TRYPANOSOMIASIS 455 



discharge, plaques, and edematous swellings, is very scarce 

 and "difficult to find. Negative evidence, therefore, in this 

 regard would not be convincing. Of diagnostic value are 

 the plaques, nerve symptoms (paralysis), and the marked 

 emaciation of the patient. All breeding horses and asses 

 showing these should be considered suspects. Animal in- 

 oculations (dog, mouse, rabbit) may also be employed. 

 When in the primary stage dourine might be confused with 

 coital exanthema which sometimes looks strikingly like it. 

 However, this is a benign disease, healing readily and 

 leaving behind no permanent scars and is followed by neither 

 plaques nor nerve symptoms. Traumatic lesions of the 

 vagina from excessive copulation (range mares) is character- 

 ized by wounds and ecchymoses (purple patches) rather than 

 by vesicles and ulcers. The mallein, guinea-pig or comple- 

 ment-fixation tests suffice to differentiate between glanders 

 of the sexual organs and dourine. Paralysis due to infectious 

 anemia, forage poisoning, etc., affects geldings as well as 

 stallions and mares. 



Course. — In northern latitudes the course is chronic; in 

 southern usually acute. In some cases the second stage, 

 beginning with the development of the cutaneous plaques 

 follows closely the first stage. The nerve symptoms 

 (paralyses) may not develop, however, until weeks or months 

 later. The duration of the whole attack may extend over 

 one or more years. Obviously any factor which reduces 

 the resistance of the patient (poor care, insufficient food, 

 breeding, etc.), will shorten the duration. Exacerbations 

 and remissions during the course are common. 



Prognosis. — The prognosis is bad. Fully 50 to, 80 per cent, 

 of the animals attacked die. A few recover when in the 

 first stage of the disease, the second stage failing to de- 

 velop. It is doubtful whether cases in the second stage ever 

 recover. 



Treatment. — Internal medicinal treatment (arsenic, atoxyl, 

 bichlorid of mercury, intravenous injections of tartar emetic, 

 arsenophenylglycin, cacodylate of soda, etc.), has been 

 tried with indifferent success in countries permanently 

 infected with dourine. In the United States no attempt to 



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