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Scientists
isolated and sequenced the hepatitis C virus (HCV) genome
10 years ago. This led to the development of diagnostic tests
to identify people infected with HCV. Almost 4 million people
in the United States or 1.8 percent are persistently infected,
and the Institute of Medicine now includes hepatitis C virus
in its list of emerging infectious diseases. Those with the
greatest risk of infection are individuals who ever experimented
with injection drugs, even once or twice in the distant past,
had multiple sexual partners, or received blood or blood products,
for example, a transfusion prior to 1992. |
| The
Disease |
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HCV damages the liver, one of the body's most important organs.
Symptoms of both acute and chronic infections are easily confused
with less serious and shorter-term illnesses. In fact, most
infected people are relatively free of physical symptoms -
signs of liver damage may not occur for a couple of decades.
Unfortunately, by the time the disease becomes apparent, liver
damage can be considerable and even irreversible.
HCV
is not related to the other hepatitis viruses (A-E) and diagnostic
tests readily distinguish them. The virus is usually detected
by an antibody test. Unlike many other infections, the presence
of antibodies in the blood does not mean recovery. Although
rare, recovery does occur; it can be confirmed using highly
sensitive diagnostic tests that detect the viral genome (RNA).
Roughly
50 percent of chronic carriers do not even know they have
hepatitis C, a disease that moves through specific stages
of liver damage. Currently, diagnosis of the stage requires
a liver biopsy, i.e., removal of a very small piece of the
liver, and evaluation of an even smaller piece using a microscope.
The rate of progression is highly individual and can be characterized
as slow, medium or fast. For most people it is slow, i.e.,
after 20 years of chronic infection, only 20 percent of individuals
progress to cirrhosis. Alcohol and other hepatitis viruses
hasten progression of the disease. Thus, if they know they
are infected, individuals can help themselves by not using
alcohol, and by getting vaccinated to prevent hepatitis A
and B. |
| Treatments |
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The
Food and Drug Administration (FDA) has approved treatments
that can get rid of the virus and make the liver more normal.
Three are interferons and the fourth combines interferon and
ribavirin. Unfortunately, none of these drugs is very effective
(approximately 5 percent of infections are eradicated with
interferons and 35 percent with the combination) and all have
significant side effects. Currently, there is no way to predict
who will or won't respond. However, the best responses are
seen in those patients with HCV variants (genotypes) 2 and
3, less severe fibrosis, and who are female or are under the
age of 40 years. It is important to note that genotype 1,
which predominates in this country, is least responsive to
treatment. |
| Challenges
and Research Priorities |
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Better treatment and prevention strategies will come from
carefully designed, innovative, and cross-cutting research
studies that will help us learn why some people recover from
the infection and others do not; understand how the virus
reproduces and causes disease in the body; and develop more
effective and safer therapies as well as vaccines. |
| Importance
of Increasing Awareness |
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The fact that most people lack symptoms and may have been
infected years earlier, taken together with the drugs now
available to treat the disease, make it important for individuals
to report accurate personal histories to their physicians
so that detection and treatment of hepatitis C begins as early
as possible.
Hepatitis
C virus infection is an increasing public health concern.
Without more effective therapies that produce recovery, the
Centers for Disease Control and Prevention (CDC) predicts
that deaths due to HCV will double or triple in the next 15
to 20 years due simply to the length of time most people in
the United States have been infected. |
Useful
Information Sources: |
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Hepatitis
Foundation International
30
Sunrise Terrace
Cedar Grove, NJ 07009-1423
Tel: (800) 891-0707 or (201) 239-1035
www.hepfi.org
American Liver Foundation
75
Maiden Lane, Suite 603
New York, NY 10038
Tel: 1-800-GO LIVER (465-4837) or (201) 256-2550 |
NIAID,
a component of the National Institutes of Health, supports research
on AIDS, malaria, tuberculosis and other infectious diseases,
as well as allergies and immunology.
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