Pathogenesis. 763 



time. Tlie debris of the cells at the same time cause emboli 

 in the various organs, especially in the kidneys, as a result 

 of which hemorrhages develop, and parenchymatous inflamma- 

 tion is produced in the kidneys (Smith, Betegh), manifested in 

 the presence of albumen in the urine, which exceeds the hemo- 

 globin in quantity. The rapid diminution of the number of 

 red blood corpuscles, and the disturbance in nutrition which 

 is always present, lead finally to death from exhaustion in a 

 large proportion of the cases. 



According to the investigations of Barratt & Yorke, the haemoglobinuria 

 develops in piroplasniosis of dogs as a direct result of the haemoglobineniia only 

 when the blood plasma contains as nmch hemoglobin in solution as 0.5% red 

 blood corpuscles in proportion to the total volume of the plasma. At the same 

 time the red coloration of the urine is pronounced only in a marked and rapid 

 destruction of erythrocytes, while in chronic cases it is usually not observed, as 

 in these the destruction reaches a greater proportion, but develops only gradually. 



Contrary to the above piroplasmosis, hemoglobinuria is 

 not observed in East African coast fever, or in tropical piro- 

 plasmosis, and only exceptionally in piroplasmosis of horses, 

 although a great proportion of the erythrocytes contain the 

 parasites. These affections are manifested in the acute cases 

 tjy more or less pronounced symptoms of a general blood in- 

 fection, and the anemia appears only 

 in the more chronic cases. The 

 cause of the difference in the patho- 

 genic action is at the present un- 

 known. 



Animals which have recovered 

 from an acute attack continue to 

 harbor the respective piroplasma in 

 the red blood corpuscles, even for 

 years, in spite of the apparent re- 

 covery and satisfactory nutrition, al- 

 though only in small numbers ; they 

 may also be present in animals 

 „•«;& ''ciu-otS^XiZK: which, prol^bly on account of their 

 (After Theiier). high resistance, have never shown 



manifest symptoms of the disease. 

 Such animals are constant virus carriers, and may be the cause 

 of the infection of ticks, thereby aiding the spread of the dis- 

 ease among susceptible animals. At the same time they them- 

 selves are usually immune against later infection with the same 

 piroplasma (cattle which have recovered from coast fever are 

 incapable of transmitting the infection). 



Anaplasma Marginale. In America and Africa, in localities in 

 which the piroplasmoses are prevalent, the blood of animals, especially 

 of cattle, which pass through the disease, contains erythrocytes with 

 very small, round or oval, marginal bodies (Fig. 129), staining with 

 the chromatin, the nature and importance of which is still in doubt. 

 Smith & Kilborne described them as peripheral, coccus-like bodies, 



