214 PRINCIPLES OF VETERINARY SCIENCE 



(4) The Removal of Infected Animals. — The first step in 

 preventing the spread of an infectious disease is to remove all 

 affected animals to a place where they may be kept segregated. 

 This is to prevent communicating the infection to others. In 

 order to discover animals that are affected, the knowledge pos- 

 sessed by an experienced veterinarian is needed. Even he 

 does not rely upon a physical examination, but will bring to his 

 aid special instruments and biologic diagnostic agents. The 

 most commonly employed biologies of this kind are tuberculin 

 for the diagnosis of tuberculosis, johnin for Johne's disease, and 

 mallein which shows whether an animal has glanders. When 

 properly used, these preparations are capable of determining 

 cases of disease in the very earliest stages and before external 

 symptoms are evident. None of them is harmful if used accord- 

 ing to approved methods. 



(5) The Establishment of a Quarantine. — By quarantine is 

 meant the limitation of freedom of movement of animals that 

 have been exposed to a communicable disease for a period of time 

 equal to the incubation period of the disease to which they have 

 been exposed. Measures that are designed to safeguard against 

 the spread of disease and are useful in preventing diseases from 

 getting a foothold are the basis for the establishment of a quaran- 

 tine. To be effective, a quarantine should include both the 

 infected and the exposed animals. The infected animals should 

 be surrounded by barriers to take care of the excreta and con- 

 taminated litter, and should have a trained attendant who 

 understands and will observe the necessary precautions against 

 the distribution of disease and see that others also observe them. 

 If this is not convenient, the attendant should be provided with 

 a change of clothing, more especially shoes and overalls. The 

 exposed animals should be prevented from contact with flies, 

 provided with good water and feed, and confined to a clean, well 

 ventilated stable. 



During the quarantine period disinfectants should be used 

 freely. In case an animal dies, especial precautions are to be 

 exercised to sweep, wash, and disinfect the place where it was 

 kept and to burn the litter. 



An official quarantine is issued by order of federal or state 

 five stock sanitary officials, but cannot be effective unless public 

 sentiment is back of the order. Strong cooperation among 



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