6 



FARMERS* BULLETIN 834. 



Fig. 1. — Estimated number of hogs on hand Jan. 1, 1014, and losses from bog 

 cholera for year ending March 31, 1914. 



At times the value of hogs destroyed by cholera in the United 

 States has amounted to about $05,000,000 in a single year, and the 

 average annual loss for the last 40 years probably has not been less 

 than $30,000,000. This represents merely the direct losses; if the in- 

 direct losses could be computed these figures would be increased 

 greatly. Figure 1 shows for each State the estimated number of hogs 

 on hand January 1, 1914, and the estimated losses from cholera 

 during the year ending March 31, 1914. Table 1 gives similar infor- 

 mation for the years 1913 to 1917, inclusive. 



The losses from hog cholera in the United States during the last 

 24 years are shown in figure 2. It will be noted that the decline 

 since 1914 has been quite rapid. 



THE CAUSE OF HOG CHOLERA. 



Hog cholera is a highly contagious disease of swine, caused by a 

 germ or microorganism which is present in the blood, urine, feces, 

 and the eye and nose secretions. It is accompanied by fever, has a 

 high death rate, and, so far as known, does not affect other animals 

 or man. 



The germ has never been cultivated artificially in laboratories, as 

 many other infectious germs have. It can not be seen, even with the 

 most powerful microscopes; it passes readily through the pores of 

 the finest filters, which will hold back all visible bacteria ; and it is 

 known only by the effects which it produces. In these respects it 

 resembles the germs that cause foot-and-mouth disease in cattle and 

 yellow fever in man. Although insanitary surroundings and im- 



