INFECTIOUS DISEASES. 89 



Give the symptoms. 



It is said to appear after rainy seasons. There is fever de- 

 noted by a rise of temperature (102°-104° F). The fever is 

 more or less continuous with exacerbations and remissions which 

 is typical of the disease. 



There is an appearance of urticarial swellings on various parts 

 of the body and petechial spots on the visible mucous membranes 

 which are pale at first and later yellow. There is emaciation which 

 is rapid, associated with great weakness and symptoms of per- 

 nicious anasmia. 



As these paroxysms of attacks continue, the symptoms become 

 more severe with each attack, the animal gets weaker, the tem- 

 perature higher, the pulse more rapid and weaker, the respirations 

 forty to sixty per minute, ulcers form on the mucous membranes, 

 and the bowels, which were costive at first, later become loose. 



When death approaches, the temperature rises, heart clots 

 form, the stomach becomes perforated and the animal dies from 

 heart failure, general debility or shock. 



What is the pathology and lesions? 



There is rapid destruction of the red blood cells by the organ- 

 isms. The body is emaciated, the liver, spleen and lymphatics are 

 enlarged. Petechial spots are found on the various internal organs, 

 which are pale. Ulcerations are found in the stomach. The 

 mucous membranes may have a yellowish cast. The oedema is of 

 a yellowish jelly-like consistency. 



How is surra diagnosed? 



It is diagnosed by fever which is remittent, petechial spots on 

 the visible mucous membranes, subcutaneous oedema, rapid ema- 

 ciation and debility, together with the presence in the blood of 

 the Trypanosoma Evansi. 



What is the differential diagnosis? 



Surra may be mistaken for anthrax, dourine, nagana, mal de 

 caderas, but the symptoms and the finding of the special trypan- 

 osoma by the microscope will be sufficient to differentiate it. 



If the Trypanosoma evansi is not found by the first examina- 

 tion, daily examinations should be made until found. The remit- 

 tent character of the disease makes it possible that the Trypanosoma 

 would not be found at every examination. 



