Hepatitis A is an acute (short-term but quite severe) infection of the liver caused by the hepatitis A virus.
The hepatitis A virus can survive in the environment on hands for several hours and in food kept at room temperature for considerably longer and is relatively resistant to detergents. Hepatitis A occurs worldwide. In developing countries, most people are infected during childhood due to poor sanitation. With good sanitation and hygiene in the developed world, most people now reach adulthood without being exposed to hepatitis A virus.
In Australia, there are approximately 300–500 cases of hepatitis A reported per year. The number of cases reported has been declining nationally since the late 1990s (DoHA 2006). In 2011 there were 144 diagnosed cases of hepatitis A in Australia (Kirby Institute; 2012). The real number of hepatitis A infections is likely to be more than the number of infections reported. This is because many people with hepatitis A do not have obvious symptoms, do not go to the doctor and so are not tested for hepatitis A.
Up to 40% of people with hepatitis A have no identifiable risk factors for infection.