Diseases, Ticks, and their Eradication. 157 



Stock broug'lit on to the tifk-free piece of grouiul will naturally 

 bring' with them the ticks again, which will increase in the usnal 

 manner and after clue time be present in g'reat numbers. If it is oud' 

 intention to completely get rid of the ticks precautions must be taken 

 not to bring' ticks with the cattle into the clean veld. This can be 

 done by dii)ping- or spraying- the animals and immediately removing- 

 them on to the clean farm, but it can also lie done without dipping and 

 spraying'. For this purpose the cattle should be placed on a smaller 

 piece of tick-free ground, sufficiently large to carry them for about 

 four tosix weeks, and should be kept there for this period. AVe will 

 call this the quarantine paddock. During this time all blue ticks 

 will have dropped off, and if it rs only intended to eliminate these the 

 removal of the clean beasts into the final clean area can be done. 

 AVithin four weeks engorged larvae and nyniphae of the brown and 

 red ticks which dropped off during the first days of the removal 

 into the quarantine paddock develop to a succeeding stage (nymphae 

 or adult), in which they seek a new host, and these might be carried 

 by the stock into the clean veld if this removal is done later than four 

 weeks after the introduction of the cattle into the quarantine paddock. 

 It is therefore advisable to transfer the cattle after about eighteeji 

 days to an adjoining clean piece, where they must be kept for a 

 further period of eigditeen days; there the remainder of the blue ticks 

 will drop off and no new ticks can get on. After this period the .stock 

 can safely be moved to a clean area. The quarantine camps are then 

 closed for all stock for at least fifteen months. It is also possible thai, 

 liy the same procedure the bout tick would be got rid of, so thai, 

 theoretically speaking, it is within the range of possibility — wiihout 

 the use of dips and sprays — to get rid oi all ticks. In practice this 

 would have to be carried out by splitting the farms up into fenced 

 paddocks, which for a period of about fifteen montlis would have to 

 be kept free of animals. Dipping, however, is a much safer method 

 of clearing a farm of ticks, and should be adopted in preference to 

 other measures. 



Ekadication and Prevention of Diseases. 



Eiuulinitioii (if diseases in witicli tJte aninials do not act as a 

 i-esen-<iii\ ciz.. East Coast fever and heartwater. — It may be taken as 

 an axiom that destroying ticks means eradicating disease. How this 

 can be done has just been demonstrated. It may safely be said that, 

 as far as the most formidable tick-borne disease — East Coast fever — 

 is concerned, we have no better remedy for saving cattle and eradi- 

 cating the disease than dipping. It has been pointed out before tluit 

 an infected tick does not discharge the infection before it has been 

 attached for at least sixty hours, but frequently later than this time 

 and up to 120 hours. Hence if East Coast fever lireaks out on a 

 farm and the cattle are immediately put into a dip, and this dipping 

 is repeated every third O'r fourth day, all cattle that have not been 

 infected on the date of dipping will be safe. The disease can thus be 

 suddenly arrested and only the animals already infected will die off. 

 If the dipping is now systematically carried out in as short an 

 interval as three to five days (in the latter case in a seven-day-stiength 

 dip and su))i)lemented by dressing) the disease will be eradicated after 

 the lapse of hfteen months. Since, however, all farnrs do not yet 



