340 Agricultural Gazette of N.S.W. [Maij 3, 1920. 



mouth disease and many other higlily infectious diseases. Instances of 

 successful control may be observed in the suppression of inlanders amongst 

 the horses of the British armies, the reduction in the mortality from anthrax in 

 New South Wales, and the control of rinderpest in India and Africa. Nor 

 is eradication of many diseases impossible, as England showed in dealing 

 with contagious pleuro-pneumonia in cattle, and Australia with scab in 

 sheep. Still, no matter how efficient the State service may be, it is not 

 always possible to prevent disease being spread from farm to farm, and herein 

 the co-operation of the farmers themselves is most necessary. To this end it 

 is very desirable that a knowledge of what constitutes infectious disease, and 

 what diseases they are likely to meet with, should be widespread am'Mig 

 stock-owners, and that they should realise how much the prevention <jf the 

 spread of these complaints lies in their own hands. 



Infectious diseases are due to micro-organisms of various kinds, and when 

 these gain entrance into the body and multiply in the organs, tissues, in' 

 cavities, and produce disease, an infection is said to occur, and the disease so 

 produced is called an infectious one. Many such diseases occur in Australia 

 though fortunately the country has remained free from a number of the 

 most serious, the reasons being the long voyage from most of the stock 

 exporting countries in the old days, and the strict quarantine regulations in 

 later days. Yet in one way or another various infectious diseases have been 

 introduced, and the list is now a fairly extensive one. In all animals anthrax 

 and tetanus may occur ; in horses, strangles and induenza ; in cattle, 

 tuberculosis, actinomycosis, pleuro-pneumonia contagiosa, blackleg, contagious 

 abortion, contagious mammitis, tick fever, and hsemorrhagic septicaemia ; in 

 sheep, caseous lymphadenitis '^ in ings, tuberculosis, swine fever, and swine 

 plague ; and in fowls coccidiosis and spirochietosis. It is not suggested 

 that this list includes all that may be present or may be found, but those 

 mentioned are the most important. 



Methods by which Infection may Occur. 



It will be obvious that measures which may prevent the spread of some of 

 the above will be useless against others, but at the same time certain general 

 principles can be laid down which will be of value in almost all cases, 

 i^efoi-e considering such measures it is necessary to enumerate the methods 

 by which infection of a farmer's stock may occur. These may be sec dowii 

 a.s follows : — 



1. By the introduction of diseased stock on to a farm. 



2. By tke introduction of infectious material on the clothing, boots, «te.,. 



of &todk attendants or other persons coming from infected farms. 



3. By the introduction of contaminated matter by uncontrolljed agencies. 



such as birds, dogs, &c. 



4. I?y the contraction of disease by healthy animals whilst temporarily 



away from the farm. 

 0. By taking healthy stock on to an infected farm. 



