Epidemiology Information

Moving on...

Epidemiology Information

The infelicity of HBV infection varies seriously worldwide. Infelicity of infection is considered high in those countries where achieved at least 8% of the population of HBsAg positive. In these countries, population with 70-90% got serological evidence of HBV infection. Most of the infection happened at early childhood and contributes to the high rates of HBV chronic infection in these populations.

HBV infection will continue after the first 5 years of life and bring to high risk, but it is a less significant contribution to the high rate of chronic infection. In most developed countries the frequency of chronic HBV infection is >1% and total infection rate is 5-7%. Most of the infections happened among high-risk adult populations that include abused drug users, persons who have multiple heterosexual partners, homosexual men, and health care workers. Although the percentage of babies and early childhood infections is low they still account for a unreasonably high rates of chronic HBV infections. For the other parts of the world have an transitional model of HBV infection.

The occurrence of HBsAg positivity ranges from 1-7%. There got some mixed patterns of infant, early childhood and adult transmission. Therefore, there is over 2 billion people have been infected by hepatitis B virus in all over the world. Survey found that people who died under chronic infection has reached a number of 360 million. On the other hand, over 600,000 of people die every year from HBV-related liver disease or hepatocellular carcinoma. All the Hepatitis B epidemiology and vaccines are focuses on best and powerful studies and highlights current trends, policies, and directions.

SOURCE:

Mahoney, Update on Diagnosis, Management and Prevention of Hepatitis B Virus Infection, Clinical Microbiology Reviews, 1999;

CDC, PATH High rates of HBV infection in sub-Saharan Africa, Southeast Asia, Eastern Mediterranean region, south and western Pacific islands, Amazon basin, and Caribbean.

please COMMENT... We need your input, insight, perspectives to increase our knowledge... *& marrkxx ;>

The HEPATITIS B VIRUS- biological characteristic, reservoir and transmission

Hello readers,


Its HUMAN HEPATITIS B VIRUS

This is the virus we got from sequencing the gene sample given by Mr. Cheong..

So...

We are going to First be Introduced to this very InTeResTing virus.. Keke

What Exactly Is This virus??

Biological Characteristic of Hepatitis B Virus (HBV)

Hepatitis B virus is a member of the family Hepadnaviridae, which includes woodchuck hepatitis virus, duck hepatits virus, and ground squirrel hepatitis virus.

HBV has a very small, circular DNA genome (3200 nucleotides) that is partially double-stranded and replicates through an RNA intermediate that is transcribed by a gene product with reverse trancriptase activity.

A notable feature of the virus is its efficient use of genetic information to encode four groups of proteins and their regulatory elements. This is achieved by shifting the reading frames over the same genetic material in order to encode distinct proteins within the same regions.
The 4 proteins encoded by HBV genome are the envelope, the nucleocapsid, the “X”, and a DNA polymerase.

HBV integrate DNA into host cells and they are oncogenic. HBV genome encodes 3 envelope proteins: pre-S1, pre-S2, and HBsAg is a glycosylated lipoprotein that contain the major site for binding of neutralizing antibody, designated the a determinant.

4 subtype epitopes have been identified: adw, ayw, adr, and ayr. Human appear to be the only natural host for HBV. HBV can produce a chronic infection, but the characteristics and determinants of virus persistence are not clearly defined except on an epidemiologic basis. Age at infection is the most important factor for determining the risk of chronic HBV infection.

The risk of chronic HBV infection for:

Newborns = 90%
Children below 5 years old = 30%
Older children, adolescents and adults = 2 – 10%
Male sex, Down’s syndrome or depressed cell-mediated immunity from drugs or infection =

higher risk

Feeling a little afraid and worried? ;p Now lets see how can you actually get INFECTED

Resevoir and transmission

It seems that the only known reservoir for Hepatitis B Virus (HBV) is human.

This virus is transmitted through broken skin (cuts) and/or mucosal contact with infectious blood or body fluids (e.g., blood, semen). The possible modes of transmission from an infected person are:

Sexual intercourse

Sharing of needles, syringes, or drug-preparation equipment

Blood contact through birth

Contact with blood or wounds

Sharing of personal and sharp objects such as razors or toothbrushes