Disease Patterns Before A.D. 1000

The prevalence and distribution of diseases in sub- Saharan Africa have been determined by the natural environment, indigenous living patterns, and the interrelationships between African peoples and newcomers from other continents. The spread of agriculture since about 3000 B.C.; the extensive commercial contacts with the Moslem world from about A.D. 1000, and with Europe since the fifteenth century; and the establishment of colonial rule in the late nineteenth century - all have had important consequences for health conditions in Africa.

There is little evidence about the disease environment confronting Africans until fairly recent times. Literacy dates back to only about A.D. 1000, and then only in Ethiopia and some areas of the savanna zone just south of the Sahara desert. Written accounts of conditions on parts of the western and eastern coasts begin with the Portuguese voyages of the fifteenth and sixteenth centuries, but literary information on most of the vast interior is not available until well into the nineteenth century. Serious medical data collection really began with the colonial period, but even today knowledge of disease incidence and prevalence is far from adequate.

Africa south of the Sahara is a vast area with many different ecological zones. Besides the Sahara itself, there are extensive desert regions in the Horn of northeastern Africa, and the Kalahari in Namibia and Botswana in the southwestern part of the continent. Tropical rain forest prevails along most of the west coast, in the Zambezi valley of Mozambique, and in large areas of western equatorial Africa, including much of Gabon, Congo-Brazzaville, and northern Zaire. Forest, however, covers only about 10 percent of the land area.