Malaria is the greatest single cause of illness and death. Children are commonly afflicted by malaria, and many die of it in their first two years of life. Bilharzia ranks second to malaria. It is transmitted by contaminated water. Transmission of pneumonia, usually by contact, is also a serious health problem, especially in areas of high population density.
Nutritional disorders are also a common cause of death, especially in children.
Unsanitary conditions and crowded, unventilated houses aggravate these problems. Food stored in the open air is exposed to contamination by dust and flies. Few towns have adequate sewage systems. Water, especially in rural areas, is subject to contamination. Water polluted with human and animal waste is frequently found being used for laundering, bathing, and even drinking.