hoofnagle JH. Acute viral hepatitis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 151.
  4. Sjogren MH, Cheatham JG. Hepatitis A. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 77.
  5. Victor JC, Monto AS, Surdina TY, Suleimenova SZ, Vaughan G, Nainan OV, Favorov MO, Margolis HS, Bell BP. Hepatitis A vaccine versus immune globulin for postexposure prophylaxis. N Engl J Med. 2007;357:1685-1694.

  
  

  Review Date: 10/16/2011.

  
  

  Reviewed by: David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. and George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California.

  
  

  • Retrieved from : http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004427/ 

  1. Centers for Disease Control and Prevention. 2012 immunization schedules for children 0 to 18 years of age. October 25, 2011.
  2. Centers for Disease Control and Prevention. Recommended adult immunization schedule. United States. 2011 Proposed Revisions, Advisory Committee on Immunization Practices. October 28, 2010.

  
  

  Review Date: 10/16/2011.

  
  

  Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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

Blood-borne diseases

Hey guys, Jayme and Illaisha here! For our MBC project, we will be focusing on Blood-borne diseases, specifically Hepatitis. Stay tuned to find out more about this intriguing disease!

Signing off,

Illaisha!