COCCIDIOSIS G35 



protoplasm of some coccidia remains undivided with a single 

 nucleus and the cyst has a weak spot, known as the micropyle ; 

 these are the female cells or macrogametes (Fig. 57, B). In other 

 coccidia, the protoplasm having attained maximum growth, 

 divides into a mass of actively motile thread-like bodies, the 

 male elements or microgametes. The cyst-wall then ruptures 

 and the microgametes, penetrating the micropyle of the macro - 

 gametes, fertilise them. In the fertilised macrogamete, which is 

 a zygote known as an " oocyst " and is non-motile, the micropyle 

 closes and the cyst is discharged with the fseces of the animal. 

 On damp ground, the nucleus and protoplasm divide into four 

 spherules. Each spherule becomes elongated, and again divides 

 into two somewhat crescent -shaped bodies, around each pair of 

 which a new, somewhat spindle-shaped capsule forms (Fig. 57, D). 

 In this condition the parasite is very resistant, and may remain 

 alive for six months, undergoing no further change unless intro- 

 duced into another animal. If a young rabbit swallows with 

 its food these crescentic spores, the enclosing capsule is dissolved, 

 and each crescent becomes a rounded amreboid mass, and this 

 again divides up into many crescentic spores. These spores are 

 apparently motile, and enter the epithelial cells of the intestine, 

 gall-bladder, and bile-ducts, where a process of growth and 

 differentiation occurs, and the fully developed parasite is ulti- 

 mately reproduced. 



Coccidial disease, or, as it is sometimes termed, psorospermosis, 

 is occasionally met with in animals, as the sheep, and a wasting 

 disease of young pheasants due to coccidia has been described by 

 McFadyean. 1 Coccidiosis also occurs in grouse and poultry, due 

 to Eimeria avium ; in the latter causing " scour," which may be 

 attended with considerable loss. 



In man, coccidial infections occur in the intestine (Isospora 

 and Eimeria) and in the liver (Eimeria), but are rare and 

 probably non-pathogenic. 2 



Kixford and Grilchrist 3 described two cases of protozoan 

 infection of the skin and organs, accompanied by great destruction 

 of tissue and ending in death. The organisms were spherical, 



1 Journ. Comp. Path, and Therapeut., 1895. 



2 See Dobell, Parasitology, vol. xi, 1919, p. 147. 



3 Johns Hopkins Hosp. Reps., vol. i, 1896, p. 209. 



