57 



chambers for the development oi any trypanosome ingested. They 

 can afterwards be dissected and their body contents examined and 

 the existence or not of the disease in a given patient be determined 

 accordingly. 



Spreull (J.). East Coast Fever Inoculation in the Transkeian Terri- 

 tories, South Africa. — Jl. Gomp. Path. & Therap., London, xxvii, 

 pt. 4, December 1914, pp. 299-304. 



After a brief summary of the spread of East Coast fever in South 

 Africa, especially as to its invasion of the Transkeian Territories and 

 the measures undertaken against it there [see this Review, Ser. B, ii, 

 p. 163], the following precautions, w^hich are regarded as essential 

 towards the production of a high percentage of successful immuni- 

 sations, are given : — The cattle must be free from infection at the date 

 of inoculation ; they should be inoculated on clean veldt {i.e., un- 

 infected pasturage) ; they should be kept on clean veldt for 14 days 

 after inoculation. Vaccine animals should be carefully selected, and 

 only those which are well advanced in the disease should be killed for 

 this purpose ; such vaccines, though they transmit East Coast fever 

 upon inoculation and frequently cause hea\^ loss, are more satis- 

 factory than those taken from an animal in the earher stages of the 

 disease. The latter often fail to transmit infection, and later, when 

 the herd is subjected to the tick test, a very heavy mortahty ensues. 

 When virulent vaccines are used, the cattle which survive transmitted 

 East Coast fever are almost certain to resist the tick test satisfactorily. 

 The vaccine should be injected within six hours of manufacture in 

 winter, and within four hours in summer. It is advisable to mix 

 together the vaccines of several animals so as to produce a medium 

 with uniformly high powers of immunisation. After the fourteenth 

 day the inoculated animals should be placed upon highly infected and 

 tick-infested veldt ; they must not be dipped after this date 

 and the pathogenic tick should be given every chance to attach itself. 



Some notes on the percentages of immunisation, virulence of vac- 

 cines, inoculation accidents, and the best season for inoculation are 

 given. Along the coast, where little dipping had been practised, 

 where the grass is rank and ticks plentiful, a six weeks' tick test was 

 found to be ample in summer. In higher areas, w^here the grass is 

 short and ticks not so plentiful, the period was lengthened to eight 

 weeks. During winter, even three months was not equally effective. 

 The question of second inoculations is discussed and it is thought that 

 a second vaccination is necessary where previously inoculated cattle 

 fail to become properly tick tested. 



Cattle which have undergone the inoculation successfully, and have 

 passed through a satisfactorily severe tick test shortly thereafter, have 

 maintained a very high degree of immunity under the present con- 

 ditions in the Transkei ; that is to say, they have maintained their 

 immunity for three years and over. Whether such cattle would do 

 so if they were removed from the bites of pathogenic ticks for a period 

 of two years or more, and then re-exposed to them is still doubtful. 

 In conclusion, it is pointed out that since East Coast fever gained a 

 footing in the Transkeian Territories it has caused the death of about 

 900,000 cattle, and its eradication, even under the most favourable 

 circumstances, will not be effected for some years. 



