254 



INFECTIOUS ENTERO-HEPATITIS 



maladv is of more than ordinary sienificance to those ensraeed 



-CD O O 



in the turkey industry. 



§ 191. Etiology. In 1895, Smith described a micro- 

 organism belonging to the protozoa which he found to be 

 associated directly with the disease process. He designated it 

 Amcvba meleagridis. In those cases in which the disease was 

 recent, or at its height, the parasites were very numerous in 

 the affected tissues, while in those in which the disease process 

 was far advanced and associated with degenerative or regen- 

 erative changes, the parasites were found with difficulty. 



The most fre- 

 quent appearance pre- 

 .sented by the para- 

 sites is that of round 

 homogeneous bodies 

 with a sharply de- 

 fined, single-con- 

 toured outline. With- 

 in these bodies and 

 situated some what 

 eccentric ally is a 

 group of very minute 

 granules, probably 

 representing a nuclear 



structure. Thev vary 



, . ' . Fig. 63. Ama-ba meleagridis. (/) Iso- 



somewhat lusize,,. 1 \ ■ i j. u ,^ 



latea organisms ; {2) single parasites; (j) 



measuring ironi 8 to groups {a) of the amoebcs in mucous membrane 



\0)x in diameter in of a turkey's ccscum. (Smith). 



some cases, from 12 to 14// in others. In the fresh tissues 

 they are distinctl)- larger than the parasites within the tissues, 

 which have undergone the hardening process. The latter are 

 from 6 to 10/^ in diameter. This difference ma}- be due to 

 shrinkage, on the one hand, and on the other to a slight flat- 

 tening of the bodies by pressure in the fresh preparations. 

 These peculiar homogeneous bodies were found, as a rule, free 

 in the crushed preparations, although occasionally giant cells 

 were detected which contained a number of them. The cell 

 nuclei of the giant cells are not visible in the fresh condition. 



