In a discussion of tropical diseases, we would be remiss if we did not discuss the colonial origins of medical research in this field. Tropical medicine was born out of both moral and economic imperatives, and further fueled by scientific motivations. Perhaps the best example of how colonialism drove tropical medicine is human African trypanosomiasis (HAT), or sleeping sickness. While today, sleeping sickness is categorized by the World Health Organization as a ‘neglected tropical disease’ (NTD), in the late 19th century the disease received considerable political and scientific attention because of its implications in the European colonization of Sub-Saharan Africa. The history of the fight against sleeping sickness is a clear portrayal of how Western motivations can advance, or neglect, disease research.
Sleeping sickness is transmitted by the bite of the tsetse fly, which transfers the parasite Trypanosoma brucei into the blood. In the early stages of infection, individuals will suffer from fever, headaches, joint pains and itching. The later stages of infection are characterized by the presence of parasites in the cerebrospinal fluid, and those afflicted begin to exhibit neurological symptoms such as confusion, disturbed sleeping patterns, sensory disturbances, extreme lethargy, and coma. Without treatment, this infection ultimately leads to death within months or years. HAT is typically caused by two subspecies of the parasite, T. brucei gambiense and T. brucei rhodesiense; however, a third subspecies, T. brucei brucei, also causes a severe and often fatal disease in domestic animals, which makes farming extremely difficult in areas infested with the tsetse fly. The disease currently threatens millions of people in 36 Sub-Saharan countries, particularly those in remote rural areas with limited access to medical treatment.
The earliest record of this disease comes from the 14th century Arab historian Ibn Khaldun. At the time, West African kingdoms such as Benin, Ghana, Mali, and Songhai were linked with the Arab world through trade routes. Ibn Khaldun reports the death of King Diata II of Mali, who suffered from “…the sleeping sickness, a disease that frequently afflicts the inhabitants of that climate.” Reports of the disease began to reach Europe in the 18th century through the accounts of slave ship doctors and medical officers in the slave trade. John Atkins, an English naval surgeon, published the first accurate medical report on African sleeping sickness in 1734. A century later, 13 European countries and the USA held “The Berlin Conference” to prevent conflict between rival imperialist powers during the “Scramble of Africa” – the occupation and colonization of the continent for its resources. Before the colonial era, Africans knew about the dangers of the tsetse flies and how to avoid them and their habitats. The subsequent invasion into the interior of Africa by European explorers and colonizers, however, led to a series of ecological and social disruptions resulting in severe outbreaks of the disease in Sub-Saharan Africa. Many people were forcibly relocated with no regard to the habitats of the tsetse flies, while new means of transport such as roads and railways increased the risk of transferring the parasite.
The first major epidemic of sleeping sickness began in 1896 and lasted until 1906, affecting populations mainly in modern-day Uganda and Kenya. The rapid spread of the disease and high death rates made imperial powers fear the impact it would have on the future administration and exploitation of their colonies. Officially, the motivation for colonial powers to respond to the epidemic was humanitarian, led by the rhetoric that the West was superior and had a moral imperative to help “lift” the native inhabitants out of disease. However, practical considerations were arguably the main drivers for campaigns against the disease. For one, the fight against sleeping sickness was a way to legitimize the European colonial presence. Competition between the colonial administrations of different European states motivated political and scientific support for the campaign against the disease. Sleeping sickness was also an economic problem; imperial powers feared that the disease would exacerbate manpower shortages, and domestic animals could not survive near fly infestations. There was also ample scientific motivation, as the field of microbiology was in its prime due to growing acceptance of the germ theory. In Great Britain, the London School of Hygiene and Tropical Medicine was closely tied to colonial administration. Tropical schools of medicine were established in Marseille, Brussels, and Amsterdam in the early 20th century, and the Pasteur Institute expanded overseas. Because eradicating sleeping sickness was considered to be highly important for the continued conquest of Africa, it attracted considerable scientific attention, funding, and publicity.
Each colonizing nation had its own distinct scientific culture and approach to the fight against the disease. In France, Louis Pasteur and Alphonse Laveran focused on identifying and eradicating the parasites, rather than the vectors of the disease. British scientists Ronald Ross, Patrick Manson, and David Bruce made advances on the role of vectors in disease transmission. In Germany, Robert Koch took a chemistry and pharmacological approach to killing the parasites using so-called “magic bullets” to kill specific pathogens. Despite these distinct approaches, international cooperation between scientists and physicians was highly important in disease control. Efforts to develop new treatments, vector and reservoir host control, game destruction, and especially the screening and treatment by systematic mobile teams led to the control of a second major epidemic that began in the 1920s and lasted until the late 1940s.
Despite differing styles of colonial rule and responses to epidemics of sleeping sickness in Sub-Saharan Africa, by the mid-1960s, there were fewer than 5000 cases reported on the whole continent. By the late 1960s, the majority of endemic countries had gained independence, but the legacies of colonialism resulted in political and social upheavals, which led to the weakening or abandonment of disease control programs. This was followed by a dramatic resurgence of the disease by the late 1980s, and the third major epidemic of the 20th century. By this time, sleeping sickness was a low priority for both the West and for the domestic powers within Africa combatting political and economic crises. By the end of the 1990s, rates of infection had almost reached the levels of the epidemics a century before. In 1995, the WHO estimated that though 60 million people were at risk of the disease, with an estimated 300,000 new cases per year, fewer than 30,000 were diagnosed and treated.
In 2001, the WHO launched a major disease-fighting initiative in partnership with pharmaceutical companies Aventis and Bayer HealthCare to provide drugs free of charge to endemic countries. Aventis’s drug, eflornithine, was initially developed as a cancer therapeutic, but was found to be ineffective and unprofitable and was dropped by Aventis in 1995. However, it was also an effective therapy against T. brucei gambiense. Whether due to Aventis’s proclaimed commitment to improving the quality of human life, or public pressure from Médecin Sans Frontières (MSF) and other global public health advocates, Aventis agreed to provide a long-term supply of eflornithine along with their sleeping sickness drugs pentamidine and melarosprol. Bayer also agreed to provide a free supply of the drug suramin, and MSF was commissioned for distribution.
The history of the fight against sleeping sickness is a clear portrayal of how Western motivations can advance, or neglect, disease research.”
Over the past 15 years, WHO-supported national control programs have resulted in record low cases. These programs included control of the vector and animal reservoirs, surveillance for active and passive case finding, diagnosis, and treatment and follow up. Between 2000 and 2012, the number of new cases reported dropped 73%, and by 2014 there were only 3796 cases recorded. The WHO’s partnership with Aventis (now Sanofi) and Bayer was renewed in 2016, and the disease could be eliminated by 2020 if progress is sustained.
The 20th century history of sleeping sickness delivers a clear example of how tropical disease and medical research can be directed not just by moral but also by political and economic imperatives of the powers that be. While there is no denying that the past actions of imperial powers wreaked havoc on the countries they occupied, the 21st century history of sleeping sickness is an uplifting example of how global collaboration between NGOs, international and domestic governments, and pharmaceutical giants can lead to the eradication of a once devastating disease.
- De Raadt, P. The History of Sleeping Sickness. Fourth International Cours on African Trypanosomoses October 2005. Retrieved from: http://www.who.int/trypanosomiasis_african/country/history/en/.
- Headrick, D. Sleeping Sickness Epidemics and Colonial Responses in East and Central Africa, 1900-1940. PLOS Neglected Tropical Diseases 2014; 8(4): e2772.