586 PROTOZOOLOGY 



day, after which it disappeared completely. Oocysts were discharged 

 regularly since the 9th day for 32 days. About a month after the 

 cessation of oocyst-production, the person ingested again some 2500 

 cysts, but no infection resulted, which the two authors attributed to 

 the immunity produced during the first infection. Another volunteer 

 showed a similar course of infection. The symptoms disappeared 

 without medication after the termination of oocyst discharge. Thus, 

 the coccidiosis of man appears to be a self-limited one. Attempts to 

 infect common laboratory animals with this coccidian have so far 

 failed (Foner, 1939; Herrlich and Liebmann, 1944; Rita and Vida, 

 1949). History (Dobell, 1919); human species (Dobell, 1926); inci- 

 dence (Magath, 1935; Barksdale and Routh, 1948). 



I. bigemina (Stiles) (Fig. 251, g). In the gut of cat and dog; oocysts 

 10-14/* by 7-9/x. 



I. rivolta (Grassi) (Fig. 251, h). In the gut of cat and dogs; oocysts 

 20-25m by 15-20/*. 



I. felis Wenyon (Fig. 252, a). In cat and dog; oocysts 39-48/* by 

 26-37/*. 



I. suis Biester. In swine faeces; oocysts subspherical, about 

 22.5/* by 19.4/*; sporulation in 4 days. 



I. lacazii Labbe. In the small intestine of passerine birds (spar- 

 rows, blackbirds, finches, etc); oocysts subspherical or ovoidal, 

 18.5-30/x by 18-29.2/*; spores, 16.5-18.5/* by 10.3-12.4/*; heavily in- 

 fected sparrows show definite symptoms of infection; sporulation in 

 24 hours (Henry, 1932b). Sparrows and other common small birds 

 have been known to be free from Eimeria infection, while the barn- 

 yard fowls are seldom infected by Isospora (Boughton, 1929). Sig- 

 nificance of size variation in oocysts (Boughton, 1930; Henry, 1932b) ; 

 development (Chakravarty and Kar, 1944). 



I. buteonis Henry. In the duodenal contents of several species of 

 hawks: Buteo borealis, B. swainsoni, Accipiter cooperii, and Asio 

 flammeus; oocysts irregular in form with a thin wall, 16-19.2/* by 

 12.8-16/*: spores 9.6-13/* by 8-10.4/* (Henry, 1932b). 



I. Ueberkiihni (Labbe) (Fig. 252, b). Oocyst about 40/* long; in the 

 kidney of frogs. Development (Noller, 1923). 



Genus Cyclospora Schneider. Development similar to that of 

 Eimeria; oocyst with 2 spores, each with 2 sporozoites and covered 

 by a bi-valve shell. 



C. caryolytica Schaudinn (Fig. 252, c). In the gut of the mole; 

 sporozoites enter and develop in the nuclei of gut epithelial cells; 

 oocyst oval, about 15/* by 11.5/*. Development (Tanabe, 1938). 



Genus Dorisiella Ray. Zygote develops (without becoming oocyst) 



