CHAPTER XV 



DISEASES DUE TO PROTOZOA 

 Amcebic Dysentery, Malarial Fever 



Besides the infectious diseases due to the smallest 

 form of vegetable life which we know as bacteria, 

 there are several widespread diseases in both men 

 and animals which are caused by animal micro- 

 organisms, known as pathogenic protozoa (sing, pro- 

 tozoon). 



Protozoa are the smallest form of animal life, and 

 like bacteria, are unicellular and of many species, 

 varjdng in size, shape, and methods of reproduction. 



In some species of protozoa the hf e cycle is as simple 

 as that of bacteria, while in others it is extremely 

 complex. A large number are parasitic upon ani- 

 mals and plants, and by their invasions into the 

 bodies of men and animals are the cause of many 

 serious maladies, especially in the tropics. 



A class of protozoan parasites known as Sporozoa 

 are nearly as widely distributed as bacteria. 



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