CHAPTEE LIIL 



PATHOGENIC SPOROZOA COCCIDIAHEMOSPORIDIA 

 MICROSPORIDIA SARCOSPORIDIA. 



CALKINS defines the subphylum sporozoa as parasitic protozoa 

 without motile organs, but capable of moving from place to place 

 by structural modifications of one kind or other; reproduction, either 

 simple or multiple, but mainly by spore formation, which is either 

 asexual (schizogony) or sexual (sporogony). This subphylom is very 

 rich in genera divided into a number of classes and orders. Only 

 four orders, however, come within the scope of this work, namely: 



A. Coccidia. These are cell-infecting protozoa, which usually 

 reproduce by schizogony and sporogony, thus giving a life cycle with 

 an alternation of asexual and sexual generations. After fertilization 

 the oosphore forms sporoblasts (mother cells giving rise to spores), 

 which may or may not (asporocystea) be covered by a sporocyst 

 membrane, and which may each become transformed into one or 

 several young reproductive spores (sporozoites). 



B. Hemosporidia. These are intracorpuscular blood parasites 

 which may change from a permanent to an intermediate host, or 

 which may be confined to one host. 



C. Microsporidia. The young vegetative cells are more or less 

 ameboid; the spores are very minute, pyriform, with only one capsule, 

 which is invisible in the fresh state. They are intracellular parasites 

 of invertebrates. 



D. Sarcosporidia. These are sporozoa in which the initial stage 

 is passed in muscle cells of vertebrates. 



COCCIDIA. 



Coccidia are all cell parasites; they are found in vertebrate and 

 also in lower animals, such as mollusks and insects. They are para- 

 sitic in the cells of the gastro-intestinal and geni to-urinary tract. 

 They are generally round or oval. The protoplasm does not show 

 a differentiation into endoplasm and ectoplasm. As a rule, it contains 

 granules, which differ in staining affinities toward various stains. 

 The nucleus is usually situated in the centre, is vesicular, and contains 

 in its interior a granule, which has received the name karyosome. 

 Propagation occurs alternately in sexual and then asexual manner, 

 so that a definite, complicated cycle of life is formed. The spores 



