CHAPTER XXVI 

 HOG-CHOLERA 



Hog-cholera is a liiglilv infectious disease of swine. It is 

 characterized by an inflammation of the lymphatic glands, kid- 

 neys, intestines, lungs and skin. The inflannnation is hemor- 

 rhagic in character, the inflamed organs usually showing deep 

 red spots or blotches. 



Ilog-cholera is especially prevalent in the corn-raising States 

 which possess a denser hog population than any other section 

 of the United States. In this country the loss from hog-cholera 

 in 1913 amounted to more than $no.000.000, and it may be 

 considered of greater economic importance than any of the other 

 animal diseases. 



Specific Cause. — The specific cause of hog-cholera is an 

 uUra-visihIe organism that is present in the excretions, secretions 

 and tissues of a cholera hog. De Schweinitz and Dorset in 1903 

 produced typical hog-cholera by inoculating hogs with cholera- 

 blood filtrates that were free from any organism that could be 

 demonstrated by microscopical examination or any cultural 

 method. The term ultra-visible virus is applied to the virus of 

 hog-cholera. 



The cholera hog passes off the virus with the body excretions. 

 Field data seems to show that the virus enters the body of the 

 susceptible hog with the feed and drinking water, and that the 

 disease is commonly spread by such indirect contact as shipping 

 hogs in cholera-infected cars, and visiting cholera yards. The 

 surest method of infection is by direct contact. 



Accessory Causes. — The usual method of introducing hog- 

 cholera into a neighborhood is through the importation of feed- 

 ing or breeding hogs that were infected with the disease before 



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