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Prevalence Study Of Hepatitis B (australian Antigen) Among Patients
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CHAPTER ONE
INTRODUCTION
1.1 INTRODUCTION TO HEPATITIS B
Viral
hepatitis is a disease as old as the history of Medicine. Hepatitis was
described in the Babylonian Talmud in the fifty century BC, and was
referred to by Hippocratic over 2000 years ago. Despite this ancient
knowledge, it was not until 1963, that the first human Repetitious virus
was isolated, Hepatitis B. This was followed quickly by the
purification of Hepatitis A in 1973, and more recently by the isolation
of viruses C, D, E and G. These viruses are known to infect the human
liver (Anderson et al; 2001).
However, there are more than twenty
other viruses, which infect the human liver. These are not considered
“Repatitis viruses†as these other viruses tend to infect organs other
than the liver more seriously’. These include common viruses such as
Cytomegalovirus (CMV), Mumps, Rubella, Epstein-Barr virus (EBV) as well
as rare ones such as Rassa fever and yellow fever viruses.
Any
infection that results in inflammation of the liver is called Repatitis
(Greek Repaticus, liver). Incidentally, not all “hepatitis†is caused by
viruses. “HEPATITIS†means “inflammation of the liverâ€, and can be
caused also by other types of infection (bacteria fungi etc); toxic
drugs; poisons; alcoholism and so on (Drexott etal; 2005).
But of
interest is one Repatitis virus – one of the most common infections
diseases, causing an estimated 1.5millon deaths world wide each year –
Hepatitis B. Hepatitis B is caused by the Repatitis B virus (HBV), a
double – stranded circular DNA virus of complex structure. Hbv is class
ivied as an orthoropadnavirus within the family hepadnaviridae. HBV was
originally recognized as the age responsible or serum Repatitis the most
common form of partially transmitted viral Repatitis and an import
cause of acute and chronic infection of the liver. This why hepatitis b
is some times called seum Repatitis. The virus was formerly and anilines
referred to as Australian antigen. The reason being that it was first
isolated room the blood of an Australian aborogie and is associated with
HBV. (procott et al 2005.
Hepatitis B remain one of the major
cause of human suffering in the world despite a through understanding of
its transmission and prevention. Serum form undivided infected with
hepatitis B contains three district antigen particles: a spherical 22nm
particle, a 42 nm spherical particle ( counting DNA and DNA polymer
able) called the Dane particle, and tubular or filamentous particles
that vary in length. The small spherical and tubular particles are the
unassembled component of the Dane particle- the infective form of the
virus. The unassembled particles. Contain hepatitis B surface antigen
(HBsAg) whose presence in the blood is (a) an indicator of Repatitis B
infection (b) the basis for the large scale screening of blood for the
hepatitis B virus, and (c) the basis for the first vaccine for human use
developed by recombinant DNA technology (Evans, 1997
The
Hepatitis B virus is normally transmitted through blood transfusion,
contaminated equipment, drug users unsterile needles, or any body
secretion (saliva, soren, sweat, breast milk, urine) The virus also can
pass from the blood of an infected mother through the placenta to
infect the fetus. Each year an estimated 200, 000 people in Nigeria are
infected with Australian Antigen (HBV) about 1000 person die yearly
from hepatitis related cirrhosis and about 5000 die from HBV related
liver cancer. (HBV is second only to tobacco as a known cause of rumen
cancer). Worldwide, HBV infects over 200 million people (Schlesinger
& Schlesinger, 2001). The clinccal signs of Repatitis B vary widely,
most cases are symptomless. However, sometime fever, loss of appetite,
abominal discomfort, nausea, fatigue, and other symptoms gradually
appear following an incubation period of 1 to 3 months. The virus
infects liver Hepatic cells and causes liver tissue degeneration and the
release of liver associated enzymes (transaminases) into the blood
team. This is followed by jaundice, the accumulation of bilirubin (a
breakdown product of raemoglobin in the skin and other tissue with a
resulting yellow appears. The distinctive yellow jaundice the Hepatitis B
usually imparts to its victims skin has made it an rasity detectable
disease through recorded history. Frequently, acute hepatitis B in
anicteric and symptomatic, although acute liver failure may develop. The
virus persists in about 10 percent of infected immouno compent adults,
and in as many 90 percent of infants infect peninatally depending on the
ethnic group of the mother. About 350 million people worldwide are
persistent carries of hepatitis B. actually one in twenty infection
results in chronic hepatitis, defined as persistent hepatitis virus six
mouths after the onset of the acute illness. Chronic HBV infection can
be entirely begin with normal liver blood tests (“Chronic Carrier
Stateâ€) or may be an aggressive inflammatory process (“Chronic active
hepatitisâ€), which can lead to severe scarring (“Cirrhosis).
Approximately
25 percent of all patients with chronic hepatitis will progress to
cirrhosis and about 20 percent of those with cirrhosis will develop
hepatocellular carcinoma. That is to say, the risk of liver cancer
(hepatoma) is high in cirrhosis caused by HBV.
Hepatocellular carcinoma is one of the most common cancers worldwide (Seeger & manor; 2000)
During
the first phase of chronicity, virus replication continues in the liver
and replicative intermediates of the viral genome may be detected in
DNA extracted from liver hiopsies. Makers of virus replication in serum
include HBVDNA (this indicated virus presence and activity), DNA
polymerize (determines the presence of HBVDNA in liver cell, and a
soluble antigen, hepatition.be antigen (\HbeAG), which is secreted by
productively infected hepatocytes. In those infected at a very going age
this phase may persist for life but, more usually, virus levels decline
over time. Eventually, in most individuals, there is immune clearance
of infected hepatocytes associated with seroconverision low replication,
the viral senome may integrate into the chromosomal DNA of some
hepatocytes and these cells may persist and expand closely. Rarely ,
seroconversion to anti-HBs follows clearance of virus replication but,
more frequently, HBSAg persists during a second phase of chronicity as a
result of the expression of integrated viral DNA.
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ABSRACT - [ Total Page(s): 1 ]The prevalence of viral hepatitis B among patients in National Orthopedic Hospital Enugu was studied. The samples comprised that of men , woman and children 200 in numbers, all patient of orthopedic Hospital Enugu. Laboratory investigation done were this HBs tested which 110 patient out of the 200 patients tested positive, and liver function tests found abnormal in almost all the patients that tested positive to HBsAG routine test. The commonest clinical presentations were fever and jaundice ... Continue reading---
