PATHOGENIC PROTOZOA OF THE MASTIGOPHORA 427 



panosome disease of importance in Europe and in North Amer- 

 ica. 



Distribution. The disease is known from Germany, Austria, 

 France, and southern European countries, northern Africa, western 

 Asia and India, Chile, Java, and several local epidemics have 

 occurred in North America (Illinois, Nebraska, Wyoming, South 

 Dakota, and northwestern Canada). 



Morphology (See Fig. 188). Moore and Bredini, in a study of 

 this trypanosome as it occurs in artificially infected rats, concluded 

 that it passed through certain developmental stages, finally being 

 converted into rounded bodies with two long delicate flagella. 

 The organism, as it occurs in the lesions and blood of the horse, is 

 a slender cell, usually about 25 to 28 // in length. There are no 

 particular differentiating characters between this organism and the 

 ones associated with other trypanosomiases of the horse. The 

 blepharoplast is distinct, the membrane considerably folded, the 

 nucleus central, and the free flagellum about ^ to ^ the length of 

 the organism. Protoplasmic granules are never present. 



Cultivation. Thomas and Breinl have succeeded in cultivating 

 the organism in a modified Novy and MacNeal medium in one 

 trial out of nineteen. 



Pathogenesis. Experimental Evidence. The disease may be 

 transmitted experimentally to the horse, the ass, to fowls, and even 

 to ruminants and apes, according to some observers. The disease 

 occurs naturally only among the equines. 



Character of Disease. The infected animal becomes emaciated, 

 while whitish or chalk-like areas appear in the skin and mucosa of 

 the external genitalia. Ulcers frequently develop, particularly 

 upon the penis. The disease usually runs a chronic course. The 

 animal frequently becomes gradually paralyzed. Recovery is in- 

 frequent . 



Immunity. Animals that recover from the disease are thereby 

 rendered immune to a second infection. They are not, however, 

 rendered immune to infection with another trypanosome, such as 

 that of surra. It appears that an immunity acquired during 

 pregnancy may be transmitted to the offspring. No method of 

 immunization based upon the organism or its products has been 

 developed. 



