Dr. Holló Ferenc szerk.: Parasitologia Hungarica 3. (Budapest, 1970)
posteriorly to the caecal orifices. My experiments on coecectomized chickens (ined.) have verified that the above intestinal segments and the coecal mucosa served not only as settlements for E.tenella sporozoites, but the coccidium completed its full endogenous development in these sites.Depending on the severity of the infection, inflammatory reactions with petechiae developed not only in the ileum close to the caecal orifices and on the mucosa of the caecal stump, but also in the rectum. The inflam m ation involved no life danger even when the infestation was massive. This was, however, merely an implication as all experimental birds were killed for pathological and histological examination on the 7th-9th days after infection. Perhaps deaths from tenella coccidiosis may have followed later on. Roughly consistent conclusions were deduced by 1EATHEM (1969) from a similar, but more reliable experimental system. In coecectomized chickens, IEATHEM found the schizogonic and gametogonic stages of E.tenella in the final segment of the small intestine close to the caecal orifices as well as in the large intestine. He did not mention the rectal occurrence of these stages . In my further experiments with E.necatrix the telomerozoites released by the schizonts did not find their site of preference, the caecum, in the coecectomized chickens and, therefore, only a few of them developed to gametes in the caecal stump and in the adjacent area, but never settled in the rectum unlike the corresponding stages of E.tenella .These findings clearly indicated that both E.tenella and E.necatrix maintained organ specificity even under abnormal conditions. Organ specificity of this kind is not infrequent among eimerian parasites of the birds belonging to the order Gallif ormes . The pheasant coccidium E .colchici (Norton, 1967) behaves similarly to E.necatrix ,as it undergoes schizogony in the small intestine, whereas the final process of schizogony and gametogony as well, proceeds in the caecum.
