HepatitisHepatitis A is a virus from the picorna virus family which is spread by the faecal-oral route, and can be contracted from shellfish caught in water contaminated by infected sewage. A person infected by hepatitis A will be secreting the virus for two weeks before the onset of jaundice, which is usually the first sign of the illness. While the disease can be very debilitating complications are rare. There is no treatment available, other than maintaining adequate fluid and caloric intake with avoidance of fats and abstinence from alcohol together with rest, and complete recovery is the rule. Sometimes there may be prolonged jaundice and itching, which may be helped by a short course of steroids. There is an effective vaccine available which should be used by anybody travelling to an area affected by the disease. Hepatitis B is caused by a virus that has DNA as its genetic material. It is transmitted parenterally (parenteral means by any route other than orally - which is why it used to be called serum hepatitis). It may be contracted from transfusion of infected blood, by injection from an infected needle - for example during tattooing or body piercing, by unprotected sexual intercourse with an infected partner or to a baby born to an infected mother. Unlike hepatitis A this can be a devastating illness causing fulminant hepatic failure, chronic hepatitis or cancer of the liver. Like hepatitis A there is an effective vaccine available which should be taken up by travellers to countries where the disease is widespread, and by people who may be exposed to the risk of infection such as health workers. (Immunity to hepatitis B is a prerequisite for medical students in the UK). Hepatitis C was not identified until 1988; previously this was known as Non-A Non-B hepatitis. Like hepatitis B this is transmitted parenterally. It is caused by a small virus from the flavo virus family, and while it occurs throughout the world it is particularly prominent in the Middle East, where up to 14 per cent of the population may be infected. It causes a chronic disease which may lead to cirrhosis of the liver and liver cancer. While there is no vaccination available to prevent infection, treatment using an anti-viral drug called ribavirin together with injections of the agent interferon alpha may prevent the progression of the disease. Hepatitis D - also known as hepatitis delta - is caused by infection with a small virus that only affects patients who already have hepatitis B, so that vaccination against hepatitis B also confers immunity to hepatitis D. Hepatitis E is, like hepatitis A, transmitted by the faecal-oral route. It is widespread in the developing world, particularly in areas of poor sanitation. There is neither treatment nor vaccination available so avoidance of infection depends upon good hygiene on the part of the traveller. While recovery is normally the rule it can prove fatal to women in the later stages of pregnancy. The liver may also be affected by other viruses such as the Epstein Barr virus which causes glandular fever, or infectious mononucleosis, and cytomegalovirus - another member of the herpes virus family. Besides being caused by infection by a virus, hepatitis may occur as a result of excessive alcohol intake, or sensitivity to any one of a wide range of drugs or medications. |
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