184 SWINE DISEASES 



The course of the pectoral form of cholera varies from 

 one to three weeks. The disease frequently terminates 

 fatally within one week, especially when there is extensive 

 lung involvement. A few cases may assume a chronic 

 form and ultimately recover. 



Mixed form. This is the usual form of cholera, and 

 the symptoms evidenced will depend upon the complica- 

 tions. There will be symptoms of digestive derange- 

 ments, such as inappetence, vomition, constipation, and 

 purgation; of pneumonia, such as cough, dyspnea, and 

 nasal discharge; conjunctivitis and cutaneous erythema, 

 tumefactions, and necrosis, the intensity of these various 

 symptoms depending upon the proportionate involve- 

 ment of the various groups of organs. In addition there 

 will be more or less of the symptoms of the septicemic 

 form of cholera, such as reluctance to move, depressed 

 head, arched back, and high temperature. In the acute 

 form of the mixed type of cholera the course is of brief 

 duration, terminating fatally in from one to three days 

 after the first symptoms become evident. 



Diagnosis. From the foregoing description of lesions 

 and symptoms it is very evident that the diagnosis of 

 cholera is rather difficult. There are some laymen, and an 

 occasional veterinarian, who diagnose as hog cholera 

 practically all diseased conditions of swine. Much has 

 been written during the last few years concerning the diag- 

 nosis and treatment of cholera, but the bulk of this lit- 

 erature has come from serum producers, and some of it 

 has apparently been written without sufficient investiga- 

 tion to justify the conclusions. r < 



The symptoms evidenced may cause a clinician to 

 suspect cholera, but the diagnosis should not be based 

 upon symptoms alone. Lesions observed in autopsy may 

 or may not be sufficiently characteristic for one to arrive 

 at a positive diagnosis of cholera. The intestinal lesions 

 that is, the tumefied lymphoid tissue, necrosis, and 

 ulceration that occur so commonly in the intestinal form 

 of cholera may occur in the intestine of swine that are 

 not infected with the filterable virus. Necrosis and ul- 



