PI RO PLASM A CAN IS 



493 



E. In rodents : — • 



6. P. wwm Fantham, 1905 — England. 



7. P. avicularis Wenyon, 1908 — -Sudan. 



F. In monkeys : — ■ 



8. P. piiheci P. H. Ross, 1905 — -Uganda. 



Piroplasma canis Piana and Galli Valerio, 1895. 



Synonym. — Babesia canis Piana and Galli Valerio, 1895. 



In 1895 Piana and Galli Valerio found a characteristic haematozoon in the 

 red blood-corpuscles of a dog which was infested by ticks [Ixodes veduv '.us L.), 

 and which was suffering from fever, weakness, and slight jaundice, after 

 having hunted in marshy localities. This haematozoon occupied 3 to 4 per 

 cent, of the corpuscles, and also occurred free in the plasma. In the cor- 

 puscles the parasites appeared as pyriform bodies, as many as two, three, four, 

 or five in one corpuscle, and showed amoeboid movement. The dog in question 

 recovered, but in other dogs the post-mortem showed fluid blood, congested 

 liver and spleen, with icteric staining of the tissues and necrotic foci in the 

 omentum near the pancreas. Other symptoms noted by them in dogs 

 were haemoglobinuria, anorexia, prostration, and emaciation. 



In 1899 Hutcheon described the disease caused by this parasite as ' malig- 

 nant jaundice ' or ' bilious fever ' in dogs. It is also known as ' malignant 

 malaria,' ' hondziekt^,' and ' malarial fever,' and is said to have often been 

 mistaken for distemper. The disease is by no means uncommon in dogs in 

 the tropics, and should be called * cannie piroplasmosis.' 



Geography. — It is known in Europe, especially in Lombardy and other 

 parts of Italy; also in France. In Africa it is found in South Africa, East 

 Africa, Senegal, and other parts, of West Africa, and also in North Africa, 

 including Egypt. Nuttall suggests, however, that the African Piroplasma may 

 be different from the European, In Asia it is found in India and Ceylon, 



Place and Season. — It appears to be more common in coast towns and 

 districts, and less common in higher inland places. It seems to have a 

 seasonal variation, but this is not properly understood. 



The Parasite. — The life-cycle in the dog has been most carefully studied by 

 Nuttall and Graham-Smith. 



In the fresh blood it is noted that the infected corpuscles are pale and 

 enlarged, and contain irregular, dark-coloured, pear-shaped bodies, possessing 

 a central refractive portion. Amoeboid or globular non-motile bodies may 

 be noted, and also many free forms. 



In specimens stained by Leishman's method the parasites seem to consist 

 of a blue-coloured cytoplasm, with a delicate vacuolated or trabecular struc- 

 ture centrally, but more condensed around the periphery. This cytoplasm 

 may contain a single homogeneous nucleus, which has a vivid red colour, and 

 is often connected by a thin strand with a loose mass of chromatin, which is 

 situated near the blunt end . The parasite contains a vacuole. 



Schizogony. — A free pyriform parasite (pyriform stage) enters a normal 

 red blood-corpuscle and becomes rounded (ring stage) in shape, while the 

 loose mass of chromatin is drawn near to the original nucleus, where it con- 

 denses. Finally it fuses with that nucleus, forming a single chromatin mass. 



The parasite now throws out pseudopodia and appears as an amoeba 

 (amoeboid stage), and the chromatin subdivides into two unequal masses, 

 connected with a thin strand , 



This amoeboid stage lasts for a long time, at the end of which the parasite 

 enters upon a quiescent stage, in which the vacuole appears in a subcentral 

 position, and the chromatin, which lies along its margin, has its two masses 

 widely separated, though still connected by the thin strand already referred 

 to. The smaller mass has divided into two, making in all three masses of 

 chromatin connected together by chromatin strands. 



Two small symmetrical processes of cytoplasm protrude from the parasite 



