274 



INFECTIOUS DISEASES 



The death rate in hog-cholera varies in the different forms 

 of the disease. The average death rate is about fifty per cent. 



Differential Diagnosis. — The diagnosis of hog-cholera in the 

 field must depend on the clinical symptoms, post-mortem lesions 



and history of tlie outbreak. 

 The history should be that 

 of a highly infectious disease. 

 Abnormal body tempera- 

 tures of a large percentage of 

 the herd indicate the presence 

 of an acute infectious disease. 

 We should then destroy one 

 of the sick hogs and make a 

 careful post-mortem exami- 

 nation (Fig. 80). An early 

 diagnosis of the disease is 

 necessary, as this enables us to 

 use curative treatment when 

 it will do some good, and take 

 the necessary steps toward 

 preventing the sjjread of the 

 ^ jr ^^Ai ^M '^^^' disease to neighboring herds. 



^ ^^Bl^^ — i Intestinal and lung ivorms 



are common in young hogs. 

 The presence of these worms 

 does not always indicate that 

 they are the cause of the sick- 

 ness and death of the animal. Such parasites are injurious and 

 may cause disease, but it is only in rare cases that they cause 

 death. 



" Pig typhoid " is sometimes spoken of as a highly infectious 

 disease involving the intestines. A disease of hogs that may be 

 termed typhus-fever sometimes affects a large number of the 

 hogs in the herd. This disease occurs among hogs kept in small 



Fig. 80. — Carcass of a rholera hog showing 

 (A) different groups of lymphatic glands; (B) 

 kidneys; and (C) ulcer on eeecum. 



