68 MANUAL OF HUMAN PROTOZOA 



digestive tracts of various birds are often infected by Ei- 

 meria and Isospora. English sparrows are frequently hosts 

 for Isospora lacazei Labbe (Fig. 15, 3). The oocysts are 

 ovoid and measure 18.5-30n long. They contain two spores 

 when mature as in the case of /. hominis (p. 47). Drinking 



1 4 m/i\ 



y 



Vv 



Fig. 15. Coccidian oocysts found in the stool. X 1150 (1, 2, modified after 

 Thomson and Robertson; 3, original). 



1. A fresh mature oocyst of Eimeria sardinae. 



2. A fresh mature oocyst of E. clupearum. 



3. A fresh mature oocyst of Isospora lacazei. 



water contaminated with the droppings of infected birds 

 may introduce the occysts in the faeces. 



Yeasts and molds. These are exceedingly common in 

 the faeces. Yeasts are spherical, ovoid or ellipsoidal bodies 

 and measure about 5-15u in diameter. Surrounded by a 

 distinct membrane, the cytoplasm contains one or more 

 refractile granules and a vacuole. Yeasts must not be con- 

 fused with the cysts of Endolimax nana. Mold spores some- 

 times simulate also protozoan cysts under low power ob- 



