238 TEXAS FEVER 



bly a few small exceptional areas, that portion of the country 

 south of the "Texas fever line" which is shown by a red line 

 on the accompanying map but which is changing constantly by 

 virtue of the spread or elimination of the tick. It has been 

 identified with the tick fever of Australia which has become a 

 source of great loss to the cattle industry of that country. 

 Lignieres has identified the disease in South America ( Argen- 

 tine Republic). It is also reported to be identical with a 

 malady affecting cattle along the Danube River, in the Balkan 

 provinces and in Southern Africa. It is restricted, however, 

 to those countries where the climate is not sufficiently severe 

 to destroy the cattle tick during the winter season and where 

 the animals are constantly infested. Cattle (genus Bos) are 

 the only animals which suffer from it. 



§ 182. Etiology. Texas fever is caused by a microor- 

 ganism belonging to the protozoa and named by Smith, the 

 discoverer, Pyrosovia bigeminum.'^ It is generally recognized 

 that Piroplasma 

 is the proper 

 generic term and 

 it is used by 

 writers on the ^^^' 54- Piroplasma bigeminiim in red blood 



corpuscles. 

 protozoa. 



If Texas fever in America, and hemoglobinuria in 

 Roumania are identical, Babes was the first to call attention to 

 the existence of this intra-globular parasite. It seems that 

 Dr. Stiles in 1867 observed this organism but failed to recog- 

 nize its significance. It is found in the blood in cases of 

 Texas fever and it also exists in the blood of immune animals 

 in the tick infested districts. The life history of this parasite 

 is not determined. In the blood of the diseased animal they 

 appear in the unstained, fresh preparation as minute or larger 

 bright bodies which may be from 0.5 to 4.0/Y in diameter 

 according to the form of the disease. In the acute types of the 



*The genus of this parasite has been changed to Piroplasma by Pat- 

 ton and Apiosoma by Wandelleck, to Auuebosporidies by Bonome, and 

 Proteus virulentissimus by Perroncito. Starcovici has named the organ- 

 ism described by Babes as Hematococcus, Babesia bigeminum bovis. 



