DISEASES OF SWINE 611 



separated until the nature of the disease is determined. Such 

 a lot set apart for this purpose may prevent outbreaks of very- 

 serious diseases. 



HOG CHOLERA 



Hog cholera is an infectious disease of swine. It exists in all 

 sections of the United States, but is particularly prevalent 

 in the corn-belt. In that section it is the most dreaded 

 disease to which swine are subject. Not so many animals 

 are condemned at the large packing houses because of this 

 disease, as of tuberculosis, but this is due to the nature of the dis- 

 ease. With cholera the hogs die or recover quickly, while with 

 tuberculosis they may linger for months. Cholera varies in its 

 virulence; sometimes comparatively few hogs that have it will 

 die, while at other times nearly every animal in the entire herd 

 will succumb to the disease. When the disease once appears, it 

 spreads very rapidly, not only among the animals of a herd, but 

 across the country from one farm to another. 



Manner of spreading the disease. — Cholera is a germ disease 

 and may be spread in many ways. These germs are very hardy 

 and vigorous. They are able to live for a long time in the 

 water of ponds and streams; they may live in the soil for at 

 least three months and in accumulations of straw and litter for a 

 much longer time. The hog, taking in these germs either by in- 

 haling with the breath or by ingestion with the food, is likely 

 to contract the disease. Only the very smallest particle is 

 necessary to convey the germ. Thus, an attendant passing 

 from a lot of infected hogs to a lot of healthy ones may carry 

 the infection on his shoes; dogs, chickens, pigeons, and even 

 birds are known to have carried the germs. The wind 

 blowing particles of dust from place to place will also carry with 

 it sufficient of these germs to produce the disease. A cholera 

 hog having access to a stream may contaminate the water 

 sufficiently to infect animals miles below. 



