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Six Plagues of Africa, Page 1 of 2
< Previous page Next page > /docserver/preview/fulltext/10.1128/9781555816483/9781555813567_Chap15-1.gif /docserver/preview/fulltext/10.1128/9781555816483/9781555813567_Chap15-2.gifAbstract:
One of the most deadly African diseases is sleeping sickness. It is undoubtedly of African origin and today remains indigenous to that region. Inoculation of blood containing trypanosomes into healthy animals produced surra. Trypanosoma gambiense gives rise to a mild chronic infection found in western and central Africa and is transmitted by riverine species of Glossina (G. palpalis and G. tachinoides) that are associated with human habitation. Asymptomatic individuals may harbor parasites in the blood for long periods of time and could be a source of infection for the vector. The disease is an anthroponosis: fly, to human, to fly, to human. T. rhodesiense is the East African form and is the more virulent subspecies, producing an acute infection. The spread of sleeping sickness was increased about 1890 because of another infection brought into Africa by cattle from outside the continent: rinderpest, a virus of cattle and game with high mortality. Treatment of sleeping sickness is of limited value and depends on early use of rather toxic drugs administered intravenously. Pentamidine, melarsopol, and suramin are all used. River blindness is transmitted by a blackfly called Simulium damnosum, which carries the microscopic infective juvenile stages (called microfilaria) of Onchocerca. The economic and social consequences of river blindness are profound, and surely much of the local history is tied to the progressive depletion of human resources.