3l8 READINGS IN BIOLOGICAL SCIENCE 



Stage of the pork tapeworm was of rather common occurrence in swine, 

 the epileptiform symptoms being due, of course, to the lodgment of the 

 cysts in the brain and other parts of the central nervous system. 



Under federal meat inspection swine carcasses showing a light infestation 

 with tapeworm cysts are passed for sterilization, which means thorough 

 cooking at a temperature more than adequate to destroy Uf e in these para- 

 sites; if the infestation is moderate or excessive the carcass is condemned. 



For many years it was assumed that the rarity of the pork tapeworm in 

 man and swine in this country was due to the fact that the American people 

 were not in the habit of eating rare or raw pork, a habit which is well 

 established among the people of certain countries of Europe. Unfor- 

 tunately, in the light of the evidence to be presented in connection with 

 the next and final topic, trichinosis, this assumption does not appear to af- 

 ford the entire explanation. Federal and other competent meat inspection 

 offer the public the greatest measure of protection against the pork tape- 

 worm. The importance of cooking pork thoroughly will be discussed in 

 connection with trichinosis. Thorough cooking of pork will absolutely 

 preclude the possibility of infestation with a tapeworm that is very dan- 

 gerous to human health. 



TRICHINOSIS 



Trichinosis is a disease of human beings, swine and other animals. The 

 parasites which produce this disease are small cylindrical worms, known 

 to zoologists as Trichinella spiralis and commonly known as trichinae; 

 these parasites occur in a great variety of carnivorous and omnivorous 

 mammals. So far as human trichinosis in this country is concerned, only 

 swine need be taken into consideration, since practically all the known 

 cases of human trichinosis in the United States that have been definitely 

 traced to their source were shown to have resulted from the consumption 

 of raw or undercooked infested pork or to the consumption of inade- 

 quately cooked or cured meat food products containing infested pork 

 muscle tissue. A few cases of trichinosis have been traced in this country 

 to the consumption of jerked bear meat, and in Germany this food was 

 responsible for a serious outbreak of trichinosis several years ago. 



Unfortunately, pork that is infested with trichinae does not differ in 

 appearance or in taste from uninfested pork. The trichinae that occur in 

 the flesh of hogs are very small, measuring only about one twent)'-fifth 

 of an inch in length and about one eight-hundredth of an inch in width. 

 The individual worms are spirally rolled and enclosed in capsules which 

 are somewhat less than one fiftieth of an inch in diameter and hence, micro- 

 scopic in size. The capsules do not stand out in contrast to the meat, except 

 in infestations of long standing. Considering the minute size of encapsuled 

 trichinae, it is impossible, of course, under meat inspection procedure, to 

 detect their presence in pork with the naked eye. Microscopic inspection 



