532 SCIENCE IN AFRICA 



sleeping sickness control, partly by improving the existing treat- 

 ment service and partly by a protective campaign of communal 

 clearing, movement, and concentration of population. The cost 

 of this second part of the scheme is to be defrayed by a five years' 

 free grant from the Colonial Development Fund, whilst the cost 

 of improved treatment is to be defrayed by the Nigerian govern- 

 ment (Nigeria 1936, D.R.). There is a trypanosomiasis bureau 

 in Southern Rhodesia which not Only correlates the work of all 

 government departments on this subject, but has a special 

 laboratory, in charge of Mr. Bevan, a Beit Fellow. As in East 

 Africa the disease is by no means so common now as in past years. 

 In 1935 a survey, involving careful examination of natives, was 

 made in the Sebungwe area to the west of Goheve. Although the 

 disease was formerly known to be present, no cases of sleeping 

 sickness were found. 



With regard to control, the East African sub-committee of the 

 Economic Advisory Council (1935) described three types of 

 possible measures: (i) administrative methods, such as the evacu- 

 ation of population from an infected area, the control of move- 

 ments of population (in search of work, etc.), the clearing of water 

 places, and the concentration of settlement; (2) the control of 

 tsetse flies; and (3) control by chemotherapy, that is to say, 

 treatment by means of various drugs. 



The first of these methods is followed in Uganda, the Congo, and 

 Nigeria. As mentioned above, the usual infection of T. gambiense 

 is conveyed by G. palpalis, and in the drier areas of Northern 

 Nigeria by G. tachinoides, both of which species must have damp 

 and shade for breeding. Hence the most effective way of control, 

 which has been widely employed in Uganda and the Congo, is 

 to remove natives from infected banks of rivers or lakes, and to 

 allow them to m.ake watering and washing places only in specially 

 cleared strips. Wide stretches of shore along the great lakes and 

 rivers are thus closed to native occupation. The fly does not die 

 out in the absence of human beings, since it can obtain abundant 

 food from wild mammals and reptiles, but in the absence of the 

 human reservoir the sleeping sickness infection is lost after some 

 time. Thus in Uganda population has recently been returned, 

 under close control, to many of its former holdings along the lake 



