CHAPTER IX 

 TRANSMISSION OF INTESTINAL PROTOZOA 



By 



Robert Hegxer 



The Johns Hopkins University School of Hygiene and 

 Public Health 



INTRODUCTION 



One of the most interesting phases in the life-cycle of intestinal 

 protozoa is that during which they are transmitted from one host 

 to another. It is at this time that measures for prevention and 

 control can most successfully be applied, measures which, from the 

 standpoint of personal hygiene, protect the individual from infec- 

 tion, and, from the standpoint of public health, protect the general 

 population, either rural or urban, from infection. The fifteen 

 species of intestinal protozoa that are usually recognized by proto- 

 zoologists at the present time may be classified as follows with 

 respect to their habitat within the body and the method by which 

 they are transmitted : 



I. Species transmitted by the contamination of food or drink 

 by cysts : 



( a ) I NTESTI N AL A M CEB^ : 



(i) Endamccha histolytica, the organism of amoebic 

 dysentery and amoebic liver abscess. 



(2) Endamooba coli, a harmless commensal living in the 



large intestine. 



(3) Endolimax nana, similar to (2). 



(4) lodama^ba imlliamsi, similar to (2). 



(5) Dientamceha fragilis, similar to (2). 



(b) INTESTINAL FLAGELLATES : 



(6) Chilomastix mesnili, a possible causative organism 



of flagellate diarrhea. 

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