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Some helpful definitions of terms used
+ ALT Alanine aminotransferase - a protein which, when found in the blood in elevated quantities, generally indicates liver damage. |
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+ Antibody A protein secreted by cells of our immune system in response to infection. The antibody binds to an 'enemy' molecule, in this case, a specific part of the hepatitis C virus. This is meant to prevent the virus from infecting other cells or destroy it. As with other viral infections, the presence of antibodies does not necessarily mean a virus will be eliminated from the body. |
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+ Antigen Anything introduced into the body that is seen as foreign. An antigen stimulates the immune system into producing cells that attack it. |
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+ AST Aspartate aminotransferase - a protein which, when found in the blood in elevated quantities, generally indicates liver damage (although less specific for liver damage than ALT). |
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+ Asymptomatic Having no symptoms. |
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+ Blood & Blood products Components of blood including red cells, platelets and plasma which are separated out by blood banks. Plasma is processed and purified to produce specific medical purposes, eg. Factor VIII. |
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+ Carrier Practically all people who are HCV antibody positive 'carry' the virus. The term 'carrier' is often misused, though, to mean someone who has the hepatitis C virus yet is in good health. In regard to hepatitis C, the term 'carrier' is used less and less. Better definitions of illness status include antibody positive or antibody negative; symptomatic or asymptomatic. Most important to note, is that all people who are hepatitis C antibody positive need to be aware of potentially passing on the virus. |
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+ Chronic Active Hepatitis Any form of liver inflammation lasting more than six months and causing continuing damage to liver cells. It often precedes cirrhosis. |
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+ Chronic Persistent Hepatitis A mild form of chronic hepatitis, usually associated with a better outcome. In hepatitis C, the distinction between chronic active and chronic persistent hepatitis is not so clear cut. |
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+ Cirrhosis A condition where scar tissue develops in the liver - to the extent where such scaring becomes extensive and permanent. Cirrhosis interferes with the normal functioning of the liver. |
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+ DNA The genetic material which determines a cell's activities. It carries the cell's genetic code. |
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+ Fibrosis Scar formation resulting from the repair of tissue damage. If it occurs extensively in the liver, it is called cirrhosis. |
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+ First generation hepatitis C antibody tests These were the first tests developed (in 1990) to detect hepatitis C antibodies - our body's response to the virus. The test searches for a limited number of 'signs' of the antibody, such as the way its shell or envelope is made. These tests have been superseded by newer generation tests with improved sensitivity and specificity. |
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+ Genotype Different genotypes of the one virus are similar enough to be regarded as the same type but have some minor differences in their RNA composition. These differences may mean the virus reacts differently to our immune response or to drug treatments and natural therapies. |
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+ Hepatocellular carcinoma Cancer of the liver. A malignant tumour arising in the liver. In most cases, it occurs as a complication following cirrhosis. |
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+ Mutate When cells divide or viruses multiply, their genetic material must be copied. Sometimes mistakes are made when this happens and the resulting new cell or virus is different in some way. This is important for viruses because mutation can fool the immune system into not recognising the virus. |
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+ Non-A non-B hepatitis The old term for hepatitis shown not to be caused by the A&B viruses. In 1988, this form of hepatitis was shown to be mainly caused by HCV. |
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+ Prevalence In regard to hepatitis C, prevalence relates to the number of cases in the community at any one time. It is usually expressed as a percentage or ratio. eg. 1% of the population, or 1 in 100 people. |
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+ Pathogen Any organism or substance capable of producing a disease. |
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+ PCR PCR (polymerase chain reaction) is a process used to amplify pieces of the genetic make-up of a cell or virus. The amplified pieces are then detected and the presence of the virus itself can be determined. |
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RNA RNA is a genetic material similar to DNA. It often acts as a 'message' that is delivered to cells, prompting them to change and prepare for reproduction. |
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Second
generation hepatitis C antibody tests These were developed after 1992 and search for more specific 'signs' of the hepatitis C virus. Because these tests identify more parts of the antibody, they are more sensitive and specific than the original first generation tests. |
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+ Viral load The amount of virus present in a person's blood stream. It is usually measured by the PCR quantitative test and the result is given in number of virus particles per ml of blood. |
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+ Virus A vast group
of minute structures, composed of a sheath of protein encasing a core
of nucleic acids which are the building blocks of RNA and DNA. They
are capable of infecting almost all members of the animal and plant
kingdoms, including bacteria. Viruses are characterised by being total
dependent on living host cells for their reproduction. |