450 SCIENCE IN AFRICA 



mortality during transit was estimated to be almost 50 per cent, 

 and serious situations resulted from the spread of disease along 

 the routes, but in recent years this high death rate has been reduced 

 almost to nil by a system of health tickets and by inoculating every 

 animal before the beginning of the journey, by limiting the use of 

 cattle tracks to a few which are known to be kept clear of tsetse, 

 and by a series of inspection centres along each track where any 

 animals added to the herds in transit are likewise vaccinated. 

 (Nigeria, Veterinary, 1935 onwards, D.R.) 



Rinderpest is the disease which has absorbed most of the energies 

 of the veterinary departments. The policy, as in East Africa, is to 

 immunize young animals wholesale while they are still healthy. 

 At the veterinary laboratory at Vom, in Northern Nigeria, very 

 large quantities of serum and vaccine are prepared. In 1936 the 

 figures were sero-virus — 382,732, spleen-vaccine — 274,157 and 

 serum alone — 5,221. (Nigeria, Veterinary, 1936, Z).i?.) Theserum 

 double inoculation method, which gives an immunity amounting 

 to lifetime when injected into adult animals, is favoured in Nigeria. 

 The serum cannot be made, however, for less than one shilling 

 per dose, and its use is always followed by a mortality from other 

 diseases, mainly trypanosomiasis, as a result of weakness when the 

 rinderpest symptoms make their appearance. This mortality was 

 formerly as high as 20 per cent, but has now been reduced to 

 about 3 per cent. The cattle owners willingly suffer an initial mor- 

 tality for the sake of the eventual immunity of their herds. Both 

 the Fulani and Hausa bring their herds without any persuasion to 

 the immunization camps, of which there were some fifty-seven 

 operating in 1 936, and where the cattle are kept in quarantine for 

 a month. The laboratory at Vom has been unable to obtain locally 

 the requisite number of bulls for the preparation of serum and 

 virus, and hence secondary centres under the Native Administra- 

 tion have had to be started at Kano, Sokoto, and elsewhere in 

 the Northern Emirates (plate vii). 



The spleen vaccine, which can be made far cheaper than the 

 serum, has proved to give immunity for only nine months or so, 

 and hence is not favoured by the cattle owners. It has proved very 

 valuable, however, in immunizing cattle on their way to the sou- 

 thern markets, and every animal entering Nigeria from the adjoin- 



