468 CHRONIC INFECTIOUS DISEASES 



Etiology. — ^The cause is supposed to be the Cryptococcus 

 farciminosus, large oval bodies very difficult to stain, found 

 in the discharge from ulcers. In the cases which occurred 

 in Pennsylvania bacteriological investigations failed to reveal 

 the cryptococcus but did show the presence of a sporothrix 

 identical with that isolated from man. Evidently the 

 Pennsylvania outbreak, and very probably the other out- 

 breaks in this country, were not identical with the epizootic 

 lymphangitis first described by Tokishiga (1896) and Pallin 

 (1904) in horses in Japan and India. 



Natural Infection. — ^Evidently occurs through small lesions 

 in the skin. The cryptococcus is probably carried by inter- 

 mediate agents, such as harness, bedding, stable utensils, 

 etc. It is also possible that insects may be carriers of the 

 infection. The disease is most common in cold, damp 

 weather. Asses and mules seem more predisposed than 

 horses. Cattle are very rarely affected. 



Symptoms. — ^The disease usually first attacks the limbs, 

 particularly the f orelimbs, but may also occur on the scrotum 

 or udder or more rarely the body and neck. Usually the 

 disorder originates in a wound or fresh cicatrix. A wound so 

 infected does not heal but is converted into an ulcer with 

 exuberant granulations. From a cicatrix a painful nodule 

 the size of a pigeon's egg forms, which later erupts, discharg- 

 ing a thick, yellow pus. Soon the inflammation involves 

 the lymph vessels, which become swollen, corded, and very 

 painful, and along their course fresh abscesses develop. 

 The abscesses rupture, forming ulcers which heal slowly. 

 The ulcers show a tendency to exuberant granulation, and 

 by confluence are spread and may produce great ulcerous 

 surfaces. The regionary lymph glands are involved in the 

 process; not infrequently abscesses form in them. As a 

 rule the infected limbs swell; particularly about the joints 

 and in the overlying skin superficial ulcers develop. 



In rare instances the morbid process may involve the 

 nasal mucous membrane, on which form white nodules and 

 later ulcers which tend to coalesce. The submaxillary lymph 

 glands are involved and may suppurate. Nasal discharge 

 is rare. Usually the appetite and temperature remain normal. 



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