COCCIDIA 497 



The trichomonas hominis Davaine, found frequently in the human 

 alimentary canal, is very similar to the trichomonas vaginalis, but it 

 is smaller and more pear-shaped. This form has been found often in 

 acute diarrhoeas, but no causal relation between it and the pathological 

 process has been shown. 



A similar form has been seen a few times in lung gangrene, aspira- 

 tion pneumonia, and bronchiectasis. 



Lamblia intestinalis (Lambl, 1859), a flagellate belonging to this 

 group, parasitic in the small intestines of mice, rats, rabbits, dogs, cats, 

 and sheep, has also been found occasionally in the human intestines. 

 It is beet-shaped, bilaterally symmetrical, 10// to 21// long and 5/z 

 to 12// wide, possessing flagella 9// to 14// long. Anteriorly this species 

 has a characteristic concavity, the rim of which seems to be contractile, 

 forming a sucking apparatus. The eight flagella of the organism are 

 arranged in pairs : one anteriorly, two laterally, and one posteriorly. The 

 nucleus is situated anteriorly and has a central constriction. The pro- 

 toplasm of the body is thick and hyaline. Contractile vacuoles have not 

 been seen. Schaudinn has recently observed encystment, copulation, 

 and complicated nuclear changes in this organism. 



Infection follows the ingestion of the cysts with unclean food. The 

 parasites fasten themselves to the free surfaces of the epithelial cells by 

 their sucking apparatus, but seem to exert no harmful influence on 

 their hosts. They have been found most frequently in poor children 

 who play often in dirt containing the cysts. Repeated small doses of 

 calomel will cause their disappearance from the feces. 



Coccidiomorpha. 



Class: Sporozoa. 



Subclass : Telosporidia. 



Order : Coccidiomorpha. 



Suborder: Coccidia. 



Coccidium cuniculi (Rivolta, 1878). 



The coccidium cuniculi is a frequent parasite of the rabbit. Young 

 rabbits are especially susceptible, and extensive epidemics may occur in 

 breeding houses. The symptoms are fever, diarrhoea, yellowish mucous 

 discharge from the nose and mouth, and progressive wasting. The 

 liver is much enlarged and shows throughout its substance variously sized 

 gray- white tubercles, generally surrounded by a capsule, and containing a 

 slimy mass of degenerated host cells, in which are embedded the parasites. 

 The parasites are also found in the feces and in the epithelial cells of 

 the intestines, gall-ducts, and liver. The acute stage of the disease 

 lasts about three weeks. The contents of the coccidial tumors in animals 

 that have withstood the infection may later be emptied, leaving only a 

 mass of cicatricial tissue. In such animals the oocysts may remain for 

 a long time in the gall-bladder and intestines, and by passing out gradu- 

 ally with the feces may provide a source of infection for other animals. 

 The infection is carried by food soiled with cyst-containing feces. The 



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