220 THE FLUKES 



Planorbis and Limncea, which could very probably act as inter- 

 mediate hosts as well as the species in which the development 

 has actually been observed, are abundant in the United States, 

 and there is great danger that if once introduced, at least in the 

 warmer parts of the country, these blood flukes might become 

 endemic. Careful examination of immigrants from endemic 

 countries and exclusion of Schistosoma-irfiected persons is impor- 

 tant if the infection is to be kept from becoming established. 

 An ounce of prevention in this country is worth a pound of cure. 



Lung Flukes 



In Japan, China, the Philippines, and other oriental countries, 

 a region which seems to be particularly afflicted with fluke dis- 

 eases, there occurs a very serious lung disease caused by a species 

 of fluke, Paragonimus ringeri (westermani) (Fig. 69). It is also 



e*c.c. 



^~:_>- 



FIG. 69. Lung fluke, Paragonimus ringeri. Abbreviations as in Fig. 74. 

 X about 7. (Partly after Looss, partly after Leuckart.) 



found in dogs. In some parts of Formosa fully 50 per cent of 

 the population is infected. A closely allied species, P. kellicotti, 

 occurs in hogs in the United States, and probably in other parts 

 of the world. 



The lung fluke is about half an inch in length, reddish brown 

 in color, and relatively very broad. The adult lives most fre- 

 quently in the lungs of its host, where it produces cavities an 

 inch or two in diameter. The cavities become filled with various 



