Biological Tiierapy 



141 



SYMPTOMS. The onset of this disease is generally sud- 

 den. Animals which were apparently healthy one evening 

 may be decidedly sick the following morning. In this respect 

 the onset differs from that seen in hog cholera, in which case 

 the disease develops slowly and progressively. The inci- 

 dence of disease is not as high as in hog cholera since it may 

 not exceed twenty to fifty per cent and some animals appar- 

 ently recover spontaneously and quickly, which is not the 

 case in cholera. 



Respiratory symptoms are pronounced with the appear- 

 ance of a marked labored breathing, referred to as "thumps," 

 which is in reality a normal inhalation with a short, snappy 

 exhalation. Nasal discharge is generally apparent and may 

 be unilateral or bilateral. This is mucous in type, tending 

 to become ropy and creamy in color. In many cases a char- 

 acterisitc and perisistent cough is manifested. Lachryma- 

 tion may be present in varying degrees. Prostration may be 

 marked from the start or may be only moderate in type. 



Except in most marked cases the animal retains its de- 

 sire for food and does not bury itself in the bedding, which 

 is in marked contrast with cholera-sick swine. The knuck- 

 ling at the hocks and straightening of the ankles so charac- 

 teristic of cholera pigs is not observed, but this is generally 

 replaced by a profound weakness accompanied by stagger- 

 ing or incoordination. However, this does not resemble the 

 knuckling seen in cholera but is that present in any weak- 

 ened animal. 



The temperature may rise rapidly and shows a tendency 

 to fluctuate rather than to remain consistently high. Not 

 infrequently the taking of temperatures furnishes a consid- 

 erable surprise since the visibly sick animals show a normal 

 or nearly normal temperature, whereas those which are ap- 

 parently healthy reveal a high temperature. 



Hemorrhagic septicemia is not a highly contagious dis- 

 ease, yet frequently many animals in the same herd are af- 

 fected. This is not surprising since any condition which is 

 responsible for lowering the vitality of one individual un- 

 doubtedly causes the same condition in the majority of the 

 animals in the herd. 



The symptoms may become progressively worse so that 

 any of the symptoms of pneumonia or pleurisy are observed, 

 whereas not infrequently bacteria from the intestinal tract 

 seize the opportunity to cause secondary infection, as a re- 

 sult of which the symptoms of intestinal infection become 

 apparent. 



