ANIMAL INDUSTRY 45 I 



ing French territories is immunized with spleen vaccine at quaran- 

 tine stations. Similarly in the Gold Coast, rinderpest is now kept 

 completely under control by a system whereby all stock entering 

 the country from the French Sudan is immunized at the frontier. 

 The serum and vaccine is made at Pong-Tamale. 



For black quarter some 4.'^o, 12^, and for contagious pleuro-pneumonia 

 some 117,543 vaccinations were made in Nigeria in 1936, usually 

 at the same time as rinderpest. It is still something of a mystery 

 why east coast fever has never reached West Africa in view of the 

 cattle movements back and forth through the Sudanese regions. 

 Presumably some ecological factor serves as a natural control, and 

 it is often suggested, for instance, that ticks cannot withstand the 

 long dry season of West Africa, but, as mentioned in Chapter X, 

 among other ticks collected at Pong-Tamale in the Gold Coast 

 were specimens of the vector of east coast fever. Regular dipping, 

 which is so important in East and South Africa, is of much less 

 consequence in the West, although certain tick-borne diseases 

 such as redwater make their appearance in epizootic form at 

 intervals. Mr. Stewart at Pong-Tamale, in investigating the blood 

 parasites of cattle, has brought to light several forms of Theileria 

 closely related to T. parva of east coast fever. One of these is the 

 cause of a turning sickness similar to that of East Africa (Gold 

 Coast, Veterinary, 1935-6, D.R.). 



Trypanoso?niasis is undoubtedly the most important cattle disease 

 in West Africa. In Nigeria, for example, it has been estimated 

 that in the Northern Territories 33 to 40 per cent of cattle carry 

 the disease, although it usually only breaks out when the animals' 

 vitality is reduced by rinderpest, inoculation or poor feed. In 

 the Southern Territories right along the Guinea Gulf there is 

 little doubt that every head of the dwarf immune cattle mentioned 

 above carry the trypanosomes. It is certain that many distinct 

 strains of trypanosomes exist, and that immunity to one does not 

 involve immunity to another. Thus, herds which are immune in 

 areas where G. tachinoidesis the prevalent tsetse fly have been known 

 to suffer up to 100 per cent deaths when moved into G. morsitans 

 areas. Again the herd of shorthorn cattle introduced from the 

 Gold Coast to Ilorin, although completely immune in their own 

 home, suffered severely in Nigeria, but in this case factors of other 



