CHAPTER XV 



T.^NIASIS 



As to the effect of tapeworms upon their hosts, it may be said in gen- 

 eral that serious disturbances are most hkely to be manifest when the 

 worms are numerous, in which case the morbid effect is brought about 

 by the operation of several factors. There may be a reduction or com- 

 plete occlusion of the intestinal lumen with the usual inflammatory and 

 toxic disturbances or displacements following interruption in the move- 

 ment of the intestine's contents. While, as a general statement, in- 

 vasion of the bile duct by tapeworms may be said to be rare, the fringed 

 tapeworm of sheep {Thysanosorna actinioides) frequently enters this 

 organ and therefore constitutes a more serious tseniasis in these animals 

 than that from the Moniezia species. Armed tapeworms, by the irrita- 

 tion from their hooks, will, essentially, set up an inflammation of the 

 mucosa proportionate to their number. Further, where the worms are 

 numerous, their appropriation of nourishment contributes to the mal- 

 nutrition of a catarrhal enteritis. In heavj^ infestations the toxins 

 elaborated by the worms undoubtedly play a considerable part in the 

 general systemic effect. 



The cystic forms of certain tapeworms have an important bearing 

 upon the sanitary control of meat food products. In our own country 

 this is especially true of the cysticerci of the two tapeworms of man, — 

 Tcenia saginata and T. solium, the cysts of the former being harbored 

 in beef, those of the latter in pork. The presence of these cysts in the 

 muscles or other parts of the bod}^ constitutes the disease known as 

 measles, to which affection the terms ''measly beef" and "measly pork" 

 have reference. While observed most frequently in the animals men- 

 tioned, measles may appear in sheep {Cysticercus tenuicollis, C. ovis), 

 and man is occasionally auto-infected by larvae (Cysticercus cellulosce) 

 of Tcenia solium which he harbors. 



Cestodes of the Horse 



Three species of tapeworms occur in the Equidae. In all the cephalic 

 armature and neck are absent, and all have a genital pore on the same 

 side in each segment. Nothing is known of their larval forms. 



1. Anoplocephala perfoliata (Taenia perfoliata). Fig. 91. Tseniidse 

 (p. 170). — The head is large, rounded, and provided with well-developed 



