594 



PIROPLASMA CANIS 



trically in the intracorpuscular forms, but in the centre of the para- 

 sites which are found free in the blood plasma. 



The Piroplasma canis, like the bigeminum, reproduces in the 

 interior of red blood corpuscles. According to Nuttall and Smith 

 a small, round, young form is first present. This becomes larger, 

 begins to divide by becoming somewhat saddle-shaped and pear- 

 shaped, with the twin arrangement later on. The twins after being 

 completely divided leave the red blood corpuscles, enter new ones, 

 and repeat the cycle. 



Kinoshita has described an irregular division or budding process 

 which he regards as an asexual multiple reproduction (schizogony), 

 with merozoite formation, as it occurs in malarial organisms. Chris- 

 topher, however, claims that such a mode of division does not occur 

 in piroplasmata, that they divide always into two equal halves, but 

 that subdivision may start before the first division is complete. 



FIG. 211 



Stages in the development of Babesia canis. (After Kinoshita.) A t round discoid parasite 

 in a blood corpuscle; B, ameboid form, with long processes; C, a pair of "mature" gametes; 

 D, a mature "female" gamete; E, a mature "male" gamete; F. a budding form in blood cor- 

 puscles; G, a group of sixteen "young" gametes. 



The most constant symptom in canine piroplasmosis is hematuria, 

 just as in Texas fever of cattle. 



Natural infection is brought about by biting ticks. Several kinds 

 have been named as being the intermediate host of Piroplasma canis, 

 among them Hemophalis leachii, which, however, can only transmit 

 the disease during the mature stage; neither the six-legged larvae 

 nor the eight-legged nymphse can transfer the disease from infected 

 to healthy dogs. 



