A supply of fuel ensures that a person can boil water and cook food. In many parts of the world, water taken directly from wells or public supplies contains waterborne parasites or other diseases and is not safe to drink. The water can be sterilized by boiling it, but fuel is needed to do so. Food is often unsafe or harder to digest unless it is cooked. Without enough fuelwood, many people suffer from disease and malnutrition. In places that lack infrastructure, the local water supply may be used not only for drinking and washing but also for sewage disposal. As a result, the water supply becomes a breeding ground for organisms that cause diseases such as dysentery, typhoid, and cholera.