on 19-Dec-2024 (Thu)

ΗBV genotypes have been associated with a risk of hepatocellular carcinoma (HCC) development and a response to interferon therapy.

НBV has been classified into 10 genotypes (A to J) based upon an intergroup divergence of 8 percent or more in the complete nucleotide sequence

Hepatitis B virus (HBV) infects more than 200 million people worldwide. It is the leading cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC), and these sequelae of chronic infection account for more than 800,000 deaths annually.

Hippocrates recognized the spread of jaundice by infectious agents as early as 4000 bc. Recently, the oldest known HBV was isolated from the mummified remains of a child discovered in the 16th century from Naples, Italy.1

The early modern cases of HBV infection were linked to the use of conventional viral vaccines, which were prepared from or contained human serum. In 1885 Lurman2 described the appearance of jaundice in 15% of 1289 shipyard workers who received smallpox vaccine prepared from human lymph

In the early part of the 20th century the increasing use of contaminated syringes and needles by diabet- ics on insulin and by patients treated for syphilis at venereal disease clinics elevated the importance of serum hepatitis.4,5 This led to the association of hepatitis B with blood and blood products, as well as to its distinction from infectious hepatitis, caused by hepatitis A virus, a member of the Picornaviridae family.6

The first hint of viral etiology came from the studies of Blumberg,7 who reported the discovery of a human antigen in Australian Aboriginals termed Australian (Au) antigen. Subsequently, the Au antigen came to be known as hepatitis B surface antigen (HBsAg), and its association with acute hepatitis was established

Due to their unique biologic and molecular characteristics, as well as their liver tropism, HBV and HBV-like animal viruses were given the status of a new family designated Hepadnaviridae (hepatotropic DNA viruses).

The primary host for HBV is human, but HBsAg has been detected in other primates, such as chimpanzees, gibbons, orangutans, African green monkeys, and squirrel monkeys

Thus a con- venient animal model for HBV remains unavailable; however, the discovery of the HBV receptor on hepatocytes has led to development of a more efficient tissue culture system that should facilitate new drug discovery

HBV was molecularly cloned from patients’ sera in 1979 and its complete DNA sequence determined.10–12

HBV, the human pathogen, and other mammalian hepatitis viruses with sequence homology and similar genome organization are grouped in the genus Orthohepadnavirus.