SOME COMMUNICABLE DISEASES 363 



Treatment. — Medicines are unavailing once the disease is 

 well advanced. Therefore, efforts should be directed toward 

 preventing its spread to other animals. This is done by remov- 

 ing all unaffected animals to fresh quarters and by injecting 

 them with a bacterin composed of killed cultures of the hemor- 

 rhagic septicemia germs. Reports from the use of this bacterin 

 are contradictory and leave some doubt as to its efficiency. 

 Recently a specific antihemorrhagic septicemia serum, made by 

 hyperimmunizing animals against the germs, has been made 

 available. As yet not enough animals have been treated with 

 this product to justify a conclusion as to its merits. However, 

 this method of conferring immunity is logical, especially for 

 animals in infected herds. 



HOG CHOLERA 



Hog cholera is a preventable disease of swine that frequently 

 sweeps over the hog raising districts as an epizootic leaving mil- 

 lions of dead animals in its wake. Swine of all ages and breeds 

 are susceptible. The disease runs either an acute or chronic 

 course. The first cases in an outbreak are usually of short dura- 

 tion and succumb quickly; in subsequent cases the animals are 

 sick longer and may recover. 



Cause. — A form of life so extremely minute that it is capable 

 of passing through the pores of the finest porcelain filter is the 

 cause of hog cholera; accordingly, it belongs to the group of 

 disease-producing agents known as filterable viruses. The 

 virus of hog cholera can be propagated only in the blood of sus- 

 ceptible hogs. The period of incubation is from five to ten days. 



Symptoms. — Acute hog cholera manifests itself differently in 

 different animals, but in typical cases the following symptoms 

 may be observed: loss of appetite, constipation followed by 

 diarrhea, chills, fever, coughing, gumming of eyelids with a 

 sticky secretion, stiffness, weakness, and paralysis. After death, 

 the skin along the belly and between the fore legs is reddened, the 

 lymph glands congested, the kidneys spotted with little hemor- 

 rhages (Fig. 93), and the lungs often affected with pneumonia. 



Treatment. — There is no cure for hog cholera, but a very effec- 

 tive preventive having some curative value has been perfected in 

 the form of anti-hog-cholera serum. This serum is obtained 



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