152 



Biological Therapy 



cholera virus. An active immunity which persists for the 

 life of the animal can be depended upon provided: 



1. That the animals weigh 40 lbs. or more at the time 

 of vaccination. 



2. That at least 2 c.c. of virus are used. 



3. That the virus is fully virulent and the serum fully 

 potent. Provided the animals are perfectly healthy at the 

 time of vaccination this treatment is followed by no visible 

 or thermic reaction. However, even though apparently 

 healthy, undesirable post-vaccination results may be ob- 

 served. These are due to the virus being superimposed upon 

 an already existing infection. 



In these immunizing procedures either whole blood or 

 clear anti-hog-cholera serum may be used with equally sat- 

 isfactory results. So-called ''clear virus" has not been found 

 dependable and is now an obsolete product. 



The care afforded vaccinated animals both previous and 

 subsequent to vaccination has considerable bearing on the 

 results obtained. The animals to be treated should be in 

 quarters which are dry and dean. If this precaution is not 

 observed abscesses or infection frequently result regardless 

 of the quality of the products used. Dust, mud or filth very 

 easily gain access to the body tissue through abrasions made 

 by the syringe needle and may be followed either by ab- 

 scesses or by septicemia. 



Whenever possible feed should be withheld for twenty- 

 four hours previous to treatment. Before and following 

 treatment enough water should be allowed to alleviate suf- 

 fering, but not enough to allow pens to become wet or dirty. 

 For forty-eight hours following vaccination the diet should 

 be very greatly restricted, while corn and concentrates are 

 best prohibited. The ration should consist of soft feed only 

 and the return to full diet should be very gradual. 



SYRINGES. Immediately upon completing the vacci- 

 nation, syringes should be washed inside and out with cold 

 water to remove any serum which may adhere to the same. 



The same syringe should never he used for vaccinating a second 

 herd without being re-sterilized. 



TEMPERATURES. Whenever possible the tempera- 

 tures of all animals to be vaccinated should be taken. When 

 the number of animals or lack of help precludes this a rea- 



