LEUKEMIA 87 



when the urine clears up and the feces again assume a 

 normal color. The icteric cast of the mucous membranes 

 may persist for a long time after all other symptoms of 

 the disease have disappeared. 



LEUKEMIA 



This disease has only very rarely been reported in 

 horses, being, no doubt, frequently mistaken for other 

 diseases having a similar general course. The actual 

 diagnosis of leukemia in any form is only possible by 

 laboratory methods. 



Leukemia occurs in two forms; first, myelogenous 

 leukemia, which affects chiefly the leukocytes; second, 

 lymphatic leukemia, in which the lymphocytes are chiefly 

 concerned. The etiology is unknown. 



Symptoms. Leukemia affecting horses is said to occur 

 always in a very gradual, insidious manner. There are 

 at first only signs of general debility, lack of endurance 

 and weakness. There may be a degree of pulmonary 

 dyspnea. Later the mucous membranes assume a pale, 

 almost white color. Heart lesions develop, edematous 

 swellings appear in various regions, and the lymphatic 

 glands throughout the body become very much enlarged. 

 Splenic hypertrophy is always present. There may be 

 general soreness in movement, said to be due to involve- 

 ment of bone marrow. 



When the disease has become well established there is 

 a tendency toward hemorrhage, such as epistaxis. The 

 blood which so issues is pale and thin. Death occurs 

 from inanition, cachexia, or from internal hemorrhage. 

 The course of the disease may extend over a number of 

 years. The prognosis is unfavorable. 



Treatment. Leukemia is only rarely treated as such 

 because a diagnosis is not often made of the true eondi- 



