436 VETEEINARY HYGIENE 



the intermediate host which renders the prevention of this 

 and other parasitic diseases possible. 



The intermediate type of life between one tapeworm and 

 its next generation is a cysticercus. Thus Tcenia solium of 

 man has its larval form in the Cysticercus ccllulosa of the 

 pig, the pig being infected by the ingestion of the human 

 tapeworm excreted with the fseces. The Cysticercus bovis is 

 the larval form of T. mediocanellata of man. T. canmrus of 

 the dog has its larval form in the Coenurus cerehralis of the 

 sheep. T. serrata of the dog is the Cysticercus pisiformis 

 found in the peritoneal cavity of hares and rabbits. 

 T. marginata of dogs forms the C. tenuicoUis found in cattle. 

 T. serialis, also of the dog, has its cystic form in the horse, 

 hare, and rabbit. T. echinococcus of the dog has its larval 

 form in the Echinococcus veterinorum, particularly met 

 with in the liver and lungs of ruminants. 



There are tapeworms of which the intermediate host is 

 unknown, T. expansa of sheep and cattle, for example, a 

 parasite which is capable of causing considerable destruc- 

 tion among lambs. 



The prevention of tapeworm is based on a knowledge of 

 its life-history. The cystic disease in the pig and ox is 

 caused by their consuming human excreta, or food soiled 

 with it, from men affected with these two varieties of tape- 

 worm, and in no other way can they get it. Obviously the 

 lietter observance of sanitary precautions in the human 

 23opulation is the point to aim at, while the thorough cook- 

 ing of suspected beef and pork is the solution of the 

 problem so far as man is concerned. The recognition of 

 this disease in the ox and pig, the so-called ' measles,' will be 

 <iealt with under the Inspection of Meat. 



The dog harbours the largest number of varieties of tape- 

 worm, and is the means of infecting sheep with Caiiurtis 

 ■cerehralis, and cattle with Cysticercus tenuicoUis and Echino- 

 coccus veterinorum. 



As a means of preventing the infection of sheep with the 

 brain hydatid or ' gid,' all dogs employed with sheep should 

 be treated every spring with any of the ordinary tapeworm 

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