Trypanosomiasis Control in African History: An Evaded Issue?

Abstract

Social control of trypanosomiasis in African history deserves further study. The pioneering work in this field is John Ford's respected but neglectedThe Role of the Trypanosomiases in African Ecology(1971). While Ford's arguments have received support from recent findings in immunological, epidemiological and epizootiological research, they have rarely met with evaluation or engagement, either in historical or scientific literature. Historians have tended to describe trypanosomiasis control as a matter of avoiding contact with tsetse fly. In so doing they have implicitly rejected the position of Ford, who regarded infrequent contacts between tsetse and mammalian hosts as necessary for the maintenance of host resistance. Ford believed that host resistance, rather than avoidance of tsetse, was the basis of trypanosomiasis control. The historical nature of Ford's work requires that a satisfactory evaluation ofThe Role of the Trypanosomiasesmake use of historical, as well as scientific, data. The evidence of trypanosomiasis and cattle-keeping from one region of north-eastern Tanzania supports Ford and suggests that other explanations of trypanosomiasis control are inadequate. The Tanzanian evidence shows that precolonial societies coexisted with, but could not avoid, tsetse. They could not eradicate tsetse because scarcity of water prevented permanent occupation of large areas. Tsetse and trypanosomiasis did not prevent cattle-keeping, but helped to keep the region's cattle population low and confined it to relatively densely settled neighbourhoods. Social control of trypanosomiasis collapsed during the pre-Second World War period of colonial rule. Economic and political developments were primarily responsible for a series of famines between 1894 and 1934. Famine-induced depopulation allowed steady spread of tsetse and wildlife reservoirs of trypanosomes into formerly cultivated areas which had been free of tsetse before the colonial period.