INFECTIOUS DISEASES 



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ently of hog cholera, although it is a frequent complication of that 

 disease. Swine plague and infectious necrotic enteritis are distinct 

 disease conditions, although they frequently occur as associated con- 

 ditions. 



Pigs weighing 30 to 50 pounds are probably most frequently af- 

 fected with infectious necrotic enteritis, although it may occur in re- 

 cently farrowed pigs and aged hogs. (The consideration of this 

 condition in recently farrowed pigs will be discussed under the head 

 of "Scour in Pigs".) 



Pig. 90. Insanitary conditions that predisnose to a variety of infections. 

 The conditions shown above are clearly conducive to all kinds of infection. 

 Note the pool of stagnant water surrounded by mud wallows, manure and 

 decaying vegetable matter. 



Breed appears to play no part as regards susceptibility to this dis- 

 ease. Condition of the swine undoubtedly is a factor in susceptibil- 

 ity ; however, shotes in the best of condition become affected. Climatic 

 conditions have little or no influence in the prevalence of infectious 

 necrotic enteritis, although the disease appears to be more common in 

 late spring and early autumn, probably because that is the season 

 when the majority of the pig crop is of the most susceptible age. 

 Sanitary conditions in which the swine are maintained have an in- 

 fluence upon the susceptibility of swine to the infection ; however, the 



