582 PIROPLASMA BOVIS 



mode of infecting cattle was by transmission through biting and blood- 

 sucking ticks. Their work was afterward confirmed in other parts 

 of the world in the observation of identical or at least similar blood 

 infections of cattle in Finland, Italy, Australia, Africa, Germany, 

 and South America. Smith and Kilbourne first named the blood 

 parasite found in Texas fever pirosoma; later the organism was called 

 apiosoma. Since, however, these family names had previously been 

 applied to other organisms, the name was subsequently changed to 

 Piroplasma bigeminum, which means pear-shaped protoplasmic 

 twin bodies. 



Pathologic Anatomy. If the disease has taken a very rapid course 

 the carcass may be full and rounded; if the animal has been sick 

 for a number of days there is generally emaciation and evidence 

 of rapid loss of weight. In fat cattle which have contracted the 

 disease and died from it during or shortly after transit a deep orange 

 hue of the subcutaneous and other connective tissues is one of the 

 most characteristic postmortem findings; frequently the muscles 

 show a deep mahogany yellow tint. In thin milch cows and Southern 

 stock cattle the icteric discolorization of the tissues is often absent. 

 The degree of icteric discolorization of the tissues depends upon the 

 number of red blood corpuscles which have been destroyed by the 

 infecting parasites and the amount of hemoglobin which has first 

 gone into solution in the blood plasma and has subsequently been 

 deposited in the tissues or excreted by the urine. Ticks are often 

 found adhering to the skin of an animal dead from Texas fever, and 

 here and in places where they have fallen off edematous and hemor- 

 rhagic patches are seen. 



Microscopic examination of the blood shows a more or less 

 marked diminution of the number of red blood corpuscles (oligo- 

 cythemia). The decrease in red blood corpuscles from a normal of 

 about 7,000,000 may be down to 2,000,000 or even much less. If 

 properly studied and examined with a high power, numerous red blood 

 corpuscles show the specific cause of the disease, the piroplasma. 



The heart often shows subpericardial and subendocardial petechiae 

 and ecchymoses; occasionally the myocardium shows cloudy swelling 

 and fatty degeneration. The lungs are at times somewhat congested, 

 and may likewise show small hemorrhagic spots. The peritoneal 

 cavity may show a slight amount of yellowish serum. The spleen is 

 very much enlarged, of a dark brown color, and the pulp very soft. 

 The liver is enlarged, and shows a mottled appearance on the cut 

 surface; the centres of the lobules are yellowish, the periphery reddish. 

 Frequently the whole liver shows an icteric color. The bile ducts 

 are much congested with thickened bile and stand out as markedly 

 as if they had been artificially injected. The gall-bladder is distended 

 and filled with thickened bile, the appearance of which has been 

 likened to masticated grass. The kidneys show hemorrhagic and 

 edematous congestion and parenchymatous degeneration with widen- 



