1. Class Cestoda

2. General characters
All tape worms consist of long, multi-segmented body.
Cuticle of the body is provided with pores through which the worm takes its nutrients (no digestive system)
They are hermaphroditic.
The adult worm is divided into 3 distinct parts: Head (scolex), neck and strobilla
Head or scolex : usually provided with muscular suckers and crown of hooks (rostellum) to attach to intestinal wall.

3. General characters
Strobilla: the long segmented body consists of segments which are of three types (i) the immature segments which follow the neck region (ii) the mature segments containing both sex organs and are responsible for reproduction (iii) the gravid segments filled with fertilized eggs.
Eggs :contain hexacanth embryo
The worms have intermediate host except Hymenolipis nana

4. Examples of class cestoda
1- Taenia sp:
Taenia saginata
Taenia solium
2- Hymenolepis sp:
Hymenolepis diminuta
Hymenolepis nana
3- Dipylidium caninum
4- Echinococcus granulosus

5. Taenia saginata
Taenia saginata mature segment: nearly square, bilobed ovary, scattered testis, uterus:median tube (magnifier)
Taenia saginata gravid segment longer than broad branched uterus filled with eggs (magnifier)
Egg of Taenia sp. circular,radiating double wall (H.P).

6. Taenia saginata Location of adult: small intestine of man
Intermediate host : cattle
Infective stage : cysticercus bovis
Mode of transmission: eating insufficiently cooked meat containing cysticercus bovis
Diagnosis: eggs & gravid segments in stool
Disease: Taeniasis

7. Taenia solium Cysticercus in section of muscle
Taenia solium scolex: rostellum with 2 rows of hooks (spines) and 4 suckers

8. Taenia solium Location of parasite:
Taeniasis: Adult worm in small intestine of man
Cysticercosis: Cysticercus (larval stage) in muscle or brain of man
Intermediate host :
Taeniasis: Pigs
Cysticercosis: man
Infective stage :
Taeniasis: cysticercus cellulosae
Cysticercosis: eggs
Mode of transmission:
Taeniasis: Eating undercooked pork containing cysticercus cellulosae
Cysticercosis: Autoinfection with eggs
Diagnosis:
Taeniasis: eggs & gravid segments in stool
Cysticercosis is diagnosed by X ray
Disease: Taeniasis, cysticercosis

9. Hymenolepis diminuta (rat tape worm)
Mature segments: broad than long characterized by 3 testis and one ovary in each segment (magnifier)
Gravid segments : broad than long, enlarged uterus containing eggs (magnifier)

10. Hymenolepis diminuta
Location of adult: small intestine of rat occasionally man
Intermediate host: rat flea
Infective stage: cysticercoid
Mode of transmission: ingestion of rat flea containing cysticercoid
Diagnosis: eggs and gravid segments in stool
Disease: hymenolepiasis

11. Hymenolepis nana
Mature segments: broad than long characterized by 3 testis and one ovary in each segment (L.P)
Gravid segments : broad than long, enlarged uterus containing eggs (L.P)

12. Hymenolepis nana Very small 25 mm
Location of adult: small intestine of man
Intermediate host: none
Infective stage :eggs
Mode of transmission: eating food contaminated with eggs or autoinfection
Diagnosis: eggs in stool

13. Dipylidium caninum (dog tape worm)
Mature segments: longer than broad,
2 genital pores, testis and ovaries
Gravid segments: Longer than broad, wall deformed, enlarged uterus filled with eggs

14. Dipylidium caninum
Egg packet
Scolex showing 4 suckers

15. Dipylidium caninum
Location of adult: small intestine of dogs, occasionally man
Intermediate host: dog flea
Infective stage: cysticercoid
Mode of transmission: ingestion of dog flea containing cysticercoid
Diagnosis: egg packet in stool
Disease: Dipylidium caninum infection

16. Echinococcus granulosus
Adult worm:
scolex, immature, mature and gravid segments (L.P)
Scolex from hydatid sand

17. Echinococcus granulosus
Location of adult: small intestine of dogs
Location of hydatid cyst : liver,lung, CNS and bone in man, cattle and sheep
Intermediate host: cattle, sheep (man is an end stage intermediate host)
Infective stage: eggs in feces
Mode of transmission:
man is infected by ingestion of eggs in dog feces
Diagnosis: identification of hydatid cyst by X ray
Disease: hydatid disease