LIVER FLUKES 2Q7 



is hatched out and, gaining the water, swims about actively until it reaches some 

 suitable mollusk (Limnaa truncatula) . By means of a pointed end, it bores its 

 way into the body of the gastropod and in the pulmonary chamber becomes a 

 bag-like structure (the sporocyst) from the germinal cells of which develop a creature 

 with an alimentary canal (redia). The rediae tend to break out of the sporocyst and 

 wander to the liver of the snail. These rediae may give rise to a second generation 

 of rediae. 



From the rediae minute little worms resembling adult flukes in possessing suckers, 

 but differing in the possession of a tail, develop (cercaria).. Having reached maturity, 

 these cercariae leave the rediae, and, as in case of Faseiola hepatica, lose the tail, be- 

 come encysted on blades of grass, to be eaten by sheep and again commence the cycle. 

 The encysted cercariae develop into adult liver flukes. It is probable that with many 

 flukes the cercariae enter some host, as mollusk, insect, or fish, and that it is by eat- 

 ing such animals as food that man becomes infected. Looss thinks it possible that 

 the miracidium of Schistosoma hcematobium may bore its way directly into man, 

 as do the larvae of the hookworm. Manson also suggests that the reporting by Mus- 

 grave of 100 mature lung flukes in a psoas abscess makes it very probable that these 

 parasites entered the body as miracidia. The idea in China is that the infection 

 with the common liver fluke of man is brought about by eating fish. Fluke disease 

 is generally known as distomatosis or distomiasis. 



LIVER FLUKES 



Faseiola hepatica (Dislomum hepaticum). This fluke, while of 

 enormous economic importance by reason of destruction of sheep, has 

 only been reported 23 times in man, and in these instances does not 

 seem to have occasioned marked symptoms. 



It has a cone-shaped anterior projection and is about 1% inches (30 mm.) long. 

 The intestinal canal, as well as the testicles, is branched. These intestinal diver- 

 ticula are well marked in the cone just after the branching from the oesophagus. 

 Diameter of acetabulum about 1.6 mm., of oral sucker i mm. There is a possible 

 importance of F. hepatica in connection with a peculiar affection known as 

 "halzoun." This results from the eating of raw goat-liver, and it is supposed that 

 the flukes crawl up from the stomach and, entering the larynx or attaching themselves 

 about the glottis, produce the asphyxia characteristic of the disease. ^ 



Dicrocoslium lanceatum. This has only been reported seven times in man. 

 The symptoms are unimportant. The fluke is about Yz inch (8 mm.) long, with 

 testicles anterior to the uterus. 



Clonorchis endemicus (Opisthorchis sinensis). This fluke and the 

 C. sinensis are the most important of the human liver flukes. Until 

 recently these flukes were known as Opisthorchis sinensis. 



Looss has separated this genus from Opisthorchis principally by the character- 

 istic of branching testicles those of Opisthorchis being lobed. This fluke is very 

 common in China and Japan in certain sections of Japan 20% of the population 



