Cestodes

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  • Topic: Cestoda, Taenia solium, Taenia saginata
  • Pages : 16 (2132 words )
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  • Published : February 2, 2013
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General  Characteristics  
Flat,  ribbon-­‐ like   White  or   yellowish     Dorsoventrally   flattened  

Few  mm  to   several  meters  

Sexes  are  not   separate  

General  Characteristics  
Adults  are  found  in  the  intestinal  tract  of  man   Body  cavity  and  alimentary  cavity  are  absent  

Excretory  and  nervous  systems  are  present   Complete  reproductive  system  is  present  in  every   proglottid  

Regions  in  Adult  Worm  
Scolex    
Head     Suckers   Hooks    

Neck    

Strobila    
Body  trunk   Proglottids    

Types  of  Proglottids  
Immature    
Male  and  female  organs  are  not  differentiated  

Mature  
Male  and  female  organs  have  become   differentiated  (male  organs  appear  first)  

Gravid  or  ripe  
Uteri  are  filled  with  eggs  (other  organs  have   atrophied  or  disappeared)  

Differences    
Points  of   differences   Pseudophyllidean     Cyclophyllidean    

Scolex    

Strobila    

Spoon-­‐shaped  with   slit-­‐like  sucking   grooves  called   bothria,  no  hooklets   Anapolytic     Do  not  shed   segments  

Quadrate,  with  4   cup-­‐like  suckers   with  or  without   rostellum   Apolytic     Shed  segments  

Differences  
Points  of   differences   Gravid   proglottid  

Pseudophyllidean     Cyclophyllidean    

Pore    

All  reproductive   All  reproductive   organs  are  present   organs  degenerate   Uteri  coils  in  rosette   except  uteri   form   Uterine  pore   Genital  pore     Median  ventral   Lateral  margin  of   surface   proglottid  

Differences  
Points  of   differences   Ova    

Pseudophyllidean     Cyclophyllidean    

Oval  operculated   immature     Coracidium   procercoid   plerocercoid  or   sparganum  

Larval  stages  

Spherical  non-­‐ operculated   embryonated   Cysticercoid   cysticercus   hydatid    

Differences    
Points  of   differences   Intermediate   host  

Pseudophyllidean     Cyclophyllidean    

2     Crustaceans     Fresh  water  fish  

1   Lower  forms  of   mammal     Arthropod    

Diphyllobothrium  latum  
 

Fish   Tapeworm  

Broad   Tapeworm  

http://www.revistaaquatic.com/aquatic/html/art1401/fig11.gif 3-01-08

Diphyllobothrium  latum  
 

Yellowish  grey    
Strobila  -­‐  egg-­‐filled   uterus  

3  -­‐10  m  in  length     5  -­‐15  years   http://www.revistaaquatic.com/aquatic/html/art1401/fig11.gif 3-01-08

Diphyllobothrium  latum  
 

Scolex    
Spatulate  or  spoon  

Bothria    
No  rostellum  and  no  hooklets  

Diphyllobothrium  latum  
 

Proglottid    

Mature     reproductive   organs   Terminal     shrink  and   empty    

Diphyllobothrium  latum  

Rosette   form  uterus  

http://pathmicro.med.sc.edu/parasitology/dip1.jpg 3-01-08

Diphyllobothrium  latum  
Ova  
Oval   Unsegmented     Inconspicuous   operculum  at  one  end   and  a  small  knob  at   the  other  end   A  single  egg  gives  rise   to  a  single  larva   Not  infective  to  man  

 

http://workforce.cup.edu/Buckelew/images/Diphyllobothrium%20latum%20egg.jpg 3-01-08

Diphyllobothrium  latum  
Larva    
Passed  first  in  water  and  then  in  the  respective  intermediate   hosts   3  stage   First  stage  larva   Coracidium   Ciliated  oncosphere  that  develops  from  egg  in  water   Second  stage  larva   Procercoid   Spindle-­‐like  solid  body  with  cephalic  invagination   Found  inside  the  cyclops  (the  first  intermediate  host)   Third  stage  larva     Plerocercoid   Head  is  invaginated  in  the  neck   Found  in  the  fresh  water  fish,  the  second  intermediate  host    

Diphyllobothrium  latum  
Final  Host   Man,  dog,  cat   Small  intestine   1st  I.H.   Cyclops  or  Diaptomus   2nd  I.H.   Fresh  water  fish,  pike,  trout,  salmon,  perch   Mode  of  Infection   Ingestion  of  imperfectly  cooked  infected  fish  or  roe  containing  ...
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