540 SCIENCE IN AFRICA 



ally in the case of rural areas, where circumstances must determine 

 whether the attack should be primarily against all rodents, domes- 

 tic or wild, or whether it should involve prophylactic vaccination 

 of humans. 



RELAPSING FEVER 



This disease may be transmitted by ticks or lice, and is charac- 

 terized by high fever at regular intervals of about a week. The vec- 

 tors have been mentioned previously in Chapter X, where references 

 are given to literature. The East African relapsing fever, known 

 also as tick fever, is transmitted by a tick, Ornithodorus sp., which 

 frequents native huts and camping sites. It is endemic in certain 

 areas, especially along trade routes, and has sometimes reached 

 epidemic proportions. For example, in Uganda, in prisons in 

 Ankole District, infestation has occurred to such an extent that 

 for a while every non-immune prisoner inevitably acquired the 

 disease. Methods of control depend on eradicating the tick [see 

 page 297). 



The best known variety of relapsing fever is that of which the 

 vector is the body louse. This disease (League of Nations 1930b) 

 was endemic in French Guinea in 1921, and during the following 

 years spread across equatorial Africa to the Sudan, having a very 

 high case mortality rate among Africans of about 18 per cent, 

 compared with i per cent to 5 per cent in Europe. Cases are not 

 now reported, so that the serious views that were taken at one 

 time are to-day not justified. 



TYPHUS FEVER 



Related to relapsing fever but probably distinct, are the several 

 diseases in the typhus group which cause considerable morbidity 

 and mortality among the Bantu population of South Africa. 

 Much research on these has come from Dr. A. Pijper's private 

 laboratory and a detailed account of the position has been given 

 by Dr. E. H. Cluver (1934). Clinical and pathological investiga- 

 tion over a number of years has shown that there are three distinct 

 typhus-like diseases in South Africa, which are transmitted by 

 ticks, rat-fleas, and lice. Tick-bite fever occurs chiefly in the low- 

 lying region of the Transvaal, but cases are known as far north and 



