ANIMAL PARASITES 149 



this country, where but little pork is eaten raw. Infec- 

 tion is usually due to eating raw (merely smoked) ham. 



Hookworm. A disease common in Porto Rico and in 

 the Southern States is due to infection with hookworm. 

 This parasite appears to live only in man, and infection 

 usually take's place through the skin, especially in those 

 walking barefooted. The first symptoms are those due 

 to the penetration of the skin by the young worm, and 

 constitute what is known as "ground itch." Subse- 

 quently the parasites enter the intestines and give rise 

 to very characteristic symptoms, chief among which are 

 anemia and laziness. The worm is sometimes spoken 

 of as the "lazy worm." 



Filaria. The disease known as "filariasis" and "ele- 

 phantiasis" is due to infection with a tiny worm which 

 invades the blood and lymph passages. This infection is 

 transmitted by a species of mosquito. 



So far as the nurse is concerned, the description of the 

 mode of infection, as just presented, should suffice to 

 indicate the mode of prevention. 



