Dr. Nick Crofts, head of the epidemiology unit at the Macfarlane Burnet Centre for Medical Research, Melbourne, says Hepatitis C is spreading more rapidly than any other serious disease.
Hepatitis C already causes 5 percent of all liver transplants and there are many more carriers of Hepatitis C than of HIV, the immuno-deficiency virus that causes AIDS.
Professor Richard Smallwood from the Heidelberg Repatriation Hospital, Melbourne, says that Hepatitis C “looks like becoming the disease of the decade”.
Hepatitis B and C viruses seem to be transmitted more easily than HIV.
The rapid spread of Hepatitis C in various communities has led to local fear and even hysteria in some areas because people are unsure about how it is spread. The people at greatest risk are those who have just been jailed (or who have completed sentences) and their partners.
Dr. Tony Stewart, of the Royal Children’s Hospital, Melbourne, says all adolescents should be considered at risk.
Hepatitis A is caused by a virus that is transmitted in food or water polluted by sewage.
If you travel in developing countries you run a risk of getting Hepatitis A from such contaminated food or water.
Swimming in the highly polluted Hong Kong harbor would give you a high risk of contracting Hepatitis A if you swallowed any of the water.
The Hepatitis A virus seems to be responsible for 70 percent of all cases of hepatitis.
Scientists using an electron microscope first identified it in 1973.
The Hepatitis A virus enters and destroys liver cells, producing an enlarged, tender liver and jaundice – a yellowing of the eyes and skin and the production of dark urine.
The liver sheds the virus into the bile so the virus enters the feces. Any fecal contamination will spread the virus although occasionally it may spread by close personal contact via saliva or blood.
Hepatitis A will make you feel distinctly unwell. Common symptoms are sore throat, nausea, fever and headache. You may develop jaundice.
In children, Hepatitis A causes severe upsets that resemble gastroenteritis.
The vaccine Havrix will protect for 5 to 10 years. Two injections of an inactivated virus are given four weeks apart, with a booster after 12 months.
Travelers to a developing country should be immunized. Young adults are particularly at risk since they may not have come into contact with the virus.
Vaccination of food-handlers would help stop the virus from spreading in the community.
In contrast to the Hepatitis A virus, the two main ways Hepatitis B are transmitted are unprotected sex (either heterosexual or homosexual) and by blood.
The virus spreads readily in blood in needles shared by self-injecting drug users and also by equipment used in tattooing and by the shared use of towels, toothbrushes or shaving gear.
There is no known risk factor in about one-third of cases.
Hepatitis B is a growing problem in Australia with about 3000 new cases every year and 1200 deaths because of liver failure. About 1 percent of the population carries the virus.
Professor Mark Harris, of the University of NSW, says GPs should be offering the Hepatitis B vaccine to early adolescents.
The United States and Britain are ahead of Australia as they propose to routinely immunize all babies against Hepatitis B and the World Health Organisation has recommended that all children should be immunized by 1997.
This approach is strongly supported by Dr. Sandra Thomson, from the Macfarlane Burnet Centre for Medical Research in Melbourne, who says that children should be protected against Hepatitis B as early as possible.
The younger a person is when infected with the virus, the greater the risk of becoming a carrier and of eventually suffering liver cancer. The overall chance for an infected adult developing serious liver damage is 1 percent, but it is 30 percent for infected infants.
For many years scientists thought there was another kind of hepatitis virus but it was not until 1988 that Hepatitis C was discovered.
Hepatitis C is transmitted in similar ways to Hepatitis B but seems to have a lower rate of transfer sexually and by needle-stick injuries.
Self-injecting drug users sharing needles probably account for 75 percent of all cases and unsterile tattooing, ear-piercing or acupuncture about 6 percent.
At the moment Hepatitis C is spreading in the community largely unchecked because of the prevalence of needle-sharing and the presence of large numbers of carriers.
Up to 90 percent of self-injecting drug-users have antibodies against Hepatitis C which indicates they have had the virus at some time.
Infection with the virus steadily increases with each year since the first self-injection but there is a high risk of infection with even only one unsafe injection.
It is possible that tiny amounts of blood in shared household items such as razors and toothbrushes also help transfer the virus.
If the virus enters your body it takes up to six months for your antibody level to rise sufficiently to be detectable so that people may have the virus and be infectious without knowing it.
Some people are able to eliminate the virus completely, but most (probably at least 80 percent) cannot and so become permanent carriers.
One reason seems to be that the virus does not induce the body to produce the chemical interferon, which normally destroys viruses.
The virus also constantly changes, so confusing the immune system. About half the people infected will have no symptoms. Others will be severely fatigued or will feel unwell and their liver will feel tender if examined.
Some people will develop the liver disease within a year. In others there are no symptoms for about 20 years until hepatitis eventually develops, usually involving cirrhosis of the liver and in about one-third of cases, liver cancer develops in another few years.
People who are hepatitis-positive should avoid alcohol to minimize damage to their liver and with Hepatitis B and C need to take particular care with bleeding cuts or scratches so as not to infect others.
A pregnant woman who is Hepatitis C positive is unlikely to pass the virus on to her baby (the risk is about 5 percent). The risk of passing on the virus in breast milk is also low so that women who wish to breastfeed should do so.