^38 SCIENCE IN AFRICA 



anti-rat campaigns, the use of cyano-gas in huts and other sanitary 

 measures, as to a natural decHne in the epidemic wave. Probably 

 associated with the plague area in Uganda is a small centre in the 

 Belgian Congo around the south end of Lake Albert. This has been 

 under investigation for some years, and does not seem to be either 

 spreading or decreasing (Congo Beige 1928, A.R., p. 77). Various 

 endemic centres occur elsewhere in East Africa, notably in Tan- 

 ganyika, for which an account of plague has been published 

 (Tanganyika 1931). 



Various parts of West Africa have had occasional outbreaks of 

 plague, but the disease has not yet attained a strong foothold 

 except, perhaps, in Angola and Senegal. In Angola the first 

 outbreak was in 1921 at Loanda, to which the disease was prob- 

 ably introduced from Lisbon. The epidemic rapidly reached a 

 climax and has steadily decreased, perhaps as a result of inten- 

 sive campaigns in burning native huts to destroy rats. Up to 

 now there has been no plague on the coast. Since 1932, the 

 South African plague carried by wild rodents has reached Angola, 

 but so far there have been comparatively few cases. It is hoped 

 that the desert conditions in Southern Angola are so unfavourable 

 to rodents that the disease will be kept out of most of the territory 

 (Ribeiro 1936). 



Several ports on the Guinea coast have been centres of minor 

 outbreaks, which have occurred in French Guinea, the Ivory 

 Coast, the Gold Coast, and Southern Nigeria; the last being in 

 Nigeria, where, however, there has been no case since 1933. The 

 infection of Senegal from Dakar and Rufisque has been far more 

 severe, but fortunately has kept to a belt of country some 100 

 km. long by 25 km. wide. The climax was reached in 1924, when 

 some 1 ,400 people died from plague, but since then the epidemics 

 have been reduced to quite small proportions. 



Every port is a potential source of danger, and in this connection 

 special research on rats and their parasites, carried out at the Sir 

 Alfred Jones Laboratory at Freetown, is important. Mr. Davis of 

 the Wellcome Research Institute has been financed by the Royal 

 Society of Medicine to make a census of rats and their fleas in 

 Freetown and the neighbourhood, where the rat-flea index was 

 previously known to be higher than in either Lagos or Accra, 



