224 



THE FLUKES 



which is not used as food and the habits of which give little oppor- 

 tunity for the parasites to gain access to the human body. The 

 disease is said to have increased in Peru, having been introduced 

 there by Japanese and Chinese laborers. If this is true some 

 Peruvian animal, probably a fresh-water crab, must serve as an 



intermediate host. This suggests that 

 the disease if once introduced might 

 flourish in other countries, especially 

 where fresh-water crustaceans are eaten. 

 Lung fluke infection is evidently an- 

 other disease for which a quarantine 

 should be established. 



Liver Flukes 



Although the liver fluke of the sheep, 

 Fasciola hepatica, and other flukes of 

 herbivorous animals are occasionally 

 found in man, they cannot be looked 

 upon as usual human parasites. Adult 

 liver flukes are sometimes accidentally 

 eaten with raw liver, in which case 

 they attach themselves to the mem- 

 branes of the throat, causing irritation, 

 congestion, a buzzing in the ears, 

 difficult breathing, and other quite 

 alarming symptoms. Vomiting to ex- 

 Clonorchis sinensis. x 3|! pel the worms usually gives immediate 



m., mouth in oral sucker; ph., vgjjgf 

 pharynx; gen. p., genital pores; ' 



v. s., ventral sucker; sh. gl., so- There are several species of flukes, 

 called vitteiiine or yolk glands however, which are apparently espe- 



really shell glands; ut., coiled . V . J 



egg-filled uterus; int., intestine; cially adapted for parasitizing carnivo- 

 sp. d., sperm duct; ov., ovary; rous anmia i s an( j w hich are common 



sem. rec., seminal receptacle, ' , 



where sperms for fertilizing eggs human parasites in some countries. 



are temporarily stored; t.,testis; j China th Philippines and Other 



exc. c., excretory canal; exc. p., " 



excretory pore. (After Stiles.) oriental countries are especially afflicted 



by these flukes. The commonest species 



in man is the Chinese fluke, Clonorchis sinensis (Fig. 74) which 

 is found in all of southern Asia from India to Korea. In some 

 parts of Japan about 60 per cent of the population are said to 

 harbor it in their livers, sometimes in hundreds or even thousands. 



exb.o. 



exc. p. 

 FIG. 74. The Chinese fluke, 



