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Viral hepatitis
is the commonest liver disease in Bangladesh. About one crore
people in Bangladesh have been suffering from hepatitis B. A
proportion of them are hepatitis B carrier and another
proportion is affected by the long-standing consequences of this
infection. The treatment of hepatitis B possess a great
challenge. Enumerable authors working to find out cheap,
effective, efficient and easily administered drug therapy for
chronic hepatitis B (CHB).
The present paper highlights the recent advances in the
management of chronic hepatitis B and overview the pros and cons
of currently available drug therapy.
INTRODUCTION TO HEPATITIS B VIRUS
Hepatitis B virus (HBV) belongs to hepadnaviridae family which
primarily infects liver cells. The HBV genome is a relaxed
circular, partially double stranded DNA of approximately 3,200
base pairs.
The replication cycle of HBV begins with the attachment of the
virion to the hepatocyte. Inside the hepatocyte nucleus,
synthesis of the plus strand HBV DNA is completed and the viral
genome is converted into a covalently closed circular DNA (cccDNA).
The cccDNA is the template for the pregenomic RNA, which is
reverse transcribed into the minus strand HBV DNA. There are two
sources of cccDNA: entry of new virus particles into the
hepatocyte and translocation of newly synthesized HBV DNA from
the hepatocyte cytoplasm (Fig. 1). Most antiviral agents that
have been examined so far have little or no effect on cccDNA.1
This accounts for the rapid |
reappearance of
serum HBV DNA after cessation of antiviral therapy.
HBV is 100 times more infective than human immunodeficiency
virus (HIV). It is found in blood and body fluids and able to
survive in dried blood for longer than 1 week. It can be
transmitted by inoculation with contaminated blood or blood
products, by sexual contact, by transplantation of organs from
infected donors, by sharing contaminated needles, syringes,
razors, blades, tooth brush etc. and perinatally form infected
mothers. There is no evidence of viral transmission through
breast milk.2 In about one third cases, the underline mode of
transmission is not known.
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