454 INFECTIOUS DISEASES DUE TO PROTOZOA 



being dragged; peroneal nerve, causing knuckling in the hind 

 fetlock and stumbling behind; the obturator nerve, to spread- 

 ing of the gait behind with abduction of the limbs; oculo- 

 motor nerve, to paralysis of the upper eyelid; pudic nerve, to 

 paralysis of the penis. Naturally not all of these paralyses are 

 noted in any one case, but in practically every case some of 

 them, especially those involving the hindlimbs, will be 

 observed. Associated with the peripheral paralysis symp- 

 toms of hyperesthesia are often present. Many patients are 

 extremely sensitive when the skin is touched or pricked with a 

 pin. In some cases if the back be stroked the horse suddenly 

 arches it downwardly and seeks to evade the examiner. 

 Quite frequently, during rest, the animal may show cramp- 

 like contractions of the muscles of a leg, holding the member 

 in the air (as in "straw cramp"). Not infrequently atrophy 

 of paralyzed muscular groups follows. While in stallions 

 the genesic instinct is well preserved, on account of the 

 partial paralysis of the penis which prevents complete 

 erection of the organ, they are unable to serve mares. 



Spinal paralysis is not a common complication, although 

 some patients become completely paralyzed behind. 



An important symptom of the secondary stage is marked 

 emaciation. In some instances the patients emaciate to 

 skeletons, losing fully 50 per cent, of their normal weight and 

 presenting a peculiar tucked-up appearance of the flanks. 

 As further symptoms may be noted swelling of the lymph 

 glands in the throat and inguinal regions and decubital 

 gangrene of the skin. Occasionally, nasal catarrh, con- 

 junctivitis, fibrinous pneumonia, arthritis and tendovagin- 

 itis, iritis and albuminuria are observed. The temperature 

 often remains normal throughout the attack, although an 

 atypical fever is not infrequent. The appetite of the patient 

 is usually well preserved. 



Diagnosis. — In isolated cases with uncertain history the 

 diagnosis from the clinical symptoms alone is often difficult. 

 In the United States where no other trypanosome disease 

 among horses is known, the microscopic determination of the" 

 Trypanosoma equiperdum is clinching. However, in our 

 climate this protozoon, which exists in the urethral or vaginal 



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