810 Xagaiia. 



a time show a chronic course, a sudden aggravation of the con- 

 dition may develop during a febrile attack, whereupon the ani- 

 mals die in a few hours (cerebral embolus). Some cases may 

 be verv acute and in these almost continuous fever is present, 

 the animals emaciate very rapidly, and death ensues after 2 

 or 3 weeks. 



Recovery has so far been observed only very exceptionally 

 (most likely in donkeys). 



In cattle the symptoms, which consist of emaciation and 

 anemia, periodical fever and edematous swellings (especially 

 on the dewlap), sometimes do not become manifest for several 

 weeks, or even months after the infection, and even later they 

 become aggravated only very gradually. The eyes are rarely 

 affected. The disturbance in their movements is only slightly 

 pronounced, while the emaciation may reach a very high degree. 

 Trypanosomes are present in the blood only in very small 

 numbers, and frequently can only be demonstrated by inocula- 

 tion of the blood into susceptible animals. Acute cases are 

 observed only exceptionally. Recovery is more frequent than 

 in horses. 



The disease in sheep and goats manifests similar s^niiptoms 

 to those exhibited by cattle. Parasites are also found only in 

 small numbers. 



In the advanced stages of the disease in dogs, emaciation, 

 labored labial respiration, acute swelling of the lymph glands, 

 shifting edema, especially on the extremities, edematous swell- 

 ings of the feet, incoordination of movements, keratitis and 

 iritis, as well as general falling of the hair may be observed. 



Diagnosis. The sudden and rapidly changing edema as- 

 sociated with febrile manifestations, in the later stages the 

 emaciation, anemia and muscular weakness in association with 

 recurrent fever which progress in spite of good appetite, offer 

 in infected localities a sufficient basis for a probable diagnosis 

 of the disease. Absolute certainty however is only obtained by 

 the demonstration of the trypanosomes in the blood and in the 

 fresh edematous swellings. 



For the examination of trypanosomes a drop of blood should he taken from 

 a superficial vein, mixed with several cc. of physiological salt solution, and the 

 mixture examined in fresh, unstained or stained specimens (see p. 799). 



The iiioculation of blood into small test animals (also dogs) is valuable in 

 the establishment of a positive diagnosis, especially since it accomplishes its pur- 

 pose not infrequently, even in cases of negative microscopical findings. 



Montgomery & Kinghorn recommend puncturing of the swollen lymph glands, 

 as, according to their experience, trypanosomes may frequently be demonstrated in 

 the glandular juice thus obtaine<l, even when the examination of the blood gave 

 negative results. 



Treatment. At present the reports on the results of 

 Ehrlich's chemo-therapy (see p. 802), which has been employed 

 in nagana of domestic animals in Africa are quite insufficient 

 (in sleeping sickness of man which is also prevalent in Africa, 



