792 



Piroplasmosis of Doj's. 



chronic course. In these locations hunting dogs usually become 

 affected, which have previously hunted in the forests. 



In Europe the disease has been diagnosed, besides in Italy and France, by 

 Wetzl in Hungary, by Ljubenetzkij and by Dscbunkowsky & Luhs in Russia; 

 Holterbach believes that a disease of dogs which he observed since 1907 in German 

 OflEenburg, should from its clinical picture be considered as a piroplasmosis. Of 

 the tropical countries, excluding South Africa, India and China are especially 

 infected. 



Fig. 137. Piroplasma canis. 

 Stained with methylene blue. 



Fig. 138. Piroplasma canis. 

 Stained after Laveran. 



Etiology. The piroplasma canis (Babesia canis) is mor- 

 phologically closely related to the piroplasma bigeminum (Figs. 

 137 and 138), only that the parasites found in the red blood 

 corpuscles and those in the blood plasma are relatively larger 

 (.7-3.6 ''), and that single blood cells contain more of the para- 

 sites, sometimes as many as 16 individuals. The extracellular 

 ones are roundish, those inclosed in cells are pear-shaped or 

 poly-angular. While living they show an active motility, in 

 which they send out very fine pseudopodia. The homogeneous 

 plasma encloses a spherical or oval nucleus. Propagation, which 

 is especially prolific during the duration of the fever, is, accord- 

 ing to Nocard & Motas, supposed to occur by direct fission, in 

 which the splitting of the nucleus precedes that of the plasma 

 body. 



According to Nuttall & Graham Smith propagation is also supposed to occur 

 by direct fission. They observed free pear-shaped parasites in the blood plasma, 

 actively swimming around, apparently propelled by flagellae, and subsequently to 

 penetrate red blood corpuscles. In these they assumed a spherical shape, sent out 

 pseudopodia, and divided into two pear-shaped bodies, which subsequently separated, 

 slipped out of the blood corpuscles and looked for new erythrocytes. If they failed 

 to find them they died. Kinoshita saw similar phenomena, but believes that the 

 individuals resulting from fission should be differentiated into male, possessing 

 flagellae, and female forms without flagella. 



If the defibrinated blood of affected dogs is mixed with equal parts of physi- 

 ological salt solution and is kept at a temperature of from 24°-27° C, the piro- 

 plasma remain alive for four days, they show similar stages of development (star 

 shapes) to those described by Koch for the piroplasma of cattle in the intestines of 

 ticks (see p. 766) (Kleine, Nuttall). Similar forms were observed by Chris- 

 tophers in the intestines of nymphs and of mature ticks, besides the pear shapes are 

 supposed to penetrate the cells of the salivary glands and the eggs in the body of 

 the tick, where they break up into sporozoites (?), which then leave the body of 

 the tick with the saliva. 



