HOG CHOLERA; PREVENTION AND TREATMENT: 



17 



hyperimmunized its blood contains a large amount of protective sub- 

 stances or antibodies,' and it is from such blood that anti-hog-cholera 

 serum is prepared. 



The fact that a serum made in this way will protect hogs from 

 contracting cholera was first brought to the attention of the authori- 

 ties in the various States by the Bureau of Animal Industry in 

 1908-0. Following this several State institutions began the prep- 

 aration and distribution of the serum, and subsequently its manufac- 

 ture was taken up by private concerns all over the United States. 

 The efficacy of the serum is now recognized generally both in the 

 United States and in foreign countries. 



While the serum is regarded as most efficacious when administered 

 as a preventive, it undoubtedly has considerable curative value pro- 

 vided it is administered when hogs are in the very early stages of 

 the disease. 



Beginning in 1913, the Bureau of Animal Industry conducted ex- 

 periments in IT counties in 15 different States to determine the possi- 

 bility of reducing losses from hog cholera by a systematic campaign 

 embracing limited quarantine and sanitary measures and the use of 

 the preventive-serum treatment. In the course of these experiments 

 231,136 hogs were treated in infected herds, with a loss of 13.1 per 

 cent, notwithstanding the fact tbat 85,547, or 30.5 per cent, of the 

 number were sick, showing high temperatures or other evidences of 

 disease at the time of treatment. 



During the same period 19,208 hogs were treated in uninfected 

 herds for protection, with a total loss of only 49 hogs, or one-fifth of 1 

 per cent. The few deaths recorded probably were due to causes other 

 than cholera, and the losses from that source may be regarded as nil. 



The results of these experiments are shown in the following tables: 



Table 2. — Results of serum treatment in infected herds, 1913, 1914, and 1915. 



Condition of hogs and method of treatment. 



Hogs 

 treated. 



Hogs died. 



Hogs sick when treated : 



Number. 

 2, 448 

 83, 099 



Number. 

 713 

 23, 990 



Per cent. 

 29.1 

 28.8 



Serum alone 1 



Hogs apparently well when treated: 



85, 547 



24, 703 



28. 8 



81, 289 

 67, 300 



3, 070 

 3, 063 



3.7 

 4.5 



Serum alone 



Total 



148,589 



6, 133 



4. 1 



234, 136 



30, 836 



13.1 





1 The two systems of inoculation used in protecting hogs from cholera are explained 

 under later headings. 



