60 HOG CHOLERA 



evidence tending either to affirm or deny the pres- 

 ence of hog cholera. Unless there is a definite 

 history of direct exposure the history in itself is 

 not conclusive. 



Symptoms. Unless several animals are sick it 

 is seldom possible to make a positive diagnosis 

 based on symptoms alone, but the experienced ob- 

 server is usually fairly certain of his ground. 

 It is essential to remember that early in an out- 

 break we do not observe the greatly emaciated 

 hog with arched back, straight tail and drooping 

 ears which has been so frequently described and 

 photographed, and which is the product of long 

 sickness. It should also be kept in mind that 

 many of the symptoms observed in acute hog 

 cholera are present in other diseases, and that all 

 of the symptoms that characterize the disease, do 

 not often appear in one animal. Special consid- 

 eration must be given to a restricted number of 

 the more characteristic symptoms. 



In examining a herd for suspected hog cholera 

 one should first see it unaffected by artificial ex- 

 citement, taking care to observe a tendency in 

 individuals to chill and crawl beneath the litter. 

 Then the animals may be tempted from the nest 

 with feed, observation being made for any that are 

 reluctant to move, or that stagger or weave in the 

 hind quarters. The animals that come greedily to 

 the trough but leave for the nest in advance of 



