100 PROTOZOAN PARASITISM 



PREVALENCE AND IMPORTANCE 



Endamoeha coli is by far the most common intes- 

 tinal protozoon. A large per cent of the population 

 of any place, if not the majority, will show it on thor- 

 ough search. It is an indication of the commonness 

 with which the food of man is contaminated with the 

 excreta of his fellow^s. Some believe that virtually 

 everyone harbors this amoeba at some time. 



Whether it may spontaneously disappear from the 

 intestine is unknown. The writer know^s of one per- 

 son who has show^n it on numerous examinations over 

 a period of fifteen years. 



Its particular importance lies in the common con- 

 fusion of it in medical practice with Endamoeha histo- 

 lytica. The writer knows of a number of instances 

 in which physicians have treated and ^^cured" cases 

 of intestinal amoebiasis or amoebic dysentery, so 

 diagnosed, in whom Endamoeha coli was the only 

 amoeba present and in whom it remained after the 



HABITAT AND EFFECT 



Endamoeha coli inhabits the lumen of the first 

 part of the colon in its actively feeding stage. As it 

 passes down the colon it encysts and passes out in 

 the feces, from which it is transferred to a new host 

 by ways previously discussed in the case of Endam- 

 oeha histolytica. In the intestine of its new host 

 it is liberated from the cyst and completes its division 



