PART I. PROTOZOA PARASITIC IN MAN 



ROBERT W. HEGNER 

 1. INTRODUCTION TO THE PROTOZOA 



The Protozoa may be defined as unicellular animal organ- 

 isms usually microscopic in size, but nevertheless exhibiting 

 many activities similar to those of the higher animals, 

 though in a simpler form. They are generally separated 

 into four classes according to the presence or absence of 

 locomotor organs and the character of these when present. 

 The class Sporozoa contains only parasitic species, but the 

 other three classes comprise both free living and parasitic 

 forms. Species parasitic in man occur in all four classes. 

 The following is a brief classification of the Protozoa with 

 examples of human parasites. 



Class 1. Rhizopoda. With pseudopodia. Entamoeba hi8tolytica ) 

 E. coli, Endolimax nana. 



Class 2. Mastigophora. With flagella. Giardia intestinalis, 

 Trichomonas hominis, Trypanosomagambiense, Leishmania donovani. 



Class 3. Sporozoa. Without locomotor organs in adult stage: 

 sporulation occurs. Plasmodium vivax, Isospora hominis. 



Class 4. Infusoria. With cilia. Balantidium coli. 



2. BLOOD INHABITING PROTOZOA OF MAN 

 A. Organisms that Cause Malaria in Man 



1. Classification. The organisms that cause malaria in 

 man belong to the class Sporozoa, subclass Telosporidia, 

 order Haemosporidia and family Plasmodidae. 



The members of the class Sporozoa are parasitic Protozoa 

 without locomotor organs and are further characterized by 

 the method of reproduction known as sporulation. In the 

 subclass Telosporidia the vegetative (trophic) stage precedes 



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