SCHISTOSOMUM JAPONICUM 



45 



formation, caseation, or necrosis. The walls of the vessels 

 containing the worms are much thickened, so that it is 

 difficult to say whether they are veins or arteries. Accord- 

 ing to the Japanese an endemic disease characterized by 

 enlargement of the liver and spleen with ascites is caused 



t*-~~ 



FlG. 20. A, Schistosomum japonieum. (After Fullerton.j 

 exiremity of male, enlarged. 



B, anterior 



by this parasite. In the early days of the infection there 

 is more or less fever of an irregular type. Kosinophilia 

 is marked in this stage and urticaria is so frequent that 

 the fever was described as " urticarial fever" before the 

 relation to Schistosomum infection was known. It was 

 also in Japan known as Katayama disease. There is 

 usually diarrhoea, and sometimes blood and mucus are 

 passed. Later the fever may cease, and in bad cases 

 organic changes supervene, or the urticarial fever may 



