2. ; , < HOG CHOLERA 



France, and there is evidence that prior to 1833 

 outbreaks of a similar nature occurred in other 

 parts of continental Europe. But even with pres- 

 ent-day knowledge hog cholera and other infec- 

 tious swine diseases are sometimes difficult to 

 differentiate, and we are thus in the dark relative 

 to the true causes of all the earlier outbreaks. 



According to the most authentic records, hog 

 cholera appeared in England in 1862, and from 

 there, in 1887, it was carried to Sweden in a ship- 

 ment of boars. In this same year the disease ap- 

 peared in France and Denmark, and its spread 

 was so rapid and persistent that all European 

 countries have suffered severely from its ravages. 

 To-day, no large area devoted extensively to swine 

 raising is entirely free from hog cholera, and so 

 far as we have been able to ascertain, no country, 

 once invaded, has succeeded in freeing itself of 

 the malady. The Scandinavian countries seem to 

 have suffered least from its effects. 



Because of its rapid spread and high mor- 

 tality hog cholera has caused and is causing enor- 

 mous losses, the estimate being that in the United 

 States it is responsible for ninety per cent of the 

 deaths from all swine diseases. In this country 

 the annual losses caused by it during the last four 

 decades have ranged between $13,000,000 and 

 $200,000,000, and in the two decades ending with 

 the year 1914 the average annual loss per one 



