Sleeping Sickness Epidemics and Colonial Responses in East and Central Africa, 1900–1940

Human African trypanosomiasis, better known as sleeping sickness, nowadays ranks among the more neglected diseases in the countries of Africa where it is found. Though it still kills many people every year, it cannot compete for celebrity with such major killers as malaria and AIDS. Yet that was not always the case. A hundred years ago, sleeping sickness attracted considerable scientific research and political attention because of its importance to the conquest of sub-Saharan Africa by the European colonial powers. The goal of this paper is to describe the nature of the sleeping sickness epidemics that afflicted East and Central Africa in the early 20th century, the efforts made by European scientists to understand the disease and find means of controlling it, and the differences between the methods used by the British, Belgian, French, German, and Portuguese colonial authorities to combat it. Sleeping sickness is a parasitic disease transmitted by tsetse flies. An infected person has joint pain, headaches, and a fever, then becomes drowsy. The infection also causes a swelling of the lymph nodes at the back of the neck. Once the pathogen crosses the blood-brain barrier and infects the central nervous system, the patient becomes lethargic or insane, then goes into a coma, and finally dies. There are two varieties of sleeping sickness, and they affect their victims very differently. One, caused by the protozoan Trypanosoma brucei gambiense, is a chronic disease that can persist for months or even years with occasional mild symptoms before it enters the central nervous system. The other, caused by T. b. rhodesiense, is acute and can cause death within three to 12 months of infection [1–3]. Africans were well aware that a closely related disease, animal trypanosomiasis, or nagana, caused fever and a progressive deterioration in the health of livestock, especially cattle. They knew it was transmitted by tsetse flies; in some areas they called them ‘‘canoe flies’’ because they were found near rivers or ‘‘elephant flies’’ because of their size. Cattle herders in East Africa avoided tsetse-infested areas or set fire to bush in order to clear areas of flies and of wart-hogs, bush-pigs, and other wild animals whose blood the flies fed on [4–6]. Sleeping sickness was endemic in many parts of Africa, with occasional epidemics, long before the colonial era. In the 14th century, the Arab historian Ibn Khaldun wrote that King Diata II of Mali had died of it. It was known to Europeans along the West African coast in the 18th century and in West Africa and the lower Congo in the 19th. According to John Ford, a specialist in the tsetse fly problem writing in the 1960s, Africans before the colonial era had established a rough equilibrium between two ecosystems, the human and domestic on the one hand, and the natural and wild on the other. Africans, whose ancestors had lived on that continent for hundreds of thousands (if not millions) of years, knew the habitats of tsetse flies and how to avoid them. This equilibrium was shattered by the invading Europeans, causing a series of ecological crises, including famines and epidemics of rinderpest, sleeping sickness, jiggers, and others [5,7].