MICROBIAL DISEASES OF MAN AND DOMESTIC ANIMALS 889 



In Europe, Eimeria stieda (Coccidium cuniculi) sometimes causes an 

 enteritis of cattle; in East Africa, a coccidium causes a serious disease 

 of cattle. Other coccidia kill many young pigeons, grouse, and 

 chickens. Coccidia have been found in the liver and intestinal tract of 

 man. 



Coccmiosis OF RABBIT'S 



Eimeria stieda Lindemann, 1865 

 Syn.: Coccidium cuniculi 



. The coccidium causing this disease is the best known of the coccidia 

 infecting mammals. 



This coccidium is parasitic within the epithelial cells of the intestine and within 

 the epithelium lining the bile ducts. Adult, asexual forms measure from 20;* to 

 50M in diameter and they produce from 30 to 200 merozoites. The merozoites infect 

 other epithelial cells where they may again multiply asexually or they may develop 

 into male and female forms destined to multiply sexually. One of the micro- 

 gametes, produced by a microgametocyte, fertilizes a macrogamete and an oocyst 

 is developed. Within the oocyst a number of sporoblasts form, which contain two 

 spores each. The oocysts are passed with the faeces and if they are ingested by a 

 suitable host the spores are set free, when the cyst reaches the intestine, and a 

 new infection is commenced. 



Since the cells parasitized by the coccidia are destroyed, it is evi- 

 dent that a severe infection may do a great deal of harm and interfere 

 with the functions of both intestine and liver. The disease may be 

 limited by making it impossible for uninfected animals to come into 

 contact with the droppings of infected stock. 



AVIAN COCCIDIOSIS 



Coccidium infection is of frequent occurrence among birds, and es- 

 pecially those of domestic varieties, without causing serious symptoms. 

 It is known, however, to cause severe epidemics in certain species, 

 and when present in milder form should be regarded as antagonistic 

 to health. Entamceba meleagridis the organism of " Black head" in 

 turkeys, from its peculiar relationship to the tissues, has been erroneously 

 regarded as a form of coccidium. 



