470 HORSE, SWINE AND POULTRY DISEASES 



Contract. A contract is required of all using the serum, releas- 

 ing the laboratory from all responsibility in the matter. 



Cost of Serum,. A charge of two cents per cubic centimeter is 

 made for the serum. This is below the actual cost of production and 

 testing. (Mich. Cir. 6.) 



Experiment has proved that copper salts have no value as a pre- 

 ventive of hog cholera. (Neb. 19th A. R.) 



Plan for Eradicating Hog Cholera by Serum Immunization. 

 If the greatest good is to be accomplished we should not be content 

 simply to reduce the losses from hog cholera, but should undertake 

 systematic efforts to eradicate the disease. The course which hog 

 cholera usually takes when it appears in a neighborhood is well 

 known. A herd develops the disease, which may not be recognized as 

 hog cholera for several weeks after it has made its appearance. Fol- 

 lowing this the neighbors' hogs become infected and the disease 

 spreads rapidly, the number of new foci increasing more rapidly as 

 the infected area widens, until finally the losses in a single county 

 may be enormous. 



It is evident that in order to control the disease there must be 

 some means of confining it to the original center of infection. This 

 has been attempted by the British Government through the quaran- 

 tine of farms where hog cholera exists and the slaughter of all in- 

 fected animals. That such procedures alone do not yield the desired 

 results is shown by the official reports of the continued prevalence 

 of hog cholera in England. In the United States such methods w r ould 

 not be suitable, for, aside from the enormous expense involved, it 

 would, in my opinion, be entirely impracticable to thoroughly dis- 

 infect extensive farm premises and to carry out a quarantine which 

 would be effective against such carriers of disease as dogs, crows, buz- 

 zards, and other animals. 



It has already been stated that the serum from hyperimmunized 

 hogs can be used to protect hogs from hog cholera and that a large 

 saving can be effected if the serum is applied promptly after the dis- 

 ease appears in a herd. Why, then, should not this serum be used 

 as an agent for the eradication of hog cholera? It seems reasonable 

 to believe that it can be used successfully for this purpose, but com- 

 plete success can not be expected without proper organization and 

 the direction of the work by health authorities. In order that the 

 possibilities of well-directed work along these lines may be brought 

 to the attention of those who may in the future have this work to 

 perform, the following plan for combating hog cholera through 

 serum immunization is submitted : 



1. The serum should be prepared by the State Experiment Sta- 

 tions or by State live-stock sanitary boards which are properly 

 equipped with laboratory facilities, the efficacy of all serum to be 

 determined by such laboratories before distribution. 



2. The field application of the serum should be in the hands of 

 the State live-stock sanitary board or State veterinarian. 



3. The State should be organized into districts, each in charge 

 of a deputy State veterinarian or a deputy appointed by the live-stock 



