Il8 DISEASES OF SWINE 



the importation of diseased animals from England, 

 the same as in a number of other animal diseases. 

 The early history of the disease in this country 

 is not very definite. 



The first supposed outbreak of hog cholera oc- 

 curred in Ohio in 1838. During the next ten or 

 fifteen years scattering outbreaks occurred in the 

 states bordering on Ohio and in the South. Dur- 

 ing the next period in the history. of this disease, 

 from 1845 to i860, it became thoroughly planted 

 in all parts of the country, where hog raising was 

 followed to any great extent, through the move- 

 ment of animals from one part of the country to 

 another. 



Although its importance and contagious char- 

 acter were recognized at an early period, no effort 

 was made to prevent it from spreading. At that 

 time veterinarians and stockmen were not ac- 

 quainted with the nature of the contagion, and 

 the modern methods of dealing with such diseases, 

 and the opportunity to stamp out hog cholera at 

 a time when it might have been successfully con- 

 trolled, was lost. 



Causes. — ^The specific cause is the "bacillus of 

 hog cholera, discovered and described by the 

 Bureau of Animal Industry in 1885. It is a small 

 rod-shaped germ having rounded ends and from 

 .00005 to .00006 of an inch in length and .0000028 

 of an inch in breadth. It is usually present in 

 large numbers in the blood and diseased tissues 

 of an animal that has died of the disease. 



