214 SWINE DISEASES 



and a depressed center, and are quite characteristic in 

 appearance. 



Symptoms, No definite symptoms have been at- 

 tributed to hepatic necrobacillosis other than general 

 digestive derangement. These cases are diagnosed at 

 autopsy. 



Treatment. The location of the lesions and the 

 nature of the process practically eliminate the possibility 

 of successful treatment. 



Necrotic Spleenitis 



Splenic necrosis is a rather common condition in 

 swine. It may be caused by other agencies than the 

 Bacillus necrophorus, but from investigations thus far 

 conducted it appears that the most frequent cause of 

 necrosis of the spleen is the Bacillus necrophorus. This 

 condition is commonly associated with the use of a 

 contaminated hog-cholera virus. The infection is carried 

 in the blood to the spleen. 



Lesions. The necrotic centers in the spleen are 

 usually encapsulated, the density of the capsule varying 

 with the length of duration of the process. As a rule, 

 the centers are in the form of nodules. They are of a 

 grayish-white color and usually have a depressed center 

 and a raised border. In size these foci vary from masses 

 half an inch in diameter to irregular masses from one to 

 three inches in diameter. There may be only a few 

 centers, but usually there are many; in some instances so 

 numerous are they that it is difficult to identify any nor- 

 mal splenic tissue. The non-encapsulated lesions are 

 dirty-white centers and give the appearance of having 

 been painted in the splenic tissue. 



Symptoms are indistinct, and treatment cannot be 

 applied. 



Vaginal Vulvar and Preputial Necrosis 



Necrotic vaginitis and vulvitis occurs, but is not 

 prevalent. Infection probably gains entrance through 

 abrasions produced at the time of parturition or copula- 

 tion or, more rarely, by means of accidental traumatic 



