494 MAN CONTROLS HIS ENVIRONMENT FOR HEALTH 



lodge in 

 numarn. 

 "muscles 

 Causing 

 trichinosis 



-worm is 

 a Cjfs'Ls 

 in iTiLcscle 

 of pig 



ularly of children, do little or no harm. The Ascaris, a larger 

 roundworm, sometimes infests children but is rarely dangerous to 

 its host. 



The pork worm or trichina (trl-kl'na), however, is a parasite 



which may cause serious injury. It passes through the first 



,. r _~ part of its existence 



as a parasite in a 

 pig or other verte- 

 brate (cat, rat, or 

 rabbit) ; it is en- 

 closed in a tiny sac or 

 cyst, in the muscles 

 of its host. If un- 

 dercooked pork con- 

 taining these cysts is 

 eaten by man, the 

 covering is dissolved 

 off by the action of 

 the digestive fluids, 

 and the living tri- 

 china becomes free 

 in the intestine of 

 man. Here it repro- 

 duces, and the young pass through the intestinal wall into muscles, 

 causing inflammation there and resulting in a painful and often 

 fatal disease known as trichinosis. The government at one time 

 inspected pork for trichina, but since a microscopic examination of 

 meat was necessary and it was impossible to examine all killed hogs 

 in this way, the practice has been discontinued with the result that 

 trichinosis is on the increase. All pork should be well cooked. 



Filaria are small roundworms that cause various tropical dis- 

 eases — the most serious of which is elephantiasis. The parasites 

 possibly enter the body in drinking water and some are probably 

 introduced by the bite of a mosquito. 



imdar=- 

 cookecC 

 por-k is 



< the \v6rrn 

 is freecC by 

 dions-stive/ 

 ° juices 



yoxsng break" / 

 ouft of Vn&jX 

 iritest'inej 



of maix and 

 migrate, 



In what way may poorly cooked pork be harmful to man ? 



Practical Exercise 23. Find out from local physicians if there has ever been 

 a case of trichinosis in your community. If so, try to find out why it occurred. 

 What kind of inspection of meats do you have in your community? 



