314 



SPOROZOA. 



259. Babesia gibsoni (Patton). (Fig. 154.) 



■fPiroplasma tropicus (part), Lingard & Jennings, 1904, pp. 161-5. 

 \Piroplasma gibsoni, Patton, 1910, pp. 274-81, fig. 1. 

 "fPiroplasma tropicus (part), Baldrey, 1910, pp. 572—7. 

 ■fPiroplasma gibsoni, Patton, 1911, pp. 615-21, 1 fig. ; Symons & 

 Patton, 1912, pp. 361-70. 

 Achromaticus gibsoni. Franca, 1917, pp. 221—9. 

 Piroplasma gibsoni, Castellani & Chalmers, 1919, p. 497. 

 Babesiella gibsoni, Velu, 1922, p. 131. 

 Babesia gibsoni, Wenyon, 1926, pp. 1020-1, fig. 422. 

 Piroplasma gibsoni, Symons, 1926, pp. 293-315. 

 fPiroplasma gibsoni, Rau, 1927, pp. 785-800, pis. xxxi, xxxii, 



4 text-figs'. ; Stirling, 1929, pp. 647-53. 

 f Babesia gibsoni, Swaminath & Shortt, 1937, pp. 499-503 ; Ray & 

 Idnani, 1938, p. 265. 



Smaller than B. canis ; young trophozoites rounded, not 

 pear-shaped, and appear as small ring-like forms occupying 

 about one-eighth of the infected corpuscle. Parasites (in 

 films stained with Leishman's or Giemsa's stain) appear 

 as small rings, somewhat resembling the rings of the malignant 

 tertian malarial parasites but very much smaller and staining 



C J> 



Fig. 154. — Babesia gibsoni (Patton). 

 (From Wenyon, after Patton.) 



less deeply. They also differ from B. canis in not showing 

 reticular structure of protoplasm or vacuoles. The protoplasm 

 takes a very faint blue stain, the ring being sometimes made 

 up of a blue-staining periphery and a clear centre. Generally 

 there are two masses of compact chromatin, staining red, 

 one larger and the other smaller, which is situated either 

 near the larger or on the periphery of the ring. Larger 

 ovoid or elongate forms are also met with, though in smaller 

 numbers. Parasite usually excentrically situated in the blood- 

 corpuscle. Usually only one, but sometimes up to five, may 

 be found in a single corpuscle. The infected host-cell generally 

 not altered in shape or size. Sometimes the parasite escapes 

 from the corpuscle, becomes disc-shaped, and after a short 

 while enters another corpuscle. In spleen -puncture smears 

 similar forms are met with, and also very large rings with their 

 chromatin divided into two, three or even four parts. Schizo- 

 gony takes place in the spleen. The parasite, having penetrated 

 a red cell in the spleen, grows and divides into two, four, etc. 

 The daughter parasites are somewhat pear-shaped, and, when 



