PATHOGENICITY OF TRICHOMONAS 121 



Trichomonas is generally regarded as a harmless parasite, but 

 there seems to be strong evidence that it often causes diarrhea, 

 sometimes very severe and of long duration. Dr. Phihp Hadley 

 and others have recently shown that a species of Trichomonas 

 found in turkeys, and frequently the cause of very severe disease 

 in these birds, is, under ordinary circumstances, quite harmless. 

 When, however, the digestive tract of the bird becomes deranged 

 for any reason, and its vitality and natural defenses presumably 

 lowered, the parasites penetrate certain cells in the intestinal 

 glands, invade the deeper layers of the intestinal wall and begin 

 to attack the tissues themselves. As expressed by Dr. Hadley, 

 " Having experienced its first taste of blood its whole nature is 

 changed; it becomes another animal, raging through the tissues 

 impeded by no protective action that the host organism is able 

 to muster to the defense. Here then we must recognize Tricho- 

 monas as a cell parasite, an organism that has the power to 

 actively invade living cells and to bring about their destruction." 

 Furthermore the parasites substitute, at least to a large extent, 

 absorption of liquid food by osmosis for the ingestion of solid 

 particles, such as bacteria, through the cytostome. Whether 

 or not the Trichomonas of other animals are likewise capable of 

 altering their habits is unknown. They do not cause such severe 

 diseases in other animals as they do in turkeys, but that they 

 become more distinctly pathogenic at some times than at others 

 is a well-substantiated fact. Epidemics of diarrhea and mild 

 dysenteric symptoms in man apparently caused by Trichomonas 

 have been reported from Peru, Brazil, China, South Carolina 

 and Indiana, and it is probable that the parasite is at least mildly 

 pathogenic wherever it occurs, tending to aggravate other in- 

 testinal ailments if not causing them directly. A case has re- 

 cently been reported of an Oriental who was suffering from a 

 foul-smelling decay of the jaw, accompanied by pains in the 

 joints, in which numerous Trichomonas were found in the jaw 

 lesion. After treatment with emetin there was rapid improve- 

 ment, which suggests that Endamoeba may also have been present. 



No specific drug for use against Trichomonas has yet been 

 found. Methylene blue in weak solutions is absorbed by the 

 parasites and causes them to become round and quiet. Castellani 

 recommends taking methylene blue both by mouth and by means 

 of an enema, i.e., irrigation of the large intestine. With this 



