THETLERIA PARVA 



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in the spleen or lymphatic glands, in which they grow and become the multi- 

 nucleated masses, and so complete the process ot schizogony. 



Sporogony. — After a time merozoites are produced with a different nuclear 

 structure; these multiply and produce the gametocytes, which, penetrating 

 into the red blood cells, appear in the peripheral circulation. The micro- 

 gametocytes are the bacillary forms, and the rounded or pear-shaped forms 

 are the macrogametocytes. In Eurhipicephalus these come out of the 

 corpuscles, and the male forms creep about like little amoebae, while the 

 nucleus undergoes reduction, forming the microgamete. In a similar manner 

 the macrogamete is formed. Copulation takes place, and a zygote in the 

 form of an active ookinete is formed, which enters the salivary glands and 

 breaks up into sporozoites. 



Fig. 164. — Life-Cycle of Theileria parva (Theiler, 1903). 



(After Gonder, from the Report of the First Expedition of the Harvard School 

 of Tropical Medicine to South America in 191 3.) 



It is spread by Eurhipicephalus appendiculatus Neumann, by the nymphs 

 and the adults. 



Cultivation. — Miyajima states that he has cultivated the parasite in broth, 

 producing trypano some-like bodies, but this has not been confirmed. 

 Inoculation. — It cannot be inoculated successfully. 

 Incubation. — Fourteen days. 



Symptoms. — The symptoms produced are very similar to those caused by 

 P. higeminum, but there is very little anaemia and no haemoglobinuria. 

 Mortality. — The mortality is about 90 per cent. 



Post-Mortem. — The autopsy shows oedema of the lungs, inflammation of 

 the lymphatic glands, and infarcts in the lungs, liver, and kidneys. 



Theileria mutans Theiler, 1907. 

 Synonym. — Piroplasma mutans Theiler, 1907, 



This Piroplasma is found along with P. bigemina, in cattle in the Transvaal, 

 and produces forms like Theileria parva, but distinguished by being ingculable. 

 It is not known how it is spread. 



