Sleeping sickness pandemics, 1880-1929

The history of tsetse control reflects the history of tropical medicine in East Africa.19 During the late nineteenth and early twentieth century, the epidemic of sleeping sickness killed an estimated 300,000 to 500,000 people in the Congo Basin, in Busoga in Uganda, and in Kenya.20 The epicenter of the disease was the kingdom of Bunyoro Kitara (in Uganda), from where the pandemic spread to neighboring regions. Bunyoro Kitara became empty of human habitation and became a wilderness.21 According to Endfield and colleagues,22 the colonial disruptions of populations, tribal warfare and the earlier slave trade had prepared the ground for such outbreaks of sleeping sickness. Moreover, the culmination of the rinderpest cattle epidemics in the late nineteenth century had concentrated populations in smaller areas and exposed them to tsetse flies.

By the 1890s, when environmental management had collapsed, farming communities lost the ability to control the tsetse flies.25 The abandoned grazing and agricultural lands became bushlands—further ideal habitats for tsetse flies.24 The British Royal Society appointed a committee in 1896 to assist the colonial governments with scientific investigations. Lord Lister, the President of the Royal Society requested the Tsetse Committee for information on the distribution of the fly in the British East African colonies.2’ The survey showed that in the Protectorate of Uganda, more than 25 percent of the total population had died of sleeping sickness; and in the region of central Tanganyika bordering the Lake Victoria Basin, huge numbers of the population had either died or been infected by sleeping sickness.26

The focus was on the regions bordering the Lake Basin, where sleeping sickness pandemics resulted in high human fatalities in 1900.2' The most severe outbreaks were in 1902, when the Royal Society Commission sent a medical team to investigate the pandemic.28 By 1903, the infestation across East Africa had worsened with an estimated 90,000 deaths in Uganda alone.29 By 1904, the Royal African Society had estimated that an additional 40,000 people had died in Uganda. Consequently, Sir Michael Foster, the Secretary of the Royal Society, recommended medical research on a large scale to keep the British government well-informed about the pandemic in the East African colonies’0 (discussed in the following subsection).

Between 1900 and 1904, along the Lake Victoria littoral, over 200,000 people had died of the disease, which was 90 percent of the total human population.’1 The areas abandoned by human populations became subject to bush encroachment, thus expanding the habitats of the tsetse flies. An estimated 90 percent of the grazing lands were infested, rendering large areas uninhabitable.’2 From local sources, such as Chief Elija Bonyo living on the Kenyan side of the lake, the sleeping sickness pandemics had reduced the human populations along the lakeshore, forcing survivors to flee to Tanganyika.55 From the Ugandan side of the lake, the flies had been transported by boats and infested the islands in the lake that experienced epidemics of sleeping sickness in 1903 and 1904. Busoga Island was depop- ulated by sleeping sickness, and populations were displaced from other islands.54 From the islands, the tsetse spread to the marshes along the lake shores and then on to the adjoining dry lands on the Kenyan side of Lake Victoria, extending further inland.”

By 1905 there were reports of deaths of cattle,36 and by 1907 the cattle population in the infested areas in Uganda along the shores of Lake Victoria had been removed.3' In southern Ankole, cattle died in large numbers in 1909 from a variant of the trypanosome (Trypanosomea Congolese), with mortalities reaching 75 to 80 percent by 1910. On the Kenyan side of the lake, the epidemics had terminated by 1911 when the Provincial Commissioner reported the problem as ‘slight.’38 In Uganda, the cattle populations in Ankole and the southwestern districts were on the path of recovery from 1912, before collapsing again. The disease had by 1913 forced the population into the German East African territory.’9 The demographic collapse caused environmental ripple effects, favoring further expansion of tsetse fly.40

Following the British military invasion of the German East African territory in 1914-1915, Ankole was re-infested by tsetse flies which were introduced along with the military and civilian traffic. Vast herds of the ration cattle and horses died of the trypanosomiasis.4I In other regions of East Africa, the tsetse fly threat to cattle and people remained widespread. By 1916, the fly was reported in the Kedipo Valley bordering South Sudan, and in the Dodoth country in northeastern Uganda. The expansion of the flies changed the grazing patterns of the Dodoth herds by concentrating people and livestock in the remaining tsetse-free areas.42 The period was quickly followed by the complete collapse of the cattle population between 1919 and 1920 that forced the Ugandan colonial government to again seek measures to halt the expansion of the tsetse fly.43

In the Sukumaland in Tanganyika, rapid expansion of the tsetse was responsible for the deaths of some 20,000 people between 1912 and 1921. Populations were again displaced44 and by 1918, the fly was expanding in central and East Africa at the rate of 1,609 km2 per annum, thus overrunning the region.4’ By 1920 and 1921, sleeping sickness resurgence was reported on the islands on the Kenyan side of the lake and along the Lake Victoria coastal littoral. However, it was not until 1924 that a survey was conducted on the Kenyan side of the lake to provide a better overview of the distribution of tsetse flies. The survey found very low human populations in the region. The survivors reported that prior to the earlier pandemic, the areas had been densely settled by farming communities.46 Clearly, tsetse fly research and control had become urgent.4'

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