Disease carrier Scottish missionary and explorer
David Livingstone was the first to suggest that sleeping sickness in animals was transmitted by the bite of
tsetse fly. His 1852 report mentioned that cattle he used in the valleys of the
Limpopo River and
Zambezi River and at the banks of the
Lake Malawi and
Lake Tanganyika had sleeping sickness after exposure to tsetse flies. saying:[The] animal continues to graze, emaciation commences, accompanied with a peculiar flaccidity of the muscles, and this proceeds unchecked until, perhaps months afterward, purging comes on, and the animal, no longer able to graze, perishes in a state of extreme exhaustion. Those which are in good condition often perish soon after the bite is inflicted with staggering and blindness, as if the brain were affected by it... These symptoms seem to indicate what is probably the cause, a poison in the blood, the germ of which enters when the proboscis is inserted to draw blood. The poison-germ, contained in a bulb at the root of the proboscis, seems capable, although very minute in quantity, of reproducing itself, for the blood after death by tsetse is very small in quantity, and scarcely stains the hands in dissection.Livingstone further made experiments to cure infection in horses using arsenic as he reported in
The British Medical Journal in 1858.
Animal sleeping sickness Scottish physician David Bruce, while working in the
Royal Army Medical Corps stationed at
Pietermaritzburg, Natal, South Africa, was assigned to investigate nagana which severely struck cattle and horses in
Zululand. On 27 October 1894, he and his wife Mary Elizabeth Bruce (
née Steele), who was also a microbiologist, moved to Ubombo Hill, where the disease was most prevalent. He discovered protozoan parasites from the blood of infected animals. It was the discovery of
Trypanosoma brucei, the name created by
Henry George Plimmer and
John Rose Bradford in 1899 in honour of the discoverer. The genus
Trypanosoma was created by Hungarian physician David Gruby in his description of
T. sanguinis, a species he discovered from the blood of frogs in 1843. How the infection was transmitted in animals and its relation to human sleeping sickness were not known.
The first human trypanosome On 10 May 1901, an English steamboat captain was admitted to a hospital at Bathurst, Gambia, due to high fever. British Colonial Surgeon Robert Michael Forde examined the blood samples and identified some organisms which he attributed as parasitic worms. After recovery, the same person was admitted to the same hospital again in December 1901. Forde asked
Joseph Everett Dutton, a parasitologist on expedition who was visiting the hospital at that time. Forde described the causative infection as "very many actively moving worm-like bodies whose nature he was unable to ascertain" from his original diagnosis to Dutton. Dutton prepared several blood smears from which he concluded that the parasites were protozoans belonging to the genus
Trypanosoma, yet distinct in structure and disease it caused from those of known species at the time. In his report in 1902, he made a concluding suggestion:At present then it is impossible to decide definitely as to the species, but if on further study it should be found to differ from other disease-producing trypanosomes I would suggest that it be called
Trypanosoma gambiense. == The Commission ==