CHAPTER XII 



INFECTIOUS DISEASES 



Hog eholera Anthrax 



Swine plague Tuberculosis 



Infectious necrotic enteritis Swine erysipselas 



Necrobacillosis Rabies 



Paratyphoid infection Foot-and-mouth disease 



Salmonellosis Tetanus 



Malignant edema 



Hog Cholera 



Hog cholera is a specific septicemic disease of swine characterized 

 by parenchymatous degeneration and more or less hyperemia and 

 hemorrhages of various tissues of the body. It is infectious and 

 contagious. 



Geographical distribution. — The first indentified outbreak of hog 

 cholera in the United States occurred in Ohio in 1833. From this 

 original center it has spread widely and now prevails more or loss 

 continuously in very state of the Union as well as in the surrounding 

 countries, including the island possessions of the United States. The 

 disease was positively recognized in England in 1826, and it still 

 prevails there. In 1896 approximately one-third of the swine popu- 

 lation of England died of cholera. The disease was introduced into 

 Denmark in 1887, and spread into Sweden the same year. It also 

 appeared in France in 1887. Hog cholera, or a very similar disease, 

 appeared in Germany in 1866, Prussia, Austria, and Hungary were 

 invaded in 1895. From all reports, it is apparent that hog cholera 

 prevails in practically every country in which swine are maintained. 



Hog cholera was first investigated systematically in America in 

 1885, under the directions of Salmon. The disease was thought, and 

 apparently proved at that time, to be due to a short, rod-shaped 

 bacteria. 



De Schweinitz and Dorset further investigated the disease in 1903, 

 and the Bureau of Animal Industry have continued their investiga- 

 tions up to the present time. 



Extent. — Information obtained from various sources indicates that 

 hog cholera has been prevalent in America for the past fifty years. 



