Tropical diseases are also widespread, including malaria, sleeping sickness, leprosy, and diseases of parasitic origin. Common illnesses also include pneumonia, poliomyelitis, tuberculosis, and venereal diseases.
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.