Hepatitis B virus (HBV)

Published on January 31, 2017   32 min

A selection of talks on Gastroenterology & Nephrology

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Hello, my name is Dr. Marco Antonio Olivera Martinez. I am an Associate Professor of Medicine in the division of Gastroenterology & Hepatology at the University of Nebraska Medical Center in Omaha, Nebraska, United States. I am the Associate Program Director for the Transplant Hepatology Fellowship.
So what we're gonna talk about in this slide is the structure of the hepatitis B virus. This virus is known as being a DNA virus. This is the only hepatotropic virus that has DNA in its genetic material. It's known to be part of the family of the hepadnavirus group. The genome of this virus is approximately 3.2 kilobases and it has the ability to conform particle of DNA that is called cccDNA, ccc standing for circular, close, and covalent DNA. The peculiarity of this portion of genetic material is that the virus can insert it into the host's DNA and from there, its capability of producing break for replication once the patient develops immunity to this agent. There are eight known genotypes of the hepatitis B virus and they are classified A, B, C, D, E, and H. The antigens that we know that the virus produces are named s, e, and core. The s antigen is known as the surface antigen. And this is the first particle that is synthesized by the virus as it confers the protection in the surface of the variant, so the virus can go from cell to cell or be alive in the blood stream. The e and the core antigens are particularly present when the virus is actively replicating. From the epidemiological standpoint, 240 million people have chronic infection by hepatitis B in the world. Defining chronic hepatitis B as a presence of a positive surface antigen for more than six months according to the World Health Organization definition. And the prevention of this infection is carried out by a recombinant vaccine that is available worldwide.