308 PROTOZOOLOGY 



Family 10 Trichomonadidae Wenyon 



Genus Trichomonas Donne (? Ditrichomonas Cutler), Pyriform; 

 typically with 4 free anterior flagella; fifth flagellum along the outer 

 margin of the undulating membrane; costa at the base of the mem- 

 brane; axostyle well developed, often protruding beyond the pos- 

 terior end of the body; cysts have been observed in forms inhabiting 

 certain mammals such as T. caviae (Wenyon), but not in the three 

 species living in man; all parasites. Numerous species (Wenrich, 

 1944). 



T. hominis (Davaine) (Fig. 144). Active flagellate, undergoing a 

 jerky or spinning movement; highly plastic, but usually ovoid or 



\( aI 



r 1 t 



Fig. 144. TricJiomonas hominis, X1150 (Kudo). 1, living and 

 2, 3, stained trophozoites. 



pyriform; 5-20/x long; cytostome near anterior end; 4 anterior 

 flagella equally long; fifth flagellum borders undulating membrane 

 which is seen in life ; in degenerating individuals the membrane may 

 undulate, even after loss of flagella, simulating amoeboid movement; 

 axostyle straight along the median line; vacuolated cytoplasm with 

 bacteria; commensal in the colon and ileum of man; found in diarr- 

 hoeic stools. Wenrich (1944) states that in all 20 cases which he 

 studied, some or most of the individuals showed five anterior flagella 

 and two unequal blepharoplasts. Evidently the organisms belong to 

 Pentatrichomonas. 



Since encysted forms have not yet been found, transmission is as- 

 sumed to be carried on by trophozoites. According to Dobell (1934), 

 he became infected by an intestinal Trichomonas of a monkey 

 {Macacus nemestrinus) by swallowing "a rich two-day culture" plus 

 bacteria which were mixed with 10 cc. of sterilized milk on an empty 

 stomach. The presence of Trichomonas in his stools was established 

 on the 6th day by culture and on the 13th day by microscopical 

 examination after taking in the cultures. The infection which lasted 

 for about four and a half years, did not cause any ill effects upon 



