194 VETERINARY HYGIENE 



thither with the utmost ease; being of material substance, they 

 find resting places on all sorts of media that are in turn passed 

 from place to place and animal to animal. 



Lack of accommodation often prevents the separation of the 

 sick from the healthy, and the insanitary condition of so many 

 animal houses in which we have to treat our patients militates 

 against our attempts both to treat the disease and to prevent its 

 spread. We do, however, possess one advantage over our medical 

 confreres. We can destroy infective animals and obliterate all 

 traces of infection should it be desirable to do so. 



Infection is transmitted from the diseased to the healthy in a 

 great variety of ways. Direct contact with an infective animal is 

 the most patent but by no means the most common method of 

 spreading disease. If it were the chief cause of disease spreading 

 from one animal to another then prevention would be a compara- 

 tively easy matter. 



Unfortunately, infection is chiefly disseminated by indirect 

 means, and so its control is much more difficult. Any material 

 that has been in contact with an infective animal may carry the 

 contagium. An infective material such as has been in contact with 

 an infective animal may pass the contagium on to other material, 

 which in turn may transmit it to a receptive animal. Disease is 

 carried from diseased to healthy by other animals acting as passive 

 carriers. People may act as passive carriers by conveying the 

 infective material on their hands, clothes, and boots. Vermin, 

 birds, flies and other insects carry infection. Food and water are 

 not uncommonly the culpable agents in spreading disease, and the 

 air and wind are notable transmitters of infection. 



The fact that the contagium of disease may enter the body by 

 inhalation, ingestion, inoculation, as well as possibly absorption, 

 materially increases the difficulties with which one has to cope. 



Chief among the measures taken to prevent the spread of 

 infectious diseases are isolation of the infected animal and infective 

 material; notification of the existence or suspected existence of an 

 infectious disease to a veterinary practitioner and, in the case of a 

 scheduled disease, to the authority whose duty it is to put in motion 

 active measures for the prevention of its spread; disinfection of 

 all media likely to hold or to carry infective material and general 

 prophylactic measures which should be taken to prevent the appear- 

 ance of an infectious malady in clean premises or districts. 



ISOLATION. With the controlled diseases certain specific 

 instructions are issued to the owner of the animal as to what he 

 must do and what he must not do. 



