How do the types of viral hepatitis differ from one another?
Hepatitis A: This is a very common infection occurring worldwide especially in areas of poor hygiene and sanitation. Large outbreaks of infection can occur. In England and Wales during 1991, over 7,000 cases were confirmed by laboratory tests although many more cases go undetected. The hepatitis A virus is excreted in the faeces of cases for about one week before and one week after their jaundice appears. The virus is transmitted by faecal-oral spread. The incubation period of the illness is between two and six weeks and the severity of infection varies with age; children often have no symptoms. Hepatitis A virus only very rarely causes chronic hepatitis. To help prevent spread of the infection, everyone should wash their hands thoroughly before meals, before preparing food and after using the toilet or changing nappies. People who live in the same household as a case of hepatitis A should be offered an injection of human normal immunoglobulin. Travellers to parts of the world where he
