The investigation of Trypanosoma brucei isolates obtained from Glossina pallidipes in South Nyanza, Kenya.

During studies to determine the main Trypanosoma brucei rhodesiense transmission sites in Lambwe Valley, Western Kenya, Glossina pallidipes were collected from two areas in the valley and examined for trypanosome infection. T. brucei isolated from infected flies were tested for their response to the lethal effects of human blood (Blood Incubation Infectivity Test, BIIT) and also characterized using isoenzyme electrophoresis. Six of the 26 T. brucei tested were BIIT positive, two of which had enzyme profiles identical to human isolates. The 26 isolates were grouped into 10 zymodemes. Two zymodemes were identical to T. b. rhodesiense isolated from sleeping sickness patients, one of which was identical to the predominant zymodemes among patients from Lambwe Valley area. The other zymodeme was identical to an isolate from a patient from the Busoga (Uganda) sleeping sickness epidemic focus. These two Zymodemes were BIIT positive. It is suggested that there has been an exchange of human infecting organisms between the Kenya and the Uganda foci.