ANIMAL PARASITISM 



743 



live as parasites, but the great majority of parasites belong to one 

 of these four phyla : Protozoa, Platyhelminthes, Nemathelminthes, 

 and Arthropoda. 



To cerebrospinal fluid cau&'ing steeping 

 sickness and dealh. 



Transmission by 

 bite of tsetse fjy. 



^ Man, Antelope, etc. 



Xrypanoaomes 



in human blood causing 

 Trypanosome jever- 



Transmission by bite 

 of tsetse fly. 



Tsetse Fly 



n salivary glands 

 'or re- infection. 

 -•' 30"- day) 



Critbidial ^orms in. 

 salivary glands 

 (2, or »3 days later) 



Forms in miclgut,(V6/ 

 after infective meal). 



(lewly arrived form in 

 .salivary gland. 

 (I2«'lto,20"'days.) 



Long slender forms In pnoventriculus. 

 ^about IO*''tol5*''dcry3) 



Fig. 387. — Life history of Trypanosoma gamhicnse. (Reprinted by permission 

 from Introduction to Human Parasitology by Chandler, published by John Wiley 

 and Sons, Inc.) 



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|r. 



Ml 



'4 



Protozoa. — Of the four classes in this phylum, one, Sporozoa, is 

 entirely parasitic; the other three (Sarcodina, Mastigophora, In- 

 fusoria) also contain a number of parasitic forms. Examples of 

 parasitic Sarcodina are the three common human amoebae, Endor- 



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S' 



