CHAPTER V 



COMPARATIVE STUDY OF SOME 

 IMPORTANT CESTODES 



TECHNICAL SUGGESTIONS 



Mature and ripe proglottides of Ta>nia saginata of man are readily 

 obtainable. The former is so similar to that of Taenia pisiformis that 

 it is not necessary to devote time to its study, but the ripe proglottides 

 should be available for comparison with those of Taenia solium, which 

 can be purchased from dealers. Demonstration specimens of the 

 cysticerci, entire and in section in beef or pork, should also be 

 purchased. 



Scolices of these worms are rarely available, but the everted heads 

 from the cysticerci of the two species are more readily obtainable. 



Hymenolepis nana and Hymenolepis diminuta are commonly found 

 in both wild and laboratory rats and mice. Whole mounts should 

 be made for morphological study. The cysticercoids of H. nana may 

 be obtained by feeding the eggs in numbers in bread and milk to rats 

 and sectioning the intestine 24 to 48 hours later. H. diminuta 

 developmental stages may be obtained most readily by feeding eggs to 

 adult meal beetles, Tenebrio molitor. 



Dipylidium caninum, and closely related species are very common 

 in pet dogs and cats. Their characteristic egg packets in fecal 

 material should be preserved in 10 per cent formalin. Cysticercoids 

 develop in larval fleas and may be found in a small percentage of the 

 adult insects from infected dogs. 



Diphyllobothrium latum is endemic in some sections of this country; 

 but, in general, reliance must be placed on dealers. If living speci- 

 mens are available, the eggs should be cultured in water at summer 

 temperatures and the ciliated embryos will escape in 10 to 12 days. 



Multiceps serialis is a widely distributed parasite of dogs. The 

 cystic state of this parasite is often noted in the muscles of rabbits. 

 Sections of such cysts should be made to show the multiple invagi- 

 nated heads. Experimental feedings of dogs are readily carried out, 

 if there are facilities for keeping the animals under control. 



Echinococcus cysts are most readily obtained from slaughter houses 

 in our Southern states. Sections of the cyst wall and mounts of 

 fragments of the germinal layer showing larval scolices should be made 

 or purchased. Strangely enough, the minute adult worms have been 

 very rarely found in dogs in this country. They should be sought in 

 examination of these animals in the South, due regard being taken of 

 the danger to humans from careless handling of infective material. 



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