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Biological Therapy 



ETIOLOGY. Hemorrhagic Septicemia is caused by B. 

 suisepticum (B. bipolaris suis). This organism is identical 

 in most respects with those causing the disease in other 

 species. The organism inhabits the respiratory tract of 

 swine and in this manner is normally present in many 

 healthy animals. This fact has caused some investigators to 

 minimize the significance of this organism and its relation 

 to disease. This same form of reasoning might be applied 

 to the pneumococcus, streptococcus, B. tuberculosis and many 

 others which can be isolated from the respiratory tract of 

 healthy individuals. As a matter of fact, none of the bac- 

 teria ordinarily present in the respiratory or intestinal tract 

 has great significance while the resistance of the host is 

 normal. However, when this normal resistance becomes 

 lowered from any cause, any or all of these organisms may 

 constitute a serious menace to future health and frequently 

 cause the appearance of disease. There are certain bacteria 

 whose virulency is so high that their presence is always fol- 

 lowed by disease (as B. tetani). Others there are which may 

 or may not be virulent, depending upon the environment in 

 which they find themselves. Thus B. suisepticum when 

 residing in a host having a high or even normal resistance 

 may be incapable of propagating sufficiently to cause disease, 

 until the animal's normal resistance becomes lowered, when 

 the environment becomes more suitable to the organism, 

 which then propagates unhindered and hemorrhagic septi- 

 cemia results. 



While any devitalizing condition may bring about this 

 result, it is particularly prone to follow exposure to pro- 

 longed wet or cold weather, shipments, hog cholera im- 

 munization and parasitic infestations. 



In the acute stages of the disease the organisms migrate 

 from the respiratory tract and permeate the circulatory 

 system, in which case they may be isolated from the con- 

 gested lymphatic glands and from localized lesions in the 

 lungs and intestines. A few hours after death the organism 

 is readily isolated from the spleen. The location of the 

 organism has considerable significance since a strain iso- 

 lated from the bronchi, trachea or epiglottis undoubtedly has 

 limited significance, whereas the presence of a virulent 

 strain in the blood, glands, subserous hemorrhages, mucosa 

 of the intestines, spleen or even from lung lesions has great 

 diagnostic importance if supported by clinical findings. This 

 is particularly true when the organism is isolated in pure 

 culture and upon animal inoculation proves virulent. 



