When did we relate tsetse to trypanosomiasis?

African cattle owners learned long ago from experience, that there was a link between biting flies and the spread of trypanosomiasis or nagana in their stock. The link between the tsetse fly and trypanosomiasis was first formally established by David Bruce working in what is now KwaZulu-Natal, South Africa.

Sleeping sickness
Some of the earliest descriptions of sleeping sickness come from what is now Mali. Travellers recognized the symptoms of the disease but were not aware of its link with tsetse flies. Aldo Castellani is credited with formally identifying trypanosomes as the cause of sleeping sickness (Castellani, 1903).

Trout and trypanosomes
The first description of a trypanosome was made by Gabriel Valentin from the University of Bern in Switzerland. He observed an organism in the blood of a trout and published his observations in 1841. To this day, many tsetse entomologists retain an interest in trout.


Bruce, D. (1896). Further report on the tsetse fly disease or nagani in Zululand. Harrision and Sons, London

Bruce, D., Hamerton, A.E., Bateman, H.R. & Mackie, F.P. (1909). The development of Trypanosoma gambiense in Glossina palpalis. Proceedings of the Royal Society (series B) 81, 405-414.

Castellani, A. (1903). On the discovery of a species of Trypanosoma in the cerebrospinal fluid of cases of sleeping sickness. Proceedings of the Royal Society 71, 501-508.