280 



THE ANIMAL PARASITES OF MAN 



in the liver of a mollusc, Katayama nosopJiora. They infected mice 

 by immersing them in water containing liver emulsion and so free 

 cercariae, thus confirming the similar results of Miyairi and Suzuki. 



Habitat. The worm occurs in Japan, China, and the Philippines. 

 The normal host is man and mammals. Cattle, dog and cat are 

 often found naturally infected. Mice can also be experimentally 

 infected. Their seat of election is the portal vein and its branches, 



especially the mesenteric veins. They either 

 swim free in the blood or remain fixed by 

 their suckers to the intima of the vessels. 

 They have also been found in the vena cava 

 and right heart of a cat, but not so far in the 

 vesical plexus. 



Eggs are found in the submucosa and 

 mucosa of the gut, especially the colon, and 

 at times in the serosa and snbserosa of the 

 small intestine, where they give rise to new 

 growths. Occasionally eggs are found in 

 the brain. The life of the worms is at least 

 two years. 



Pathogenic Effects. Anaemia through loss 

 of blood due to worms ; enlarged spleen, 

 toxic in origin (?) ; phlebitis, thrombosis, due 

 to portal stasis ; the eggs, however, cause the 

 greatest mischief. They are carried by the circulation to various 



FIG. 179. Schistosoma ja- 

 ponicum : from dog. Uterine 

 egg. x c. 800. (After Kat- 

 surada.) 



FlG. 180. Schistosoma japonicum : from 

 dog. x c. 800. (After Katsurada.) 



FlG. 181. Schistosoma japonicum : 

 from dog. Egg from fseces. x c. 800. 

 (After Katsurada.) 



