Tsetse-flies are of great economic and pathological importance as the disseminators of tsetse-fly disease (nagana) and sleeping sickness.
Since, moreover, it is believed that at least five species of Glossina are carriers of nagana, it may well be that all tsetse-flies can disseminate both nagana and sleeping sickness.
Lugard little thought that in bringing these Sudanese, already (some of them) infected with the sleeping-sickness of the Congo forests, he was to introduce a disease which would kill off some 250,000 natives of Uganda in eight years.
A recent method of using the drug is in the form of sodium cacodylate by subcutaneous injection, and this preparation is said to be free from the cumulative effects sometimes arising after the prolonged use of the other forms. Other organic derivatives employed are sodium metharsenite and sodium anilarsenate or atoxyl; hypodermic injections of the latter have been used in the treatment of sleeping sickness.
The rate of mortality among the natives from tropical diseases is also high, one of the most fatal being that known as sleeping sickness.
