Hepatitis A affects the liver and is usually spread through contaminated food and water or close physical contact with an infected person. It is common in developing countries where sanitary conditions are poor and the safety of drinking water is not adequately controlled. The disease can incubate for 3 - 5 weeks before illness develops. Adults can take many months to fully recover from infection whereas children often have very mild illness but can easily pass it to others. Hepatitis A is prevented by eating ’safe’ food, drinking ‘safe’ water and pre-travel vaccination.