Sirine Plague. 497 



severely ill and undergo spontaneous recovery. A few others, it may 

 have been observed, contracted only a transient illness. 



Immunity Conferred uv Attack. 



As a matter of fact, all susceptible animals may be attacked, and 

 it is the experience in other parts of the world that when animals have 

 once been attacked they are rendered immune to subsequent attacks. 

 Again those that survived a severe attack were possessed of less 

 susceptibility, or greater resisting power, than those that succumbed. 



Stkps to Pursue to Prevent Si'Read of Disease. 



When the disease appears on a place, all pigs should be kept 

 in secure enclosures, and should not be allowed to wander far and 

 wide over the farm. On no account should they be permitted to 

 trespass on roadways. They should, above all things, be prevented 

 from fouling water courses. By sti'ictly observing measures of this 

 nature, the virus is prevented from being carried to other farms and 

 infecting other lierds. 



Swine plague is one of the filth diseases, and insanitary conditions 

 perpetuate it, so the most scrupulous cleanliness must be exercised to 

 stamp it out. Tlie styes and other enclosures must be thoroughly dis- 

 infected with approved disinfectants, and the operation must be 

 repeatedly carried out. 



In order to prevent infection reaching a farm, one must be careful 

 to see that he does not obtain possession of a diseased animal. One 

 must be sure of the source of any fresh pigs that are introduced. 



Swine, which are affected with the plague in an occult form, may, 

 innocently enough, be moved about from point to point spreading the 

 disease along their course without exciting the suspicion of the 

 inspectors and others as to the gravity of the hidden disorder. The 

 disease may lurk in a chronic form in some animal in which it is 

 thought the disease had become extinct, and an animal of this kind 

 may be the focus of an outbreak. Where movement of pigs is 

 permitted, branding must be effective and the records of brands care- 

 fully kept, so that the origin of all pigs may be traced. 



When the disease makes its appearance at a pl;i,ce in a district 

 previously free from it, it comes to be a question as to whether it is not 

 prudent under such circumstances to stamp out the whole herd on the 

 infected place forthwith. If only a few animals remain, it would be wise 

 to kill them off", as they may suffer from the disease in a hidden form and 

 thus continue to infect the premises. However, the slaughter of affected 

 animals, and the c|uarai]tining and isolation of the ap])arently healthy 

 in sanitary quarters, is a discreet course to follow, and perhaps should 

 l)e given a trial before more drastic measures are resorted to. Under 

 judicious restrictions, diseased animals even might be subjected to 

 treatment, with the view of inffuencing the course of the disorder. 

 The only treatment that can be expected to avail is one based on Sero- 

 Therapy or Vaccination. 



