78 PROTOZOAN PARASITISM 



petent experienced men that there is a chronic low- 

 grade disease, of devitalizing quality but diagnosable 

 only on finding the amoeba. 



There is much yet to be learned about intestinal 

 amoebiasis. 



ACUTE AMOEBIC COLITIS (aMOEBIC DYSENTERY) 



The acute phase of the disease has long been known 

 as tropical dysentery. Although much more common 

 in hot countries it is occasionally seen in other cli- 

 mates, in which it is more apt to occur in the summer. 

 That the climate is directly related has not been de- 

 termined. Certain tropical and subtropical countries 

 are more prolific of intestinal amoebiasis because of 

 hygienic conditions. Other conditions in hot coun- 

 tries are probably related to the production of these 

 acute attacks, the devitalizing heat and humidity, 

 possibly the food. Certain it is that intestinal amoe- 

 biasis in temperate or colder regions does not show 

 this phase as commonly, even relatively. 



There seems to be no proof that there are strains 

 of the amoeba of different degrees of virulence, al- 

 though some experimentation may have so indicated. 

 In fact the work of Walker and Sellards (1913) is defi- 

 nite evidence against variations in virulence among 

 different strains. 



The resistance of the host to the infection appears 

 to be of more concern, although as to just what is in- 

 volved in that resistance we have little knowledge. 



