MORBID ANATOMY 



371 



blood of any of the three respective equines ; the immune 

 horse-blood produces the severest reaction, the immune mule- 

 blood causes little reaction, and so does the immune donkey- 

 blood. 



The period of incubation is stated by Theiler to be 21 days. 



§ 285. Symptoms. An acute and chronic type are 

 recognized. The acute type begins with a high temperature. 

 There is jaundice, appearing first in the eyes. Death follows 

 rapidly, often at the time of the maximum temperature. In 

 the chronic cases the symptoms are prolonged. 



The duration of the disease is from a few to several days. 



§ 286. Morbid anatomy. The animal is emaciated. 

 The blood is said to be thin and watery. The conjunctival 

 subcutaneous tissue is of a yellowish color. The muscles are 

 of a reddish brown. All of the tissues are anemic. The 

 spleen is very large. Theiler has found the spleen to be twice 

 the normal size. The lymphatic glands, especially those 

 of the spleen, liver and kidneys, are tumefied and often hemorr- 

 hagic. The liver is yellowish in color and engorged with 

 blood. The bile capillaries are distended. The mucosa of the 

 digestive tract is pale, or sprinkled with reddish areas. The 

 glands in the thorax are enlarged and infiltrated with a gela- 

 tinous substance. Occasionally there are ecchymoses on the 

 lungs and heart. The heart muscle, pericardium and valves are 

 frequently infiltrated with a gelatinous substance. The blood 

 clots are soft. The exuded serum is of a yellowish brown 

 color. The parasites are found in all parts. Death usually 

 follows an acute attack. 



§ 287. Differential diagnosis. Equine malaria is to be 

 differentiated from (i) Brustsfuche, (2) Nagana, and (3) 

 anthrax. In the last two named diseases the finding of the 

 specific organisms will determine the diagnosis. The finding 

 oiXhtpiroplasina^iW distinguish it irom Brustseuche. 



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