3l6 READINGS IN BIOLOGICAL SCIENCE 



tically the entire population is infested; in certain parts of Syria, one third 

 of the population is infested. In countries where beef is commonly cooked 

 the extent of the infestation is more limited. 



Under federal meat inspection beef carcasses showing an excessive in- 

 festation with tapeworm cysts are not passed for human food, thus cutting 

 off the most fertile source of infection. During the past five years, the 

 total number of beef carcasses condemned on account of tapeworm in- 

 festation was somewhat under i,ooo out of a total of over 50 million cattle 

 slaughtered under federal inspection. During the same period, however, 

 over 135,000 beef carcasses were retained on account of infestation with 

 tapeworm cysts. Under federal meat inspection the retained carcasses which 

 contain only one dead and degenerated cyst are passed for food following 

 the removal of the cyst and adjacent parts, and a careful inspection to make 

 sure that no other cysts are present; carcasses showing a moderate infesta- 

 tion are not passed until after the removal of all visible cysts and subsequent 

 refrigeration of the carcasses for a period of not less than six days and at a 

 temperature definitely known to be fatal to the vitality of these parasites, 

 or such carcasses are cooked at a temperature that is known to be destruc- 

 tive to the vitality of these tapeworm larvae. Carcasses showing a heavy 

 infestation, or a pathological condition of the muscles indicative of such in- 

 festation, are condemned. 



It should be borne in mind, however, that only about two thirds of the 

 food animals slaughtered in the United States are subject to federal inspec- 

 tion or under imperfect inspection. Slaughtering done on the farm for 

 home consumption is not, of course, subject to any official inspection. 

 Actually, however, even the best kind of inspection can not guarantee per- 

 fect results so far as the detection of tapeworm cysts in beef is concerned, 

 because in most cases the degree of infestation is slight and a large propor- 

 tion of slightly infested carcasses necessarily escape even the most careful 

 inspection. The actual number of cases of infestation in cattle with larval 

 tapeworms is probably much greater than that shown by the figures cited. 

 From a practical viewpoint, however, it seems scarcely possible to effect a 

 more thorough inspection for tapeworm cysts than is done under existing 

 requirements. The inspection that is made eliminates most of the carcasses 

 that are likely to transmit tapeworm infestation to human beings; the car- 

 casses that are passed without detecting these parasites probably have only 

 slight or almost negligible infestations. 



As in the case of the fish tapeworm, the beef tapeworm in many cases 

 may produce no noticeable symptoms. This is particularly true of cases 

 involving robust individuals. Delicate and nervous persons and children 

 may show, at times, rather alarming symptoms, including severe gastro- 

 intestinal disturbances, nausea, and vomiting. Nervous persons may show 

 convulsions and even some severe reactions that are suggestive of epilepsy. 

 Sometimes tapeworm infestation gives rise to emaciation and anemia. On 



