PIROPLASMOSIS OF HORSES 595 



PIROPLASMA OVIS. 



Sheep are subject to a disease known as icterohematuria, or hemo- 

 globinuria. It is, like the preceding affections of cattle and dogs, a 

 piroplasmosis. The intracorpuscular organisms were first seen by 

 Babes in 1888, who, however, did not recognize their protozoan 

 nature. Piroplasmosis in sheep was subsequently described by 

 Bonome in Italy, Nicolle in Turkey, Leblanc in France, and Hutche- 

 son in Transvaal. The most marked pathologic changes in piro- 

 plasmosis in sheep are a serous infiltration of the subcutaneous, 

 retroperitoneal, and mediastinal connective tissue, inflammatory and 

 hemorrhagic changes in the gastro-intestinal tract, enlargement 

 and great congestion of the spleen, parenchymatous degeneration and 

 necrosis of the liver, parenchymatous degeneration of the kidneys, 

 and multiple subserous and submucous hemorrhages. The bladder 

 contains a bloody urine. The parasites causing the disease are 

 piroplasmata of the usual shape and structure. Dividing forms can 

 best be seen in juice expressed from the spleen. The anemia caused 

 during the short course of the disease is very profound, and the count 

 of erythrocytes sinks from 8,000,000 to 1,500,000. The mortality of 

 the disease is very high; recovered animals are said to be immune. 

 The disease is spread by ticks. 



PIROPLASMOSIS OF HORSES. 



Besides the infectious anemia in horses, which is a disease evidently 

 due to an ultramicroscopic filterable organism concerning which 

 absolutely nothing is known, anemias in horses due to piroplasma 

 infection have been observed at various times and places. Ziemann 

 claims to have seen intracorpuscular piroplasmata in the blood of 

 horses sick with hematuria in Germany. Hutcheson reported similar 

 findings from Cape Colony. Bordet and Danysz found equine piro- 

 plasmosis in Transvaal. Some authors have claimed that the Plas- 

 modium malarias has also been found in horses, but this is denied 

 by Laveran, who holds that all intracorpuscular parasites found in 

 the blood of horses are piroplasma and none Plasmodium malarise. 

 Some of the later observations on equine piroplasmosis were made 

 by Pallin in India and Robert Koch and Theiler in Africa. The 

 latter distinguishes two types : a mild form, where a diagnosis can only 

 be made by finding a few piroplasmata in the blood, and serious cases, 

 with high fever and marked sickness. The former type generally 

 ends in recovery, the latter in death. The parasites are found in 

 the blood and most abundantly in the spleen. The organisms are 

 generally round, have a diameter from 0.5 to 2.5, and look a good 

 deal like tropical and tertiary malarial parasites. Pear-shaped forms 



